October 26, 2009 Presented by: Dr. Robert Vaughan Chief Technology Branch Structures & Materials Division Aviation Engineering Directorate Aviation and Missile Research, Development and Engineering Center Presented to: DoD Maintenance Symposium “Understanding and Combating Aging” Phoenix Convention Center, Phoenix, AZ UNCLASSIFIED UNCLASSIFIED US Army Aviation Helicopter Dynamic Components Approved for public release; distribution unlimited. Review completed by the AMRDEC Public Affairs Office (10/09/09 and FN4254 ).
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Aviation and Missile Research, Development and Engineering Center
Presented to:DoD Maintenance Symposium
“Understanding and Combating Aging”Phoenix Convention Center, Phoenix, AZ
UNCLASSIFIED
UNCLASSIFIED
US Army Aviation Helicopter Dynamic Components
Approved for public release; distribution unlimited. Review completed by the AMRDEC Public Affairs Office (10/09/09 and FN4254 ).
UNCLASSIFIED
UNCLASSIFIED
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CRACKED H-47 SWASHPLATE ROTATING RING
In 2004 routine maintenance discovered a MH-47E Forward Rotating Ring with fatigue cracks during overhaul. This was a first time anomaly. Subsequent inspections have found that ~15% of the Swashplates inspected have these micro cracks near the bearing surface.
Testing, Analysis, and Inspections used to minimize the risk associated with fatigue cracking in the swashplate.
On 30 May 2009, failure of both drive link scissors on AH-64D Apache Aircraft xxx occurred during operational usage.
On 2 Jun 2009, a single knuckle lug of a single TR drive link scissors failed on AH-64D Apache Aircraft xxx during operational usage .
On 8 Jun 2009, a single lug of a single TR drive link scissors failed at the swashplate interface on AH-64D Apache Aircraft xxx during operational usage.
Failure
Failure
Failure
Failure Three failures of the TR drive links were discovered this spring.
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Erosion of Engine Compressors
• T700 Engine Stage 1 Blisk Erosion– Erosion is caused by continuous
ingestion of small hard particles such as sand into engine
– Erosion degrades compressor efficiency and leads to reduced engine performance
RIMFIRE inspection at Corpus Christi Army Depot
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Compressor Erosion Trending
Percentage of Engine/Module Removals Due to Compressor Erosion
Percentage of Engine Removals Due to Burns, Oxidation and Cracks of Stage 1Turbine Blades
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Chinook Rotor Systems
Zone J – OD Outside of Limits
– 34.7% rejected due to this condition
Hinge Pin Analysis
RIMFIRE Reports
Zone J
DMWR Limit = 4.5090 inches min.
Average = .0102” under limit
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Chinook Rotor Systems
• 294 Hinge Pins Inspected in RIMFIRE Project
• 121 Rejected by CCAD• 41.2% Reject Rate
Hinge Pin Analysis
RIMFIRE Reports
* Some parts had more than 1 reason for rejection.
Reasons for Rejection Frequency *
1 Zone J - OD Out of Limits 102
2 Zone H - OD Out of Limits 6
3 Zone B - Scoring 4
4 Zone D - Nicks/Wear 3
5 Zone D - Stained 2
6 Misc. Conditions 7
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Black Hawk Rotor Systems
• Zones A & R Damage– 14% of Shafts rejected due to
Chipping/Gouging/Denting in these Zones
RIMFIRE Reports
Zone R
Zone A
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Black Hawk Rotor Systems
• 150 Shaft Extensions Inspected in RIMFIRE Project
• 21 Rejected by CCAD• 14% Reject Rate
Main Shaft Extension Analysis
RIMFIRE Reports
* Some parts had more than 1 reason for rejection.
Reasons for Rejection Frequency *1 Zone R Damage 122 Zone T Damage 73 Zone A - Spline Damage & Wear 44 Zone H - Chipped 15 Zone P - Chipped 1
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Apache Rotor Systems
Zone L
– 37.4% of Pitch Housings did not pass initial DMWR inspection due to incorrect bonding prep.
Pitch Housing Analysis
RIMFIRE Reports
Zone L
This is a repairable condition per DMWR
Zone K
– 32.8% of washers in this zone were debonded and did not pass initial DMWR inspection.
– 24.6% of washers in this zone were missing and did not pass initial DMWR inspection.
Zone K
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Apache Rotor Systems
• 329 Pitch Housings Inspected in RIMFIRE Project
• 191 Failed Initial DMWR Inspection Criteria
• 58.1% Reject Rate†
• All -15 Pitch Housings with over 300 hours are being Retired at Depot due to 1204 Hour Life Limit.
Pitch Housing Analysis
RIMFIRE Reports
* Some parts had more than 1 reason for rejection.† Prior to any repairs
1 Zone L - Bonding Prep Incorrect2 Zone K - Debonded3 Zone K - Missing Washers4 Zone C Bushing Wear5 Zone F Bushing Wear6 Zone E Liner & Shim Debonding/Wear7 Zone G Bushing Wear8 Zone A Bushing Wear9 Dents & Gouges10 Scored/Scratched
Data collected between 2/5/2005 and 7/16/2007
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Apache Rotor Systems
Zone C - Wear
– 15.5% of Pitch Housings failed initial DMWR inspection due to inner diameter wear of bushing exceeding max. limit.
Pitch Housing Analysis
RIMFIRE Reports
DMWR Limit = 2.507 in. maxMean Wear = 0.0028 over limit
This is a repairable location.
Zone CFr
eque
ncy
0.0090.0060.0030.000-0.003
10
8
6
4
2
0
Mean 0.002825StDev 0.002807N 36
Normal Histogram of Zone C
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Apache Rotor Systems
Zone F - Wear
– 14% of Pitch Housings failed initial DMWR inspection due to inner diameter wear of bushing exceeding max. limit.
Pitch Housing Analysis
RIMFIRE Reports
DMWR Limit = 2.507 in. maxMean Wear = 0.0014 over limit
This is a repairable location.See Chart 4 for Location
Zone FFr
eque
ncy
0.0030.0020.0010.000-0.001
9
8
7
6
5
4
3
2
1
0
Mean 0.001428StDev 0.001048N 32
Histogram of Zone FNormal
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Apache Rotor Systems
Zone B - Wear
– 37.5% of assemblies failed initial DMWR inspection due to inner diameter wear exceeding max. limit.
RIMFIRE Reports
DMWR Limit = 1.628 in. max
Mean Wear = 0.077 over limit
Lower Shoe Assembly Analysis
Zone B
Zone BFr
eque
ncy
0.270.180.090.00-0.09-0.18
25
20
15
10
5
0
Mean 0.07688StDev 0.1135N 40
Histogram of Zone BNormal
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Apache Rotor Systems
• 48 Lower Shoe Assemblies Inspected in RIMFIRE Project
• 29 Failed Initial DMWR Inspection Criteria
• 60.4% Reject Rate†
Lower Shoe Assembly Analysis
RIMFIRE Reports
* Some parts had more than 1 reason for rejection.† Prior to any repairs
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Apache Rotor Systems
Zone C - Wear
– 25% of assemblies failed initial DMWR inspection due to inner diameter wear exceeding max. limit.
RIMFIRE Reports
DMWR Limit = 0.691 in. max
Mean Wear = 0.067 over limit
Lower Shoe Assembly Analysis
Zone C
Zone C
Freq
uenc
y
0.240.160.080.00-0.08-0.16
30
25
20
15
10
5
0
Mean 0.06699StDev 0.1037N 40
Histogram of Zone CNormal
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Apache Rotor Systems
• 106 Hub Subassemblies Inspected in RIMFIRE Project
• 45 Failed Initial DMWR Inspection Criteria
• 42.5% Reject Rate†
Hub Subassembly Analysis
RIMFIRE Reports
* Some parts had more than 1 reason for rejection.† Prior to any repairs
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Apache Rotor Systems
Zone G - Wear
– 15.1% of Hubs failed initial DMWR inspection due to inner diameter wear exceeding max. limit.
Hub Subassembly Analysis
RIMFIRE Reports
DMWR Limit = 9.0475 in. max
Mean Wear = 0.005 over limit
GZone G
Freq
uenc
y
0.0080.0070.0060.0050.0040.0030.002
4
3
2
1
0
Mean 0.005041StDev 0.001388N 15
Histogram of Zone GNormal
Pitting / Corrosion
– 12.3% of Hubs failed initial DMWR inspection due to pitting or corrosion