Relevant Design Requirements - Civil Aviation Safety … · Relevant Design Requirements Compliance should have been found to FAR25.1438 – pressurisation system ... testing must

Relevant Design Relevant Design RequirementsRequirements

Design ApprovalsDesign Approvals

Topic Topic –– 11

Design Standards/requirementsDesign Standards/requirements

Certification Basis from TCDSCertification Basis from TCDS

Some aircraft have multiple TCs

Identify TCDS from CASA TAC

Relevant Design RequirementsRelevant Design Requirements

Sub set of Design Standard such as FAR Sub set of Design Standard such as FAR 23, 25 etc. at the relevant amendment 23, 25 etc. at the relevant amendment statusstatus

Specific to the modification or repairSpecific to the modification or repair

Other aspects Other aspects

Case StudyCase Study

Repair of bleed air ductRepair of bleed air ductFAR 25 aircraftFAR 25 aircraft––Not part of engine Not part of engine –– not in not in engine IPCengine IPC

––66”” long 321 Stainless steel elbowlong 321 Stainless steel elbow––Chafing damage Chafing damage –– right throughright through

Case study Case study -- repairrepair

Prepare a weld patch using 331 ssPrepare a weld patch using 331 ssTig weld using 331 ss rod per OEM processTig weld using 331 ss rod per OEM processDress weld beadDress weld beadCarry out FPI per OEM processCarry out FPI per OEM processCheck to ensure adequate clearance so that Check to ensure adequate clearance so that chafing does not recur chafing does not recur –– repetitive repetitive inspectioninspection

Design requirementsDesign requirements

25.603 Materials 25.603 Materials –– addressed by using addressed by using appropriate materialsappropriate materials

25.605 Fabrication methods 25.605 Fabrication methods –– Tig welding Tig welding per OEM process per OEM process –– FPI after weldingFPI after welding

25.1529 25.1529 –– ICA has been includedICA has been included

Elimination processElimination process

FAR 25 Design standards FAR 25 Design standards –– Sub parts Sub parts –– AA-- applicabilityapplicability–– BB-- flightflight–– CC--structuresstructures–– DD-- Design and ConstructionDesign and Construction–– EE-- PowerplantPowerplant–– FF-- EquipmentEquipment–– GG-- Operating limitsOperating limits

Elimination processElimination process

FAR 25 Design standards FAR 25 Design standards –– Sub parts Sub parts –– AA-- applicabilityapplicability–– BB-- flightflight–– CC--structuresstructures–– DD-- Design and ConstructionDesign and Construction–– EE-- PowerplantPowerplant–– FF-- EquipmentEquipment–– GG-- Operating limits Operating limits –– (ICA)(ICA)

Design and constructionDesign and construction

25.603 materials25.603 materials25.605 Fabrication methods25.605 Fabrication methods25.1529 ICA ( operating limits) 25.1529 ICA ( operating limits)

EquipmentEquipment

Electronic Electronic –– 25.143125.1431Vacuum Vacuum –– 25.143325.1433Pressurisation and pneumatics Pressurisation and pneumatics –– 25.143825.1438

PressurisationPressurisation

25.1438 Pressurisation and pneumatic 25.1438 Pressurisation and pneumatic systemssystems–– Pressurisation systemPressurisation system elements must be burst elements must be burst

pressure tested to 2 times pressure tested to 2 times ……..the maximum ..the maximum operating pressure.operating pressure.

–– Pneumatic systemPneumatic system elements must be burst elements must be burst pressure tested to 3 times the and proof pressure tested to 3 times the and proof pressure tested to 1.5 timespressure tested to 1.5 times

Pressurisation and pneumaticsPressurisation and pneumatics

What is the difference between What is the difference between pressurisation and pneumatics?pressurisation and pneumatics?

FAA AC 25FAA AC 25--2222

(b) The FAA considers the pneumatic system to include all air supply elements from the bleed port on the engine to the pressure regulating and shutoff valve. Pressurization system elements are all other elements in the air distribution system.

Relevant Design RequirementsRelevant Design Requirements

Compliance should have been found toCompliance should have been found to

FAR25.1438 FAR25.1438 –– pressurisation systempressurisation system25.60325.60325.60525.60525.152925.1529

Compliance to ICA should be there in all Compliance to ICA should be there in all alterationsalterations

Relevant design requirement Relevant design requirement identificationidentification

Follow top down elimination approachFollow top down elimination approach

Need familiarity and experienceNeed familiarity and experience

Basis for DA requirement for major modsBasis for DA requirement for major mods

First Aid Box InstallationFirst Aid Box Installation ( decade old case study)( decade old case study)

Relevant design requirementsRelevant design requirements

Install with 3 AN3 boltsInstall with 3 AN3 boltsWet installation into the honeycomb Wet installation into the honeycomb structurestructureStraps made of 2024 Straps made of 2024 –– T3 ssT3 ssLog book entry Log book entry

Design and ConstructionDesign and Construction

25.785 Seats, Berths, safety belts and 25.785 Seats, Berths, safety belts and harnessesharnesses25.785 (k) Each projecting object that would 25.785 (k) Each projecting object that would injure persons seated or moving about the injure persons seated or moving about the airplane in normal flight must be paddedairplane in normal flight must be padded

ImplicationsImplications

Non compliance had affected design Non compliance had affected design features features Compliance statement is not an after Compliance statement is not an after thoughtthoughtThe first aid box was reThe first aid box was re--located on 6 aircraftlocated on 6 aircraft

Conclusion Conclusion -- 11

Identification of relevant design requirement Identification of relevant design requirement is criticalis criticalPart of CAR 35 regulatory compliancePart of CAR 35 regulatory complianceFollow the method of eliminationFollow the method of eliminationRead the relevant ACsRead the relevant ACsFamiliarise with the design standardsFamiliarise with the design standards



Other regulatory requirementsOther regulatory requirements

Other requirementsOther requirements

Case studyCase studyCargo compartment lighting Cargo compartment lighting –– FAR25 FAR25 Old light fitting with metal mesh protector replaced Old light fitting with metal mesh protector replaced with LED fittingwith LED fittingLED fitting is OEM suppliedLED fitting is OEM suppliedMod compliant to all the TCDS based Mod compliant to all the TCDS based requirementsrequirementsAWI points out that there should be a metal mesh AWI points out that there should be a metal mesh

Retrospective requirementsRetrospective requirements

90.140 Cargo and baggage compartment lighting(2) If the aircraft has lighting within a cargo or baggage compartment, the lamps:(a) must be protected against the possibility of accidental damage; and(b) must be insulated so that any baggage placed adjacent to the lamp is not subjected to excessive heat.

Regulatory requirementRegulatory requirement

One has to comply with all regulationsOne has to comply with all regulations

Requirements can be scattered Requirements can be scattered

Casa requirementCasa requirement

90.005 Purpose of PartThis Part sets out airworthiness requirements for an aircraft that are

in addition to:(a) the type certification basis for the aircraft; and(b) any requirements for the issue of a certificate of airworthiness for the aircraft under Part 21.

CASA requirementsCASA requirements

Part 21Part 21 Certification and Certification and airworthiness requirements for aircraft and airworthiness requirements for aircraft and partsparts

Conclusion 2Conclusion 2

All approvals under CAR35 should address All approvals under CAR35 should address CASR Part 90 requirementsCASR Part 90 requirements

New regulation or an exemption will New regulation or an exemption will address this confusionaddress this confusion



Other information in TCDSOther information in TCDS

Bell 430 Bell 430 --Notes in TCDSNotes in TCDSNOTE 8 The model 430 helicopter employs electronic engine controls, commonly named Full Authority Digital Engine Controls (FADEC) and is recognized to be more susceptible toElectromagnetic Interference (EMI) than rotorcraft that have only manual (nonelectronic)

must either be qualified to an FAA acceptable standard or tested at the time ofinstallation for interference to the FADEC. This type of testing must employ the particular FADEC’s diagnostic techniques and external diagnostic techniques. The testprocedure must be FAA approved.

Certification BasisCertification Basis

Certification Basis. FAR 21.29 and FAR Part 27 dated February 1, 1965, including Amendments 27-1through 27-8.FAR Part 29 dated February 1, 1965, para. 29.903(b), for Category “A” engineisolation.Special Conditions for Agusta Model A109 helicopter No. 27-54-EU-17, issued on June 26, 1973.

Certification Basis from TCDSCertification Basis from TCDSCertification Basis FAR Part 29 dated February 1, 1965, (Transport Category A & B) amendment 29-1through 29-9 plus the following:Amendment 29-10 29.997;Amendment 29-11 29.1401FAA exemption no. 2789, FAR 29.811 (h) (l) and FAA exemption no. 4395, FAR 29.855 (a) and portions of 29.855 (d). FAA Exemptions 2789 and 4395 pertained tothe model 222 series helicopters;

Certification BasisCertification BasisCertification Basis. FAR 21.29 and FAR Part 27 dated February 1, 1965, including Amendments 27-1through 27-8.FAR Part 29 dated February 1, 1965, para. 29.903(b), for Category “A” engineisolation.Equivalent safety in lieu of compliance shown for:-FAR 27.1189, re shutoff means-FAR 27.1305(d), re fuel quantity indicator for A109A up to S/N 7165.-

Conclusion Conclusion -- 33

Review the TCDS and include or exclude Review the TCDS and include or exclude requirementsrequirements



Alteration of TSO compliant itemsAlteration of TSO compliant items

Modification of TSO partModification of TSO partFAA order 8150.1B para 20 c. The modifier should permanently obliterate TSO identification on the original manufacturer’s nameplate when

the modified article cannot be demonstrated to continue to meet the requirements of the original TSO. These types of modified articles are no longer approved for

installation in the original aircraft type design. A separate approval must be obtained as part of the aircraft type design


Does TSO constitute a design requirement?Does TSO constitute a design requirement?

Use TSO as the design requirement for Use TSO as the design requirement for TSO compliant items.TSO compliant items.

Implications for large TSOed items such as Implications for large TSOed items such as APU, IDG and several other equipmentsAPU, IDG and several other equipments



Alterations and ADsAlterations and ADs

No policy or advisory material from CASANo policy or advisory material from CASA

AD/LYC/117 crank shaft AD/LYC/117 crank shaft replacementreplacement

Requirement: 1. If Table 5 of Lycoming MSB No. 569A dated 11 April 2006 lists the crankshaft SN, replace the affected crankshaft with a crankshaft that is not listed in Table 5 of MSB No. 569A.

iii) No later than 12 years from the time the crankshaft first entered service .

AD implicationsAD implications

AD identifies a set of crank shafts that are AD identifies a set of crank shafts that are unsafe. Are they safe to repair?unsafe. Are they safe to repair?

The AD identifies a set of safe crank shafts. The AD identifies a set of safe crank shafts. Are they safe to repair?Are they safe to repair?

AD/LYC/103 Magneto coupling AD/LYC/103 Magneto coupling inspectioninspection

Compliance: 1. Within 10 hours TIS from the effective date of this directive and thereafter at intervals not to exceed 250 hours TIS.

AD statementAD statement

Products under the maintenance regime of Products under the maintenance regime of an AD are criticalan AD are criticalProducts identified for replacement by an Products identified for replacement by an AD may be criticalAD may be critical

AD/B737/73AD/B737/73

The FAA requires reinforcement of the overhead stowage bins and modification of the overhead stowage bin components. Testing has demonstrated that the bins are not able to withstand ultimate load at the current maximum allowable weight levels.

AD/B737/92AD/B737/92

Boeing has advised that a change to the fireproof insulation on the thrust reverser fan duct firewall to decrease aircraft weight has resulted in the firewall not meeting certification requirements.

AD/B737/112AD/B737/112

Service experience has revealed a possible fault in the subject actuators which could prevent the pilot from shutting off the fuel to the engine following an engine failure and/or fire. This Directive has been raised to replace the effected components with serviceable items.FAR 33.75…(d) Loose the capability of being shut down…

CASR 39.004CASR 39.004

ADs emerge from regulatory nonADs emerge from regulatory non--compliance, mostly related to certification or compliance, mostly related to certification or very rarely due to improper maintenance or very rarely due to improper maintenance or manufacture.manufacture.

This could imply that the original finding of This could imply that the original finding of compliance was inadequate. compliance was inadequate. And hence the regulator need to be involved And hence the regulator need to be involved in AMOC in AMOC

CASR 39.004CASR 39.004

This implies that the standard means of This implies that the standard means of finding compliance per CAR35 are finding compliance per CAR35 are inadequateinadequate

There is some secret information related to There is some secret information related to the stuff up, and hence the regulator need to the stuff up, and hence the regulator need to be involved in AMOCsbe involved in AMOCs

Alterations and ADsAlterations and ADs

When altering AD affected areasWhen altering AD affected areas

Declare the alteration as major and contact Declare the alteration as major and contact CASA because if the regular ways of finding CASA because if the regular ways of finding compliance is adequate, there would not compliance is adequate, there would not have been an AD, typicallyhave been an AD, typicallyThere is some secret information with the There is some secret information with the regulator?regulator?


Contact CASA when the alteration has Contact CASA when the alteration has potentially affects AD compliance.potentially affects AD compliance.

ConclusionConclusion

Design approval procedures have been Design approval procedures have been ahead of regulationsahead of regulations

Compliance finding declaration through form Compliance finding declaration through form 979, design coordination, approved 979, design coordination, approved exposition section etc.exposition section etc.

Conclusion SummaryConclusion Summary

Identify design requirements through top Identify design requirements through top down elimination processdown elimination processAdditional requirements of Part 90Additional requirements of Part 90Other requirements and exemptions per Other requirements and exemptions per TCDSTCDSComply with TSO requirementsComply with TSO requirementsReview impact of alterations on ADsReview impact of alterations on ADs

CASA and RegulationsCASA and Regulations

http://www.austlii.edu.au/au/cases/cth/AATAhttp://www.austlii.edu.au/au/cases/cth/AATA/2011/181.html/2011/181.html

Regulations and PolicyRegulations and Policy

http://www.austlii.edu.au/au/cases/cth/AATA/2011/181.html

http://www.austlii.edu.au/au/cases/cth/AATA/2011/181.html

Final ConclusionFinal Conclusion

Is it Design RequirementsIs it Design RequirementsOrOr

Certification basisCertification basis

OrOr

Design Approval Basis for AlterationsDesign Approval Basis for Alterations

Relevant Design Requirements - Civil Aviation Safety … · Relevant Design Requirements Compliance should have been found to FAR25.1438 – pressurisation system ... testing must

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