SIE909_Masters_Project_Allen_Deliverable3_FINAL_Revised 25 April

Engineering Management Masters Project Deliverable #3

C–17 Globemaster

Max Gross Weight and Reduced Formation Spacing Study

of the

T–11 Personnel Parachute System

Keith AllenArmy Test and Evaluation Command

Yuma Test CenterU.S. Army Yuma Proving Ground

Yuma, Arizona

Produced for Dr. Ricardo ValerdiUniversity of Arizona

Department of Systems and Industrial Engineering

SIE 909 Systems Engineering Masters Final Project Deliverable No. 3

April 2015

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TABLE OF CONTENTS

SECTION 1. INTRODUCTION....................................................................................................1

1.1 System Description................................................................................................................1

1.2 Summary................................................................................................................................3

1.3 Test Program History.............................................................................................................3

1.4 Conclusions............................................................................................................................5

1.5 Recommendations..................................................................................................................5

SECTION 2. SUBTESTS...............................................................................................................7

2.1 C-17 Wake/Vortex Data Collection and Analysis.................................................................7

2.2 Fuel Delivery Gross Weight Estimation Tool.....................................................................22

2.3 System Safety And Risk Analysis.......................................................................................23

SECTION 3. APPENDICES......................................................................................................A-1

A. Test Criteria....................................................................................................................A-1

B. References......................................................................................................................B-1

C. Additional Data..............................................................................................................C–1

D. Abbreviations.................................................................................................................D–1

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ABSTRACT

Formation geometry between multiple C-17 aircraft is based on reducing the interaction of C-17 wake vortices (often called wing tip vortices) with parachutists. Reducing the formation geometry of a multi-ship C-17 airdrop formation involves examination of the interaction of parachutists and wing tip vortices that are created as a result of a C-17 aircraft in formation. The currently used formation geometry is based on a conservative estimate and safety margin that is not based on empirical measurements. The author develops a test design of flight and modeling experiments that measure actual wing tip vortices generated from a C-17 in standard personnel air drop profiles, then applies these measurements to an analytical and statistical model to better understand the user risk level in performing air drop missions in adjusted formations. Results from this effort can be used to recommend future live airdrop testing (mannequin and then live) to validate reduced formation geometries. The findings for this effort have a wide array of benefits for both the military aviation community, as well as the commercial aviation community. Wing tip vortices at airports around the world are a major cost driver of the timing of aircraft landings and takeoffs. Airport traffic control must ensure the disruptive vortices are dissipated fully before a commercial aircraft can utilize the runway, in turn driving time, fuel and other costs. Current modeling suggests that vortices of large cargo aircraft, such as the 747 and C-17 contain radial velocities upwards of 150-200 feet per second (ft./s), which could significantly affect time and cost of launching and recovering commercial aircraft as well as catastrophic effects on parachutists contacting the vortices.

Additionally, a technical risk analysis was performed for the T-11 parachutist in order to aid stakeholders in better understanding the risks of conducting a personnel mass exit operation. This includes risks associated with both increasing the gross aircraft weight of the C-17 aircraft only.

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SECTION 1. INTRODUCTION

1.1 SYSTEM DESCRIPTION

1.1.1 C–17 Globemaster III Aircraft

The C–17 Globemaster III aircraft is the United States Air Force’s (USAF) primary long range, heavy transport aircraft. It has a high wing lift and can deploy up to 102 paratroopers in a single pass from the troop doors. It can also carry over 170,000 pounds (lb) of palletized cargo and vehicles. The C-17 has a maximum speed of 450 knots and a maximum range of over 2,400 nautical miles and is powered by four Pratt and Whitney F117–PW–100 turbo fans. The C–17 is capable of landing and taking off on improved and unimproved runway surfaces. The C-17 replaced the C-141 in the mid-1990s for the deployment of the Global Response Force (GRF) mission. The GRF is the U.S. Army’s primary global, fast response airborne expeditionary airborne insertion force. Figure 1.1–1 shows the C–17 aircraft.

Figure 1.1–1. C–17 Globemaster III

1.1.2 T–11A Non-Maneuverable Static Line Personnel Parachute System

The T–11 is a multi-component personnel airdrop system consisting of three primary systems: the pack tray assembly, the main canopy, and the chest mounted T-11R reserve parachute. The harness has nine points of adjustments in order to accommodate both the 5th percentile female and 95th percentile male paratrooper. The T-11 main canopy is a cross-cruciform design and utilizes two of the most important characteristics of cross parachutes: inherent stability and a gentle opening. The T-11 differs from the conventional cross parachute with a significantly lower aspect ratio, shorter suspension lines, and improved materials. The

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http://upload.wikimedia.org/wikipedia/commons/5/50/C-17_2006-05-10_F-2559D-003.jpg

combination of aspect ratio, suspension line length, and canopy material porosity results in an optimized combination of drag area, stability, opening time, and opening shock. The T-11 deployment sequence is illustrated in figure 1.1–2.

Figure 1.1–2. T-11 Deployment Sequence

The T-11 replaced the T-10 in 2009 as the Army’s primary mass tactical personnel parachute system. The T-11 was shown to have significantly different flight performance characteristics than the T-10 during Developmental Testing (DT) conducted at the U.S. Army Yuma Test Center (YTC) in 2005 and 2006. Compared to the T-10, the T-11 was shown to have reduced opening shock, slower and more controlled deployment, slower decent rate, reduced leg injury rates and less oscillation under canopy.1.2 SUMMARY

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a. Test Authority. U.S. Army Test and Evaluation Command (ATEC) authorized this Developmental Test (DT) effort under the ATEC project No. 2013–DT–YPG–SOSPT–F3184. Funding was initially to be managed by Program Manager-Soldier Clothing and Individual Equipment (PM–SCIE) at Natick Soldier Research, Development and Engineering Center. However, this test program is not a PM–SCIE program since it is not testing a material solution. As a result, the project will be managed by ATEC (YTC test officer staff) and reported directly to Department of the Army G–3/5/7 staff. Additionally, due to the nature of the funding source and visibility, the program is on the oversight list for the Office of the Secretary of Defense (OSD) Director of Operational Test and Evaluation (DOT&E). The requirements for this program have been developed by the YTC test officer (the student for this project) and coordinated directly with DA, DOT&E and the U.S. Army user community through the Test Program Working Group (TPWG). The user community for this program consists of the 18th Airborne Corps and the 75th Ranger Regiment. The test objectives and requirements for this test are derived directly from the user defined operational requirement statement stated in appendix B, reference 3 and described in Section 1.4.

In 2013, the student author of this project was enrolled at the University of Arizona as a graduate student. The student is seeking a Masters of Science in Engineering Management. As a result of graduation requirements, the student coordinated with the Engineering Management department staff to utilize this project to fulfill requirements for the Systems and Industrial Engineering (SIE) 909 Master’s Project graduation requirement. This project is offered as the third of deliverable to fulfill a total of 6 credit hours of SIE 909 that spans the fall 2014 and spring 2015 semesters.

b. Test Objective. The overall goal of this study is to collect empirical flight data to support continued calibration, validation and accreditation of models for FSR and fuel estimation. The aim of this portion of the project was to show how a model(s) could be developed and utilized to assess the performance and risk of adjusting the formation geometry during a multi-echelon mass exit personnel airdrop with the T-11. The author demonstrated the test and evaluation strategy, model development and which variables that have the most significant effect on the system. The author performed a technical risk assessment on the IGW portion of testing. As a secondary effort, the author developed a separate model to better understand C-17 fuel consumption during personnel airdrops (shown in a separate report).

1.3 TEST PROGRAM HISTORY

When the C–17 replaced the C–141 as the USAF’s long-range, strategic, heavy airdrop aircraft in the mid-1990’s, several incidents of severe air disturbance were observed by the Operational Test (OT) team when conducting testing with the T–10. The air disturbances caused several parachutes to collapse or oscillate severely. Many paratroopers had to deploy their reserve parachutes because of their collapsed main canopies and the increased rate of descent (induced velocity). These disturbances were caused by the aerodynamic wake and vortices that large cargo aircraft create while in-flight, exacerbated by moderate to high engine power levels and extended flap settings at personnel airdrop speed (130 Knots Indicated Air Speed [KIAS]).

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Additional testing was then conducted with multiple C–17 aircraft to establish a formation element geometry that assured low risk of wake/vortex interactions with paratroopers while allowing the maximum number of soldiers to be delivered to the ground for an operational mission. A single element formation is defined as three aircraft flying in proximity, but at a distance that would minimize the inherent hazards created by wake/vortex effects. The lead aircraft is designated as Aircraft 1, the middle as Aircraft 2, and the final as Aircraft 3.

During this testing, 690 mannequin airdrops and 41 live jumps were conducted without an encounter from the second and third aircraft in the element formation. As a result of this testing, the USAF and U.S. Army testers agreed that although wake/vortex interactions cannot be completely avoided, minimum spacing between aircraft must be such that a paratrooper does not encounter the wake/vortex during its peak intensity within a single element. As a result, approved minimum spacing between aircraft in a single element was established and is shown in figure 1.3–1.

Figure 1.3–1. Current Minimum Spacing between C–17 Aircraft in a GRF Air Drop

These C–17 formation airdrops were conducted using the T–10C parachute system within the minimum allowable spacing. All distances are wing-tip to wing-tip for lateral spacing or tail to nose for longitudinal spacing. The spacing geometry was developed as a result of this testing and in a cooperative effort between various USAF and U.S. Army agencies, including wake/vortex experts at Wright Patterson Air Force Base. The minimum spacing shown in figure 1.4–1 is used when there is a headwind directly opposite to the direction of flight or in a no-wind condition. However, it is virtually impossible for trailing aircraft within the element to maintain an exact position relative to the lead aircraft. Therefore, as a result of the testing, a plus or minus (±) 500-foot (ft) longitudinal tolerance and a ± 200-ft lateral tolerance was established.

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Wingman Tolerances:± 500 ft. Longitudinal Spacing

± 200 ft. Lateral Spacing

*Spacing Dimensions not to scale

When the wind is offset to the right or left, the formation of aircraft will echelon to either the right or left in order to keep paratroopers away from the wake/vortex. In either case, the trailing aircraft will always fly upwind from the lead aircraft. Additionally, lateral spacing between aircraft becomes greater as the wind drift increases. Wind drift and spacing of the aircraft are described in section 2 of this test plan. Wake/vortex avoidance is assured by maintaining the proper approved lateral and longitudinal spacing between aircraft. Also, instituting no-airdrop procedures when aircraft are out of position ensures paratroopers are not exposed to unsafe conditions.

Furthermore, drop zone (DZ) width is an additional consideration as formation geometry increases. The formation must not be so wide that increases risk exists for paratroopers to land off the DZ. These considerations limit a single element to three aircraft. A minimum width and length for the DZ was developed and is described in section 2 of this test plan. The inter-echelon spacing (spacing between echelons) was not changed as a result of this testing due to very limited empirical data sets of wing tip vortex data. The concern of the test team was the understanding that atmospheric conditions have a high amount of influence on the behavior of the wing tip vortices, and that another detailed study was needed to address these risks. The current inter-echelon (lead aircraft to lead aircraft) spacing remains 32,000 ft., which equates to approximately 2.5 minutes of separation time between echelons.

1.4 CONCLUSIONS

1. Analysis from the IGW project indicates that performing mass exit personnel air drop missions from the C-17 at 400,000 lb. gross aircraft weight remains a medium residual risk.

2.The YTC test team has currently processed 24 individual flight profiles as shown above. The teams’ conclusions at the time of this writing include:

a. Cross Wind has a significant effect on the position of the vortex over its lifecycle. Wind speeds over 3 knots are causing movement of the vortex.

b. For the first 60 seconds of the vortex lifecycle, vortex pairs descend at a higher and constant rate.

c. The descent rate for the right vortex is typically higher than the left vortex. One hypothesis for this difference is certain flight profile variables such as crab and deck angle effecting the pitch and yaw of the aircraft. The YTC test team is currently conducting a separate study using correlation analysis to determine the possible causes of this.

1.5 RECOMMENDATIONS

The test team recommends a residual risk of MEDIUM be applied to all C-17 mass exit personnel missions at or below 400,000 lb. Risk above this gross weight value is unknown.

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The test team recommends continued testing to take wake/vortex measurements in a variety of terrain and atmospheric conditions, as these factors have great effect on the behavior of wake/vortices. To date, only desert day and night conditions have been tested at low altitude. The test team recommends repeating the vortex collection process in a variety of terrain and atmospheric conditions including:

a. Low and High DZ Altitudes

b. High and Low Humidity Conditions

c. Day and Night Conditions

d. Mild and Hot Temperatures

e. Flat and Mountainous Terrain

2. Based on test events conducted in April 2014, the test team recommends the following LIDAR and Twin Otter setup:

a. Use of Raster Scan rather than coordinate scan at 10 samples/second

b. Use ~20dB attenuation when possible

c. Flight Configuration 1 and 1 Revers produced most comprehensive data sets. Configuration 4 may not be as useful as previously thought for calibrating the Draper model because of the limited amount of vortex pair time collected. The aging of the vortex was not apparent with this configuration.

d. Use slower sweeps to improve lateral boundary determination.

e. The test team recommends more deep stability layer cases (night time or over cold water) to calibrate the model to an ideal baseline vortex behavior.

The author of this study recommends an in-depth verification, validation and accreditation of both the wake vortex and fuel estimation models. The objective of this study was to begin that process by collecting empirical data so that future models could be fielded to the user community for operational use. Continued calibration, verification, validation and accreditation should be conducted as soon as possible if the user community desires to get the most benefit out of these studies.

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SECTION 2. SUBTESTS

2.1 C–17 WAKE/VORTEX DATA COLLECTION AND ANALYSIS

2.1.1 Objective

Collect empirical wake vortex data during C–17 flights to support updating the Vortex Encounter Modeling Tool and model validation.

2.1.2 Criteria and Analysis

YTC Air Delivery test personnel collected and analyzed C–17 wake vortex data gathered during this test as presented in table 2.1–1.

Table 2.1–1. Criteria and Analysis for the FSR with MannequinsApp A,

Item No. Criteria Analysis

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Record empirical measurements of the wake/vortex pair that are generated by a single C–17 during standard training and tactical airdrop flight profiles, in a variety of atmospheric and terrain conditions

MET. Criterion is considered met when 143 total personnel airdrop profiles were successfully conducted, using LIDAR to record behavior of vortices and meteorological conditions.

2

Conduct statistical hypothesis testing of the Vortex Modeling Tool by incorporating empirical C–17 wake/vortex measurements in order to determine level of suitability in using the tool to aid in analysis of reduced formation geometry.

Partially MET. Criterion is partially met as data sets are still being reduced at the writing of this report. Project funding issues in 2014 and 2015 prevented further analysis to be completed.

3

Conduct comprehensive Vortex Modeling Tool model runs in varying GRF airdrop formations, atmospheric, and terrain conditions in order to analyze the risk of reducing formation spacing.

Not Tested. Current data reduction and modeling is still in process for this subtest.

LEGEND:App – appendixFSR – Formation Spacing ReductionGRF – Global Response Forcelb – pound

LIDAR – Light Detection and RangingNo. – numberYTC – Yuma Test Center

It is important to note that the information contained below for this subtest represents the most up to date analysis conducted for this project. A complete and comprehensive analysis for this subtest cannot be made at the time of this writing because of funding issues preventing a comprehensive study. The information contained herein is presented as an update to the current on-going effort and not as a final report.

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2.1.3 Test Procedures and Data Required

During discussions with the C–17 IGW/FSR Integrated Product Team (IPT) and during execution of the IGW, it was determined that an additional phase must be added to the current FSR test program documented in the original version of this YTC test plan. The basis of the discussion centered on the use of the Vortex Modeling Tool, developed by NSRDEC and Draper Labs, to analyze adjusted formation geometries before paratroopers and aircrews perform live airdrop missions using updated procedures. The Vortex Modeling Tool is a MatLab-based computer simulation that allows users to investigate the wake/vortex behavior of different formation geometries and this potential for adverse wake/vortex interactions. Figures 2.1–1 through 2.1–3 are example simulation runs from the model.

Figure 2.1–1. Input Flight Variables Screen Using Graphical User Interface

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Figure 2.1–2. Sample Modeling Runs Showing Jumpers Contact Wake/Vortices

Figure 2.1–3. Alternate View of Modeling Runs Showing Jumpers Contact Wake/Vortices

The Vortex Modeling Tool is based on numerical vortex model developed by Blake (app E ref 7) and described further in reference 8. The basic model includes simple two-degree-of-freedom jumper trajectories that interact with vortex pairs from a given set of user defined variables as published in both reference 8 and 9. The analysis is designed to be modular and can

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be updated to include other analysis and additional data, such as empirical vortex or paratrooper data. The main output of a model run is tabular and graphical results, which depict the number of paratroopers in a simulation run that contact the wake vortex such that their vertical velocity increases past a user-defined amount. The graphical displays can be used to show when and where the contacts are occurring during the airdrop.

The Vortex Modeling Tool represents the best simulation the test team currently has available to assess the risk and potential numbers of contacts during the adjustment of a formation airdrop. Although the trajectory data for the T–11 is well known and characterized in the model, there is less confidence in the characterization of the C–17 wake/vortices represented in the model. This is due in part to there being limited sets of empirical data on C–17 wake/vortices, as well as the information in the Vortex Modeling Tool being mostly based on Blake’s numerical data models.

As a result of this assessment, the test team collected empirical data on C–17 wake/vortex pairs during actual C–17 flights. The data sets from this analysis are provided in the Excel “C17_FSR_Event Matrix_April 2014_v3.xlsx” file.

At this time, the test team is unaware of any specification regarding the number and type of paratrooper to vortex interactions that would constitute a formation geometry that is unacceptable. However, according to the T–11 program Test and Evaluation Plan and Operational Requirements Document, the T–11 reserve landing descent rate should not exceed 27 feet per second (ft/s), which is assumed to be an acceptable descent velocity that can provide a combat ready paratrooper to the DZ. Therefore, for the purposes of this FSR assessment, a paratrooper’s landing velocity should not exceed 27 ft/s under the T–11 main parachute, as induced by the C–17 wake/vortex. In accordance with the draft FDSC for this project, the team’s default criteria for the modeling runs will be such that an induced vertical velocity above 27 ft/s at landing will be considered a wake/vortex interaction that is unacceptable. Additionally, any interaction with the wingtip vortex core that would collapse a parachute is unacceptable.

In order to capture C–17 wing tip vortices, the YTC test team used a Doppler Light Detection and Ranging (LIDAR) system that is operated by the Naval Postgraduate School (NPS) in Monterey, California (CA) in conjunction with Simpson Weather Associates. This Twin Otter Doppler LIDAR (TODWL) is an updated version of the Wind Tracer LIDAR system that is commonly used at airports to measure atmospheric disturbances due to aircraft take-offs and landings. The test team used the TODWL, an airborne 2um coherent Doppler Wind Lidar (DWL), to obtain line-of-sight observations of wind speed, aerosols, and turbulence. The aircraft is the Navy’s Twin Otter operated by the NPS in Monterey, CA. The DWL is owned by NPS and operated by Simpson Weather Associates, Incorporated. The TODWL has been flown on multiple missions since 2001. Figure 2.1–4 shows the Twin Otter in its most recent configuration.

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Figure 2.1–4. Airborne LIDAR System, TODWL

Unlike a ground based system, an airborne LIDAR system gave the test team more flexibility in mission planning and allows more accurate capture of the wake vortices as they dissipate in time across an area. Figures 2.1–5 and 2.1–6 show examples of historical data measurements and sampling rates.

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Figure 2.1–5. Example Wind Sounding

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Investigating the impacts of LLJs and OLEs on ABL exchangesand transports using an airborne Doppler wind lidar

G.D. Emmitt1, R.C. Foster2, K. Godwin3 and S. Greco1

1 – Simpson Weather Associates, Charlottesville, VA, USA; 2 – APL, Univ. of Washington, Seattle, WA, USA; 3 – KSG Science, Starkville, MS, USA

CIRPAS Twin Otter with CTV below

Twin OtterProbe Data

TODWL Time/height Cross sections

Towed VehicleFlux Data

Objectives

● Utilize the Twin Otter Doppler Wind Lidar (TODWL) and Controlled Towed Vehicle (CTV) to take ABL wind and flux measurements over marine and coastal environments

● Extend prior investigations (2001-2008)of LLJs and OLEs in the MBL and PBLs.

● Investigate and characterize the presence of rolls (OLEs) at the boundaries of stratocumulus topped MBLs.

● Study the potential impact on the development and implementation of the EDMF into forecast models.

TODWL Data Description

Structure Prospecting with TODWL

● Feature prospecting uses a very shallow angle below the horizon (~ -1 -3 degrees for a 300m flight altitude).

● Results in ~ 2 m vertical resolution and 50 m horizontal resolution with ~10 meter sliding sample.

● It takes ~ 40 seconds to profile 100 meters below the aircraft.

9/30/2012 Case Study● Processed lidar data in search of organized

aerosol/wind structures below the Twin Otter ● Processed Twin Otter instrument and CTV data for

time series of u, v, w, q, and ϴ.● Match up times and their features from the TODWL

and CABIN data sets near flight level and CTV at CTV cruise levels.

9/30/2012 Flight Path

TODWL LOS, SNR and Spectral Width

TODWL Rad. Velocity, SNR and Spec. Width( Two Color Processing)

Summary of Segment Statistics

Summary

● The combination of an airborne Doppler Wind Lidar and a Controlled Towed Platform holds promise of a transformation of how we investigate air/sea exchanges and construct flux parameterizations for use in numerical weather models.

● This research is being funded by Dr. Ferek of the Office of Naval Research.Speed Direction Theta

Attribute Performance Metric

Comments

LOS resolution (applies to vertical profiles of 3D winds as well)

50 m Range resolution to hard targets (ground or dense cloud) can be better than 10 meters.

U,V,W resolution < 10 cm/s < 5cm/s for stationary ground based operations

Maximum range 6 -30 km Very dependent upon aerosols

Time to complete full step stare conical scan for wind profiles

~ 20 sec 12 point step stare with .5 -2 second dwells

Sampling frequency 100 Hz Integration of several shots is typical to improve range performance

TODWLscanner

STV

Particleprobes

SurfaceTemperatureSensor

Twin Otter Aircraft

Figure 2.1–6. Atmospheric Disturbance Measurements

The TODWL can be used in several scanning modes. For vertical profiles of the three-dimensional (3D) wind field, the scanner is programmed to perform 20- or 30-degree half angle conical scans above or below the aircraft. When the aircraft is on the ground, upward conical scans are normal. When the aircraft is flying, both up and downward scans are used. A conical scan takes 12 to 20 seconds to complete a 360-degree 12-point step stare. Sector scans of 90 degrees can be completed in 5 seconds.

When monitoring features that are primarily two dimensional, TODWL scans use either raster or fixed angle stares. Organized large eddies, mountain waves, ocean waves, or wake/vortices are best sampled using a simple Planned Position Indicator or Radar Height Indicator. From the aircraft perspective, this might be a lateral scan from nadir while navigating along the features major axis.

Two major limitations of the TODWL are its offset to data collection (400 m) and its inability to measure low wind speeds within the lowest 150 m of the atmosphere when looking down towards the ground. This ground interference is not critical for wind speeds greater than 2 m/s. The 400-m offset from the scanner is only a factor when looking straight up, which is not

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the desired test set-up for this project. In order to compensate for this limitation, the YTC test team recorded atmospheric readings at the test location using RAWIN discussed in IGW project, as well as adjusted the flight profiles throughout the flights as needed based on quick-look data.

In addition to obtaining vertical profiles of the horizontal wind at selected locations within the test area, the test utilized several flight profile options for the use of the TODWL to provide a 3D time series of C–17 wing tip vortices. The test team retained flexibility in adjusting these profiles based with input from USAF, LIDAR experts and Twin Otter aircrews. The overall regime for this testing is shown below:

a. C–17 passes over the DZ at altitudes between 525 and 1,250 ft AGL at 130 to 135 KIAS.

b. Current time between airdrop profile runs is 6 to 8 minutes.

c. Simulated drops were spaced 6 to 8 minutes to allow vortices to dissipate.

d. The centers of the twin vortices were generated ~170 ft apart.

e. The significant effects of those vortices can vary greatly in time (persistence) and space (drift modes).

f. The volume of regard for this study has dimensions that are still being studied. However, typical DZs for personnel have lengths of 12,000 ft and widths of 5,000 ft.

The ultimate goal of the flights during this phase of test was to get a wide distribution of wind speeds and directions with respect to the C-17 during the drop profiles as possible. Figures 2.1-7 and 2.1-8 show the distribution of wind speeds and directions.

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FIGURE 2.1-7. Wind Direction and Speed WRT to C-17 at Profile Altitude

FIGURE 2.1-8. Ground Wind Direction and Speed WRT to C-17

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These figures show that the YTC test team was generally successful in obtaining a wide distribution of wind speeds and directions with respect to the C-17 over the 143 flights, from both the altitude winds and the ground. It should be noted that all flight profiles flown by the C–17 were dry passes and NOT actual airdrops. The YTC test team simulated actual airdrop conditions by conducting the above C–17 profiles with the troop doors open and the wind deflectors deployed. Flight profiles were flown in both day time and nighttime conditions as shown in the C-17 Event Matrix summary

While the C–17 is flying the above flight profiles, the TODWL was flying one of the following flight profiles while recording wake/vortex data:

a. Configuration 1: C–17 Following Mode

In this case, the Twin Otter flies at an altitude of 5,000-7,000 ft AGL and above the C–17 while performing ±30 degree side-to-side sampling obtaining approximately 200 shots per side-side scan in 1 second. The width of the ground intercepts would be approximately 5,000 ft -7,000 ft. and thus the sample pattern was varied to accommodate modest cross track wind drifts of the vortices. If test team observed that more lateral drift is occurring (for example due to cross winds), the flight path of the Twin Otter was adjusted to keep the vortices within the TODWLs sampling domain.

Assuming a differential airspeed of 20 knots (e.g.) between the Twin Otter and the C–17, a complete 3D mapping of the vortices from the points of generation (wind tips) to a region of dissipation (defined by test group) could be obtained. The horizontal mapping could cover 2,000 ft per minute while drifting back over the vortices. The differential airspeed of the C–17 and Twin Otter could be changed to map larger/smaller areas of the vortices per minute.

In addition to wind profiles, vertical profiles of temperature (T) and humidity (RH) was obtained during ascents and descents of the Twin Otter. The TODWL system has its own GPS/Inertial Navigation System as does the Twin Otter, which allows rather precise navigation of the T, RH, and DWL data. A variation of Configuration 1 was utilized during testing that including flying a “revers” or head on profile with respect to the C-17. This allowed for capturing of wake vortices over a longer duration of time as they decay after generation

b. Configuration 4: Test Area Survey Flight

In this option, the TODWL system would remain over the test area (with lateral margins) to map the vortices as they dissipate within the interest area. The mobility of the Twin Otter allows the features to be tracked relative to their center of mass until they get well beyond the DZ.

Other configurations discussed in the test plan for this project were not used based on the input of LIDAR experts. It was deemed by the test team that these flight profiles would only produce limited amounts of test data. In addition to the TODWL, the following YPG-based instrumentation will be used:

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a. Still photography as described in the IGW project report..

b. IVTS as described in the IGW project.

c. An additional IVTS system was utilized in both aircraft to monitor the position and velocity of each aircraft over a moving map display. This system was operated by the YTC test team (author of this study) in order to ensure that both aircrews had awareness of where the other aircraft is at all times and to provide better command and control of all test events.

d. 1553 data bus recorder installed on the C-17 as described in the IGW project report.

e. RAWIN as described in the IGW project report.

The raw LIDAR data was collected and reduced into tabular and graphical form as shown in Figures 2.1-9 and 2.1-10.

FIGURE 2.1-9. Example of Vortex Downwash (Bright Red and Orange Color)

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FIGURE 2.1-10. Example Tabular Parameters Used for Vortex Model Update

It was decided by the test team to use the above parameters, as they are the most useful parameters already included in the original Draper model.

From this reduced data, the test team then can make several plots (as shown in Figures 2.1-11 through 2.1-13) and conduct observation of the behavior of the vortex during each individual flight, including vortex position versus vortex age. This is one of dozens of plots that are made for each individual flight.

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FIGURE 2.1-11. Example Height Versus Vortex Age

Finally, the tabular data from these plots can be placed in the Draper Vortex Model to show the following outputs:

FIGURE 2.1-12. Output of Draper Model With FSR Data Set Collected April 2014

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FIGURE 2.1-13. Output of Draper Model With FSR Data Set Collected April 2014

Additional data is provided in Appendix C. The YTC test team has currently processed 24 individual flight profiles as shown above. The teams’ conclusions at the time of this writing include:

1. Cross Wind has a significant effect on the position of the vortex over its lifecycle. Wind speeds over 3 knots are causing movement of the vortex.

2. For the first 60 seconds of the vortex lifecycle, vortex pairs descend at a higher and constant rate.

3. The descent rate for the right vortex is typically higher than the left vortex. One hypothesis for this difference is certain flight profile variables such as crab and deck angle effecting the pitch and yaw of the aircraft. The YTC test team is currently conducting a separate study using correlation analysis to determine the possible causes of this.

Work continues on the processing of the remaining data sets. Final conclusions and modeling results will be included in a final publishable paper at the conclusion of this study, which is projected to be end of 2015. The study will also conduct a statistical comparison of the original Draper model based on theoretical values with the updated model based on empirical data collected for this study.

As a result of the work conducted thus far, the YTC test team has made the following observations and lessons learned to be applied to future events:

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1. The test team continued collection of wake/vortex measurements in a variety of terrain and atmospheric conditions, as these factors have great effect on the behavior of wake/vortices. To date, only desert day and night conditions have been tested at low altitude. The test team recommends repeating the vortex collection process in a variety of terrain and atmospheric conditions including:

f. Low and High DZ Altitudes

g. High and Low Humidity Conditions

h. Day and Night Conditions

i. Mild and Hot Temperatures

j. Flat and Mountainous Terrain

2. Assuming funding is available to continue testing in a variety of other operational environments, the test team recommends the following LIDAR and Twin Otter setup:

a. Use of Raster Scan rather than coordinate scan at 10 samples/second

b. Use ~20dB attenuation when possible

c. Flight Configuration 1 and 1 Revers produced most comprehensive data sets. Configuration 4 may not be as useful as previously thought for calibrating the Draper model because of the limited amount of vortex pair time collected. The aging of the vortex was not apparent with this configuration.

d. Use slower sweeps to improve lateral boundary determination.

e. The test team recommends more deep stability layer cases (night time or over cold water) to calibrate the model to an ideal baseline vortex behavior.

21

2.2 FUEL DELIVERY GROSS WEIGHT ESTIMATION TOOL

2.2.1 Objective

Develop and then validate a fuel consumption and cost estimation model to more accurately forecast fuel requirements when planning personnel mass exit airdrop missions for the C-17 aircraft.


The student has successfully expanded the original fuel estimation model created for the SIE 564 Cost Estimation Class (FUDGE 1.0). The study assesses using cost driving factors such as airspeed, gross aircraft weight and distance flown to build an accurate forecast for fuel consumption and cost as presented in table 2.4–1.

Table 2.2–1. Criteria and Analysis for the Fuel Estimation ModelApp A,


4

Determine which factors significantly affect fuel requirements and gross aircraft weight

MET. Criterion is considered met because correlation and regression analysis led to an updated flight data sets from the IGW and FSR portions of testing.

5

Design a set of equations in a parametric model based on analogous historical flight models, as well as empirical flight data collected within the last year.

MET. Criterion was considered met when new equations from new training and validation data sets were successfully developed into a parametric model for fuel consumption. Validation of the model using statistical hypothesis testing was completed on the updated version of the model.

6

Provide an updated working example of the model in a typical mass exit airdrop environment

MET. Updated model provided in file named “FUDGE_Tool_Versions 1 and 2.xlsx”

LEGEND:App – appendixlb – pound

No. – number

2.2.3 Test Procedures and Data Required

Due to the length of the study, FUDGE 2.0 is presented in a separate document with the file name “FUDGE 2.0_Allen_SIE909_FINAL.pdf”. A Microsoft Word version of this document is also available, along with the tabular and graphical data used for the study in an Excel file named “FUDGE_2.0_Data”.

22

2.3 SYSTEM SAFETY AND RISK ANALYSIS

2.3.1 Objective

Complete the hazard analysis based on the test results for the C–17 IGW and FSR testing and develop risk severity matrix for residual risks found during testing.


YTC Air Delivery test personnel analyzed the T–11 parachute and C–17 interaction data gathered during this test as presented in table 2.3–1.

Table 2.3–1. Criteria and Analysis for the C–17 IGW System SafetyApp A,


7

Residual risk for deploying T-11 jumpers at increased gross weights up to 400,000 lb. shall not be more than current residual risk at 385,000 lb. (Medium).

Partially MET. Criterion for this subtest was considered met for up to 100 parachutists from a single C–17 when risks for the C–17 IGW/FSR test program were assessed for the entire test effort, using AR 385–10 as a guide. No additional risks for up to 100 parachutists or aircrew were found when conducting mass exit operations at 400,000 lb. gross aircraft weight. Modified procedures for parachutists and aircrew are not required. FSR testing has not been completed and will be included in future documentation. Residual risk for deploying parachutists from the C-17 at 400,000 lb. is medium.

LEGEND:App – appendix.AR – Army RegulationFSR – Formation Spacing Reduction

IGW – Increased Gross Weightlb. – poundNo. – number

The student author of this paper was not able to complete the risk assessment for the FSR portion of testing, as the test project has not been completed fully to date. Once the full test plan for FSR has been executed, future documentation will be published to include the risk to parachutists as a result of adjusting the formation spacing.

2.3.3 Test Procedures and Findings

The YTC test team reviewed all the data and test results to determine if there were any failures or anomalies experienced throughout the course of testing. No further analysis is required because no failures, anomalies, or unexpected results were seen. The YTC test team has determined that no additional risks beyond normal mass exit operations exist for a C–17 at 400,000 lb. There were several risks that have been identified with deploying T-11 parachutists from the C-17. Table 2.3-2 shows those risks, how each risk was mitigated and the remaining residual risk.

23

TABLE 2.3-2. C-17 IGW T-11 PARACHUTE HAZARD ANALYSIS TRACKING LIST (Ref. ATEC REGULATION 385-1)(1) (2) (6) (8) (10) (11) (12) (13) (14) (15) (17)

No. System / Subsystem / Unit

System Event(s) Phase Hazard Description Effect on

Personnel / SystemRAC

Before1 Recommended Corrective ActionEffect of

Recommended Corrective Action

Remarks StatusRAC After2

1. T-11 Harness,Shoulder adjustment / Main lift web adjustment

Operation, Donning

Incorrect sizing Discomfort and incorrect positioning of the riser release units and the reserve parachute ripcord.

IV A Med

Detailed donning and doffing procedure is described in the document:“PACKING INSTRUCTIONS 990080-20”

Hazard Reduced The training package addresses donning and doffing procedures.

Closed IV C Low

2. T-11 Harness, Chest strap

Operation, Donning

Incorrect chest strap routing

Potential for the jumper to fall out of the harness

I D High

The location of the reserve parachute attachment prevents the jumper from falling out of the harness in the case of a chest strap failure.The correct chest strap fitting procedure is detailed in the document:“PACKING INSTRUCTIONS 990080-20”

Hazard Reduced The potential of falling out of the harness is only present in the case of operational low altitude combat jump when the reserve parachute would not be worn.

Closed III E Low

3. T-11 Harness,Harness

Operation,Deployment sequence / during opening shock.

Harness structural failure

The parachutist can fall out of the harness.Equipment can be lost.

II C High

The harness is design in accordance with the current TSO standards, and all components were chosen to ensure adequate safety factor.The harness has been tested during Base Effort, Design Validation and Technical Feasibility Testing at maximum operating weight / speed. No degradation was observed.Tests were conducted in both Main only and Reserve only configuration.

Hazard Reduced Additional snatch and durability tests were conducted during DT and shown to meet specification.

Closed II E Low

1 Mishap Severity Category & Probability of Occurrence Level, and overall Safety Risk Assessment based upon governing System Safety Program. For example, I, A, (1), Extremely High. U. S. Army Test & Evaluation Command organizations use the Test Risk Assessment Matrix contained in ATECR 385-1, .2 Same as item (11).

24

TABLE 2.3-2. C-17 IGW T-11 PARACHUTE HAZARD ANALYSIS TRACKING LIST (Ref. ATEC REGULATION 385-1)4. T-11 Harness,

Main parachute riser release

Operation,Deployment sequence, opening shock

Riser release failure

- Separation of one or both risers from the harness.- Inability to release the riser while on the ground.

II C High

3-ring design replaced with proven Capewell Release during Developmental Testing. Capewell Release reliability and confidence level of .9999@90%.

Hazard Reduced Closed II E Low

5. T-11 Harness,Main parachute riser release

Maintenance / Packing,Main riser connection

Incorrect closing loop routing

- Premature release of one or both risers on opening shock.- Major damage to the release unit and inability to operate the release on the ground.

II D Med


Hazard Reduced Detailed riser release maintenance and assembly is described in the document:“PACKING INSTRUCTIONS 990080-20” page 1-5.

Closed II E Low

6. T-11 Harness,Main parachute riser release

Maintenance / Packing’Main riser connection

Incorrect lug positioning resulting in non positive lock of the mechanism

- Release of the riser on opening shock.- Total malfunction of the main parachute.

II C High

The design ensures that the cover plate cannot be closed if the lug is not fully inserted in the securing jaws.

Hazard Reduced Jump Master check prior to exit will ensure that the cover plate is in the closed position.Detailed instructions are provided in the document:“PACKING INSTRUCTIONS 990080-20”

Closed II E Low

7. T-11 Harness’Main parachute riser release

Operation,Deployment sequence, opening shock

Retaining loop failure

- Riser separation on opening shock- Total malfunction of the main parachute.

II D Med



25

TABLE 2.3-2. C-17 IGW T-11 PARACHUTE HAZARD ANALYSIS TRACKING LIST (Ref. ATEC REGULATION 385-1)8. T-11 Harness,

Main parachute riser release

Operation,Deployment sequence and descent

Inadvertent release cover opening during descent

Open access to operating levers, but open cover will not result in any injury or hazard to the jumper.

III C Med


Hazard Reduced Closed III D Low

9. T-11 Main parachute, Static line

Operation,Deployment sequence

Static line failure - No opening of the main parachute- The free falling jumper has to operate his reserve parachute

II C High

The static line used is the current approved Universal static line.Moreover, improved protection of the static line is provided by static line loops protection flaps, in conjunction with stronger and higher located retaining band stowage.

Hazard Reduced Detailed static line stowage procedure is described in the document:“PACKING INSTRUCTIONS 990080-20”

Closed II E Low

10. T-11 Main parachute, Main pack

Operation,Inside the aircraft, deployment sequence

Premature pack opening caused:- By movement of the jumper in the aircraft seat- As a result of poor exit.

- Jumper entanglement with static line and deploying main parachute- Out of sequence deployment- Main parachute malfunction

III C Med

A cover flap ensures curved pin protection and security.The pack profile is designed to accommodate the shape of the aircraft seat and encase the bottom of the deployment bag for greater retention.

Hazard Reduced The protection flap is easily accessible to allow other jumpers and the Jumpmaster to check the curved pin.

Closed III D Low

11. T-11 Main parachute, Deployment bag


Deployment bag lock

Towed jumper behind the aircraft

II D Med

The system uses a standard reliable deployment bag.Moreover, the suspension line stowage on the outside of the bag has been improved to further reduce the risk line entanglement.

Hazard Reduced Closed III E Low

26

TABLE 2.3-2. C-17 IGW T-11 PARACHUTE HAZARD ANALYSIS TRACKING LIST (Ref. ATEC REGULATION 385-1)12. T-11 Main

parachute, Deployment system


Drogue failure Delayed deployment of the main parachute

IV D Low

The drogue design is a flat circular parachute with its suspension tapes enclosed in a high porosity netting to prevent snagging and structural failure.The length of the connecting bridle between the drogue and the sleeve has been minimized to prevent potential snagging hazards.Tests have been conducted to demonstrate that the sleeve is still removed with a drogue in tow.

Hazard Reduced Closed IV E Low

13. T-11 Main parachute, Deployment system


Connection bridle structural failure

Sleeve separation from the main parachute at the end of the elongation phase

IV D Low

The ultimate strength of the connection bridle (1850 Lb.) is more than five times greater than the drag of the extractor drogue (~350 Lb.). Therefore a bridle failure is improbable.The tests carried out with the bridle disconnected from the main canopy did not indicate any deviation from the nominal deployment sequence.

Hazard Reduced Closed IV E Low



Connection bridle entanglement

- Partial retraction of the sleeve- Delay in the opening sequence- Potential damage to the crown of the canopy

III C Med

A specific stowage flap is designed to ensure sequenced deployment of the bridle and prevent bridle / canopy interaction.

Hazard Reduced Detailed instructions are provided in the document:“PACKING INSTRUCTIONS 990080-20”

Closed III D Low



Slider hang-up Partial main parachute inflation

III C Med

Potential for slider hang up was addressed during the stress analysis.The larks head knots positively prevent the grommets from jamming onto the skirt.Only one suspension line is routed per each grommet eliminating any chance of slider hang-up during opening. The suspension lines are also always under tension during packing and deployment.

Hazard Reduced Correct slider rigging and packing procedure is provided in the document:“PACKING INSTRUCTIONS 990080-20”

Closed III E Low

27


parachuteOperation,Deployment sequence

Crown damage Delayed or partial canopy inflation,

which could necessitate

reserve parachute activation

II C High

The stress analysis has demonstrated that the canopy largely meets the 2:1 required safety factor.Additional reinforcement patches were added to the highly stressed area of the crown.Tests have also demonstrated that the canopy can fully inflate after the removal of one complete panel.


17. T-11 Main parachute


Structural failure (Hem band, tapes…)

Canopy partial or total destruction, which could necessitate reserve activation.

II C High

The stress analysis demonstrated that the main seams / cross seams / hem reinforcing tape meet the 2:1 safety factor requirement.No structural failure was observed during any of the test drops (Base Effort, BV, TFT, DTIII).




Parachute entanglement during simultaneous door exit

Possible mid-air collision and entanglement of two parachutists.

I D High

The deployment system incorporating the sleeve design allows the canopy to inflate away from the immediate aircraft wake and reduces the potential of entanglement.The length of the connecting bridle between the drogue and the sleeve has been minimized to prevent potential snagging hazards.No deployment system contact, canopy collision or entanglement was observed during the single door multi jumper tests conducted from the C17 aircraft.

Hazard Reduced Results of IGW Testing conclude that entanglement/contact during deployment has same risk level as conducted during current operations.

Closed I E Med

19. T-11 Reserve parachute

Operation, Reserve parachute activation

Ripcord lock Excessive pull poundage to activate the reserveImpossibility to activate the reserve

II D Med

The handle design incorporates two specifically profiled tuck tabs to provide consistent pull force.Two curved pins reduce friction.A tight tolerance of the closure loop length ensures pull force consistency.

Hazard Reduced Reserve container closing procedure is provided in the document:“PACKING INSTRUCTIONS 990080-21”

Closed II E Low

28

TABLE 2.3-2. C-17 IGW T-11 PARACHUTE HAZARD ANALYSIS TRACKING LIST (Ref. ATEC REGULATION 385-1)20. T-11 Reserve

parachuteOperation, Prior to exit, on exit or during descent under main parachute

Inadvertent reserve container opening

- Possible jumper extraction from the aircraft- Possible entanglement of main and reserve parachute

II D Med

The center pull flexible handle reduces the risk of the handle being dislodged from its stowage on the aircraft doorframe.The handle can be covered by either hand during onboard movement near the aircraft door.The tuck tabs secure the handle and provide consistent protection of the curved pins.

Hazard Reduced No elastic is used to retain the handle and therefore they would be no degrading of the security of the handle stowage.

Closed II E Low


Operation,Reserve parachute activation

Reserve container lock

Inability to deploy the reserve in an emergency situation.

II D Med

The reserve closure loop design minimizes the number of flaps and associated grommets.The kicker spring pushes the flaps clear of the deploying canopy.The design allows the closing loop to position the kicker spring at the most efficient location to push the flaps and launch the canopy.



Operation,Reserve parachute deployment sequence

Reserve extractor malfunction

Inflation delay during low speed malfunction

II D Med

The reserve extractor is of lightweight with rapid inflation characteristics. It is launched in the relative airflow with the kicker spring.The scoops located in the apex area of the canopy provide assistance in the case of reserve extraction failure.

Hazard Reduced Canopy folding procedure to ensure maximum extractor efficiency is provided in the document:“PACKING INSTRUCTIONS 990080-21”

Closed IV D Low



Reserve entanglement with main parachute

High rate of descent and instability

I EMed

The reserve parachute and associated features (large diameter spring free extractor…) are specifically designed to offer maximum resistance to potential entanglement.No main and reserve entanglement was observed on all the drops conducted during Base Effort through DTIII.

Hazard Reduced Reserve activations with 10%, 30% and 100% main canopy conditions were shown to meet the specifications during Developmental Testing.

Closed III E Low

29

TABLE 2.3-2. C-17 IGW T-11 PARACHUTE HAZARD ANALYSIS TRACKING LIST (Ref. ATEC REGULATION 385-1)24. T-11 Reserve

parachuteOperation,Reserve parachute deployment sequence

Inadvertent reserve riser released

Total reserve malfunction

II D Med

The reserve parachute attachment is located at the shoulder point. Therefore, the jumpmaster can easily check that both hooks are properly attached.Because of their higher location, the hooks do not interfere with any other equipment.




Hardware failure Total reserve parachute malfunction

II D Med

The safety analysis has demonstrated that the hardware meets the 1.67 safety factor.No hardware failure or permanent distortion was observed after the high speed/ high weight tests conducted during Base Effort, DV, TFT and DTIII.




Structural failure (Hem band, tapes…)

Canopy partial or total destruction.

II D Med

The stress analysis demonstrated that the main seams / cross seams / hem reinforcing tape meet the 2:1 safety factor requirement.




Improper Deployment due to manufacturing defects


II B High

Conduct rigger awareness and training to test personnel.Perform Total Rigger Inspection (TRI) and in servicing of all test hardware.Ensure packing inspector is qualified.

Hazard Reduced System shown to have .9999 Reliability at 90% confidence during DT/OT testing and operational use.

Closed II D Med



System Malfunction due to packing errors


I D High Conduct Pack and Rigger Inspection Training to all packing personnel.


Closed I E Med


Operation, live jump from Aircraft to ground

Improper jumper actions

Personnel Injury I D High

Conduct basic airborne refresher training covering actions in the aircraft, proper exit procedures, and landing procedures.


Closed I E Med



Deployment malfunction due to improper equipment installation


I D High

Conduct Pack and Rigger Inspection Training to all packing personnel.


Closed I E Med

30



Deployment malfunction due to foreign objects in the pack


I D High

Perform 100% equipment inventory prior to and after each packing operation at each packing station..


Closed II D Med



No main parachute opening.


Conduct live jump operations at a minimum drop altitude of 1,200 feet AGL..


Closed I E Med


C-17 Dual Door Operation,Deployment sequence.

Jumper interaction due to center lining.

Personnel Injury, canopy partial or total destruction.

I D High

Conduct IGW in accordance with approved test plan.

Hazard Reduced The C-17 IGW Monte Carlo testing and analysis was conducted. It was determined that there is no greater risk then what the T-10 system is experiencing.

Closed II D High



Parachute Equipment Failure.


I D High

Perform Total Rigger Inspection and In-Servicing of all Test Hardware.


Closed I E Med



Jumper inability to activate the reserve parachute


Conduct pull force testing during the in processing of equipment.Conduct ATPS specific airborne refresher training


Closed I E Med



Reserve Entanglement with the Main Canopy


I D High

Conduct ATPS specific airborne refresher training.


Closed I E Med



Slow Opening Main Parachute


I D High

Conduct live jump operations at a minimum drop altitude of 1,200 feet AGL.Conduct ATPS specific airborne refresher training.


Closed I E Med

31


parachuteOperation,Flight between deployment sequence and landing on DZ.

Mid-air collisions and entanglements


I C High

Conduct Entanglement Test with follow-up evaluation during DT/OT.Conduct ATPS specific airborne refresher training.Subject matter expert review of video data is required after every event with concurrence to continue with testing.


Corner Vent Entanglement Testing shows no additional risk to parachutists during collisions and entanglements.

Closed III C Med



Main Canopy does not deflate upon ground impact.

Personnel Injury, damage to canopy

III C Med

Provide specific Jumper CRU Training activation procedures.Implement a starting minimum jumper rigged weight of 200 pounds. Reduce the minimum jumps weight by 10 lb. increments when the higher weight has been cleared by previous jump where the ground wind speed was in excess of 8 kts.


Closed III D Low



Obstacle Collision on the DZ


II D Med

Minimize equipment and personnel on the DZ during operations.Validate maneuvering capability of the ATPS main parachute prior to jumps on drop zones with significant obstacles.


Closed II E Low



Premature pack opening onboard the aircraft


I D High

Perform onboard pack closing pin and static line inspection immediately after jumper standup on the aircraft.


Closed I E Med

32



Inexperienced jumpers


I D High

ATEC Jumpers will be certified to the guidelines in the ATEC test jumper certification program with the exception of the Jumpmaster qualification requirement.The Test Directorate Commander will review non-ATEC jumper’s qualifications, and recommendations forwarded to DTC for HUC approval to utilize these personnel during the test program prior to OT. The minimum number of jumps for non-ATEC jumpers will be 25 jumps. Non-ATEC personnel will not occupy aircraft stick positions that were not first cleared by ATEC jumpers.

Hazard Reduced Follow recommendations in the approved Safety Recommendation for OT.

Closed I E Med



Equipment Lowering line attachment ring failure upon releasing rucksack.

Personnel Injury, damage to harness attachment ring.

II D Med

Limit rucksack maximum weight to 80 pounds during mass tactical airdrops.Inspect MS70123 attachment ring for damage between airdrops.Install MS22020-1 attachment ring in fielded ATPS.


Closed II E Low



Test of ATPS from platforms without mannequin testing or technical evaluation.

Personnel Injured II D Med

Limit DTIII testing to C-130, C-17, CASA 212, UH-1, and UH-60 aircraft.

Gross aircraft weight of C-17 is limited to 400,000.


45. T-11 Harness,Canopy Release Assembly

Operation,Deployment sequence, Opening shock

Canopy Release opens prematurely

Personnel injured II D Med

The harness is designed in accordance with the current TSO standards, and all components were chosen to ensure adequate safety factor.The redesigned CRA was tested during DTIII and passed with a .96 probability with 90% level of confidence.


33

The risk management process for the table above was generated using ATEC Regulation 385-1 because it constitutes the Army’s standard risk management process. Figure 2.3-1 shows the risk identification number plotted on a risk severity matrix.

RISK SEVERITY MATRIX FOR T-11 PARACHUTISTS DURING MASS EXIT AT 400,000-lb GROSS AIRCRAFT WEIGHT (Ref. ATECR 385-1)

Hazard Analysis Tracking Numbers per T-11 Hazard Analysis Tracking List

Hazard ProbabilityFrequent Likely Occasional Seldom Improbable

A B C D E

Haz

ard

Seve

rity

CATASTROPHIC I18, 28, 29, 30, 32, 34, 35, 36,

37, 41, 42

CRITICAL II 27, 31, 33

3, 4, 5, 6,7,9, 16, 17, 19, 20, 21, 24, 25, 26, 40, 43, 44, 45

MARGINAL III 38 8, 10, 14, 39 2, 11, 15, 23

NEGLIGIBLE IV 1 22 12, 13OVERALL

RESIDUAL RISK LEVEL:

MEDIUM

Figure 2.3–1. Residual Risk To T-11 Parachutists After Completion of IGW Testing

This figure depicts the remaining residual risk for conducting T-11 mass exit airdrops from the C-17 at IGW, and will serve as the initial risk management baseline for the future planning of FSR activities. The table will be updated to include risk observed during FSR testing when future efforts are executed.

As a result of this analysis, the YTC test team recommends a Safety Confirmation be issued for the T-11 static line personnel parachute to allow a full paratrooper load to deploy from the C–17 at 400,000 lb. gross aircraft weight at the time of green light using the current approved formation geometry. Residual risk for this activity is Medium.

34

APPENDIX A. C–17 IGW AND FSR TEST CRITERIA

SECTION 3. APPENDICES

A. TEST CRITERIATable A–1. C-17 IGW/FSR Test Criteria

Item No.

Applicable Source Test Criteria Met/Not Met

1 Student Derived

Record empirical measurements of the wake/vortex pair that are generated by a single C–17 during standard training and tactical airdrop flight profiles, in a variety of atmospheric and terrain conditions

MET. Criterion is considered met when 143 total personnel airdrop profiles were successfully conducted, using LIDAR to record behavior of vortices and meteorological conditions.

2 Student Derived

Conduct statistical hypothesis testing of the Vortex Modeling Tool by incorporating empirical C–17 wake/vortex measurements in order to determine level of suitability in using the tool to aid in analysis of reduced formation geometry.

Partially MET. Criterion is partially met as data sets are still being reduced at the writing of this report. Project funding issues in 2014 and 2015 prevented further analysis to be completed.

3 Student Derived

Conduct comprehensive Vortex Modeling Tool model runs in varying GRF airdrop formations, atmospheric, and terrain conditions in order to analyze the risk of reducing formation spacing.

Not Tested. Current data reduction and modeling is still in process for this subtest.

4 Student Derived

Determine which factors significantly affect fuel requirements and gross aircraft weight

MET. Criterion is considered met because correlation and regression analysis led to an updated flight data sets from the IGW and FSR portions of testing.

5 Student Derived

Design a set of equations in a parametric model based on analogous historical flight models, as well as empirical flight data collected within the last year.

MET. Criterion was considered met when new equations from new training and validation data sets were successfully developed into a parametric model for fuel consumption. Validation of the model using statistical hypothesis testing was completed on the updated version of the model.

6 Student Derived

Provide an updated working example of the model in a typical mass exit airdrop environment

MET. Updated model provided in file named “FUDGE_Tool_Versions 1 and 2.xlsx”

7 Student Derived

Residual risk for deploying T-11 jumpers at increased gross weights up to 400,000 lb. shall not be more than current residual risk at 385,000 lb. (Medium).

Partially MET. Criterion for this subtest was considered met for up to 100 parachutists from a single

1

APPENDIX A. C–17 IGW AND FSR TEST CRITERIA

C–17 when risks for the C–17 IGW/FSR test program were assessed for the entire test effort, using AR 385–10 as a guide. No additional risks for up to 100 parachutists or aircrew were found when conducting mass exit operations at 400,000 lb. gross aircraft weight. Modified procedures for parachutists and aircrew are not required. FSR testing has not been completed and will be included in future documentation. Residual risk for deploying parachutists from the C-17 at 400,000 lb. is medium.

LEGENDGRF – Global Response ForceIGW – Increased Gross Weightlb. – poundUSAF – United States Air Force

2

APPENDIX B. C–17 IGW AND FSR REFERENCES

B. REFERENCES

1. Verification and Validation Report, Personnel Airdrop Optimization (PAO) Models for New Personnel Airdrop Platforms, U.S. Army Evaluation Center, July 2001

2. Draft Memorandum of Agreement, subject: Test Agency Agreement on Roles and Responsibilities for Completing C-17A Increased Gross Weight (IGW) and Reduced Formation Spacing (FS) Testing, December 2012

3. Memorandum For Vice Chief of Staff of the Army dated 23 February 2012, subject: Revalidation of C-17 Aircraft Airdrop Spacing and Aircraft Gross Weight During T-11 Parachute Operations.

4. Draft Failure Definition Scoring Criteria, C-17 Increased Gross Weight and Formation Spacing Reduction Study, December 2012.

5. Graduate Project Proposal, Masters of Science in Engineering Management, K. Allen, 4 May 2014.

6. FUDGE 1.0, Fuel Delivery Gross Weight Estimator, C-17A Globmaster Fuel Estimation Model for Personnel Mass Exit Operations, Produced for SIE 564, K. Allen, June 2014.

7. William B. Blake, Development of the C–17 Formation Airdrop Element Geometry, U.S. Air Force Research Laboratory, Wright – Patterson Air Force Base, Ohio 45433–7531, Journal of Aircraft Vo. 35, No. 2, March to April 1998.

8. Formation Airdrop Scaling Effects on Aircraft Wake/Vortex Formation and Interaction, Nicholas K. Borer, Timothy M. Barrows3, Diane M. Levine4, Lance A. Page, The Charles Stark Draper Laboratory, Cambridge, MA, 02130, Richard J. Benney, U.S. Army Soldier Research, Development, and Engineering Center, Natick, MA 01760.

3 Principal Member of the Technical Staff, 555 Technology Sq., MS 84, AIAA Member.4 Real-Time Embedded Software Engineer, 555 Technology Sq., MS 77.

1

APPENDIX C. ADITIONAL DATA

0 10 20 30 40 50 60 70 80240

260

280

300

320

340

360

380

400

420

440

vortex age (sec)

heig

ht (m

)

Height vs. Time

wakes_0423_010539_dec12.txtwakes_0423_011359_dec12.txtwakes_0423_012220_dec12.txtwakes_0423_012932_dec12.txtwakes_0423_013707_dec12.txtLinear Fit Slope = -1.9258

0 10 20 30 40 50 60 70 80240

260

280

300

320

340

360

380

400

420

440

vortex age (sec)

heig

ht (m

)

Height vs. Time

wakes_0423_010539_dec12.txtwakes_0423_011359_dec12.txtwakes_0423_012220_dec12.txtwakes_0423_012932_dec12.txtwakes_0423_013707_dec12.txtLinear Fit Slope = -1.5686

C-1


32.915 32.92 32.925 32.93 32.935 32.94 32.945 32.95 32.955 32.96 32.965-114.38

-114.378

-114.376

-114.374

-114.372

-114.37

-114.368

-114.366

latitude

Vortex Tracks

long

itude

wakes_0423_010539_dec12.txtwakes_0423_011359_dec12.txtwakes_0423_012220_dec12.txtwakes_0423_012932_dec12.txtwakes_0423_013707_dec12.txt

0 1000 2000 3000 4000 5000 6000-50

0

50

100

150

200

250

300

350

400

XLOC

Crosstrack Offset vs. X Loc

Cro

sstra

ck O

ffset

(m)

wakes_0423_010539_dec12.txt, CW -11.9186wakes_0423_011359_dec12.txt, CW -12.6271wakes_0423_012220_dec12.txt, CW -12.3058wakes_0423_012932_dec12.txt, CW -11.6553wakes_0423_013707_dec12.txt, CW -11.4017

C-1


C-1

APPENDIX D. C–17 IGW AND FSR ABBREVIATIONS

D. ABBREVIATIONS

ABNSOTD – U.S. Army Airborne and Special Operations Test DirectorateADS – Air Delivery SystemsAEC – U.S. Army Evaluation CenterAFIT – Air Force Institute of TechnologyAGL – above ground levelAMC – Air Mobility CommandATEC – U.S. Army Test and Evaluation CommandATF – Airborne Test ForceATPS – Advanced Tactical Parachute SystemCE – Combat EquipmentCRA – canopy release assemblyDOT&E – Director of Operational Test and EvaluationDT – Developmental TestDTC – U.S. Army Developmental Test CommandDZ – drop zoneFDSC – Failure Definition Scoring CriteriaFSR – Formation Spacing Reductionft. – footFt. – Fortft2 – square footGPS – Global Positioning SystemGRF – Global Response ForceIAW – in accordance withIGW – Increased Gross Weightin. – inchIVTS – Improved Vehicle Tracking SystemKIAS – Knots Indicated Air SpeedKTM – Kineto Tracking Mountlb. – poundm – meterm/s – meters per secondMCCP – Monte Carlo Centerlining ProgramMHz – megahertzMOS – Military Occupational SpecialtyNC – North CarolinaNSRDEC – U.S. Army Natick Soldier Research, Development and Engineering CenterOSD – Office of the Secretary of DefenseOT – Operational TestPERT – Program Evaluation and Review TechniquePI – Point of ImpactPMI – Project Management InstitutePM–SCIE – Program Manager-Soldier Clothing and Individual EquipmentPQT – Production Qualification Test

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APPENDIX D. C–17 IGW AND FSR ABBREVIATIONS

PTMs – Portable Tracking MountsPVC – polyvinyl chlorideRAWIN – Radio WindsondeROM – Rough Order of MagnitudeSAMS – Surface Air Measurement SystemSME – Subject Matter ExpertSOMTE – Soldier, Operator, Maintainer, Test and EvaluationSOW – Scope of WorkT–11R – T–11 ReserveTES – Test and Evaluation SquadronTGW – Total Gross WeightTIR – Test Incident ReportTM – training manualTP – Test ParachutistTPWG – Test Program Working GroupTRI – Technical Rigger InspectionTSPI – Time Space and Position InformationUSAF – United States Air ForceUTC – Coordinated Universal Timeyd. – yardsYPG – Yuma Proving GroundYTC – Yuma Test Center

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SIE909_Masters_Project_Allen_Deliverable3_FINAL_Revised 25 April

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