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Regulatory Article 5722
RA 5722 - Propulsion Integrity Management
Rationale
The aim of Propulsion Integrity Management is to counter the threats to Propulsion
Integrity (PI) throughout the life of the aircraft or system, across organizational,
process and responsibility boundaries; ensuring risks to airworthiness are Tolerable
and As Low As Reasonably Practicable (ALARP). Propulsion Integrity Management
requires a planned programme of measures.
Contents
5722(1): Propulsion Integrity Management
5722(2): Establishing Propulsion Integrity
5722(3): Sustaining Propulsion Integrity
5722(4): Validating Propulsion Integrity
5722(5): Recovering Propulsion Integrity
5722(6): Exploiting Propulsion Integrity
Regulation
5722(1)
Propulsion Integrity Management
5722(1) The Type Airworthiness Authority (TAA) shall manage all
aircraft to ensure an acceptable and demonstrable level of
PI.
Acceptable
Means of
Compliance
5722(1)
Propulsion Integrity Management
1.
RA5722 should be applicable to all aircraft types, regardless of procurement
model.
2.
Where threats to PI are identified, airworthiness risks should be reduced to
tolerable and ALARP.
3.
Measures should be taken to counter threats to PI, using an appropriate
management framework incorporating a strategy document, management plan and a
working group.
Guidance
Material
5722(1)
Propulsion Integrity Management
4.
PI may be compromised, at any stage of an aircraft life cycle, by a number of
threats which may include component degradation, change in usage, unmonitored
operation, fatigue, creep, overload and lack of configuration control. This is not a
comprehensive list and additional guidance is contained in the PI Management
handbook available on the MAA website on both the Internet and Defence Intranet.
5.
This RA specifies those activities required to achieve and maintain PI for all
aircraft operated within the Military Air Environment, from inception to eventual
disposal. This RA is based on the Establish-Sustain-Validate-Recover-Exploit
(ESVRE) approach, this method may be used by the Project Team (PT) to manage
and counter the threats to PI. All PI management activity is to be acceptable to the
TAA given their Type Airworthiness Management responsibilities (iaw RA1015) and
demonstrable to the MAA in the form of documented analysis and records.
Regulation
5722(2)
RA 5722 Issue 6
Establishing Propulsion Integrity
5722(2) The TAA shall ensure that Propulsion Integrity is
established.
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Regulatory Article 5722
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Acceptable Establishing Propulsion Integrity
Means of
6.
A Propulsion Integrity Strategy should be established as part of the Through
Compliance Life Management Plan (TLMP). This Strategy should be:
a.
Communicated to stakeholders through the Propulsion Integrity Strategy
5722(2)
Document (PISD).
b.
Managed through the Propulsion System Integrity Management Plan
(PSIMP).
c.
Implemented through a biannual Propulsion System Integrity Working
Group (PSIWG):
(1)
The PSIWG should be chaired by the TAA or the holder of a
delegated Letter of Airworthiness Authority (LoAA) at least of an OF4 or
B2.
(2)
Key PI Stakeholders should be considered as the core
membership of the PSIWG and other stakeholders may be invited as
necessary.
7.
Certification and Qualification details should be confirmed by the Design
Organization (DO).
8.
Critical components should be identified, lifed and authorized by the TAA.
9.
Component lives (Critical and Non-Critical) and exchange rates should be
authorized by the TAA.
10. PI risks should be captured within the platform Air Safety Management System
(ASMS).
Guidance
Material
5722(2)
Establishing Propulsion Integrity
PISD
11. The PISD is the means by which the TAA promulgates PI strategy and details
the intended approach to through life PI management activities that will underpin
airworthiness. It also serves as a record of significant PI issues which occur over the
life of the Propulsion System and provides an audit trail of significant PI decisions.
This document will form part of the project TLMP and the associated Air System
Safety Case.
PSIMP
12. The PSIMP forms part of the overall PI strategy and is to document all of the PI
management activities detailed in the PISD. The PSIMP will provide the time line for
routine/scheduled PI activities and may also be used to track recovery action. The
PSIMP is broken down into individual programme, recurring and one-off activities, key
milestones and decision points, as appropriate to the position of the aircraft type in the
project life cycle. It will be owned by the PT and made available to all PI stakeholders.
PSIWG
13. A PSIWG will be established for each Propulsion System and it will provide a
forum to implement and review PI activity detailed in the PSIMP. The PSIWG
provides the opportunity for stakeholders to discuss threats to PI and to allow the
Chair to understand the risks associated with these threats. The PSIWG is to be held
biannually and timed to allow onward reporting to the Platform Safety Panel (PSP) and
Platform Safety Working Group (PSWG). PSIWGs will be initiated by the PT at an
appropriate time prior to introduction to service and in consultation with MAA-CertMPS. In multi-national projects, multi‑national forums may be established to progress
PI issues common to the partner nations. However, it is likely that a UK-only PSIWG
will also be necessary once the aircraft enters service in order to progress national
issues associated with UK configuration, usage and operating practises and PI
requirements. Although executive airworthiness responsibility rests with the TAA,
there are a number of stakeholders in PI management (see Table 1) who can
contribute to the PI decision-making process.
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Guidance
Material
5722(2)
Regulatory Article 5722
Table 1. Table of PSIWG Key Stakeholders/Other Stakeholders.
Key Stakeholders
TAA or LoAA holder (at least OF4 or B2)
DO
PT Desk-level officers responsible for PI
Continuing Airworthiness Management
Organization
Prime Supporting Contractors
Front Line Command (FLC)
Platform Safety Manager
Commodities PT (for Auxillary Power
Unit)
Other Stakeholders
Independent propulsion system integrity
advisors
Requirement Managers
Engineering Development and
Investigation Team/Technical Support
Services (or equivalent
Stn/Ship/Unit Engineering/Aircrew
Aircraft Repair Organizations
Other regulatory authorities for the same
aircraft type
Original Equipment Manufacturers
Civilian Aviation Authority - for Military
Registered Civil Owned aircraft
Multi-National Management Agencies
(e.g. NETMA, OCCAR)
Release to Service Authority
DE&S Airworthiness Team (DAT)
MAA-Cert
Certification and Qualification
14. The integrity of a Propulsion System is established during the design and
manufacture of that system. The subsequent certification of the Propulsion System
assures the integrity of the Propulsion System for all anticipated flight conditions,
throughout the flight envelope.
15. All new UK military registered Air Systems, and their associated Propulsion
Systems, require certification in accordance with the Military Air Systems Certification
Process (MACP), as defined within ►RA 5810◄. The MACP is also applicable to all
Major Changes to the Type Design of in-service Propulsion Systems. The Propulsion
System certification requirements mandated by the MACP are contained within Def
Stan 00-970 Part 11.
16. Where the Propulsion System of a legacy platform has been civil-certified or
certified to an alternative airworthiness code, the TAA will need to be assured that the
certification basis used in that instance was appropriate for the intended military
operation of the Propulsion System and that any specific military requirements not
captured by the original certification basis, have been mitigated/addressed
accordingly.
17. During all certification activities, it is recommended that the Integrity
Management requirements of this RA be considered and that reference to the
certification and qualification evidence, as and when it becomes available, is captured
within the PISD.
18. The certification and qualification evidence that demonstrates the integrity of the
Propulsion System will be detailed in the Air System Safety Case in support of the
Release to Service and is to be maintained throughout the operational life of the
Propulsion System. Through-life activities such as repairs, modifications or changes
in usage or configuration may invalidate the original certification and qualification
evidence. These activities may prompt re-examination of the original design
assumptions and further establishing activities to counter threats to PI may be
required. Consideration may be given to develop this evidence to reflect the UK
military ‘as-flown’ usage and configuration as it matures and potentially diverges from
any ‘multi-national’ or ‘off-the-shelf’ baseline. Such activities may include development
testing, changes in operating condition, usage, configuration, unexpected failure
modes or deterioration.
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Regulatory Article 5722
Guidance
Material
5722(2)
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Critical Engine Components
19. A critical engine component is one which is required to achieve and maintain a
high degree of integrity, as its failure has been identified, through failure analysis, as
having the potential to result in a hazardous engine effect. Hazardous engine effects
are those which have been defined by the European Aviation Safety Agency (EASA)
within the Certification Specification for Engines and are regarded as:
a.
Non-containment of high-energy debris.
b.
Concentration of toxic products in the Engine bleed air for the cabin
sufficient to incapacitate crew or passengers.
c.
Significant thrust in the opposite direction to that commanded by the pilot.
d.
Uncontrolled fire.
e.
Failure of the Engine mount system leading to inadvertent Engine
separation.
f.
Release of the propeller by the Engine (if applicable).
g.
Complete inability to shut down the Engine.
20. The DO is required to identify the critical components contained within the
Propulsion System and provide appropriate life management details. The TAA may
accept and authorize the DO’s recommendations and promulgate the lifing within the
Aircraft Document Set (ADS).
Component Lifing
21. Where condition monitoring cannot anticipate the failure of a component, a life
will need to be formulated as required by Def Stan 00-970, Part 11. Lives of
components need to be proposed to the PT by the DO or an approved competent
organization (RA1005). Consideration is also to be given to shelf, storage and
inhibited lives of components.
22. The conversion of actual usage into the common currency of reference cycles is
achieved through the use of exchange rates. Instances where the Propulsion System
has twin (or multiple) populations (’fleets within fleets’), each exchange rate will be
managed separately.
23. The component lives and exchange rates proposed by the DO or competent
organization will be verified for compliance to the minimum standards prior to formal
approval. Authority for their approval and promulgation is vested in the TAA. In
addition, PTs may promulgate component lives and exchange rates in the ADS.
24. The Statement of Operating Intent (SOI) is the means by which the future
operating intent for a particular aircraft type and major mark are conveyed formally to
the DO by the MOD. The Statement of Operating Intent and Usage (SOIU) replaces
the SOI when the aircraft has accumulated sufficient in-service usage data.
Consideration will be given to how initial/changing sortie profiles and standard
operating procedures impact upon the Propulsion Systems of an aircraft.
Capturing PI risks
25. Within an Air System Safety Case and through the introduction of an ASMS, it is
necessary to assess the hazards that a Propulsion System can present to a platform
and to ensure the risks posed by these hazards are Tolerable and ALARP (see
RA1220 Project Team Airworthiness and Safety). These risks will be reported up to
the platform level hazard analysis. For further information on Engine Hazardous
effects see Def Stan 970 Part 11
Regulation
5722(3)
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Sustaining Propulsion Integrity
5722(3) The TAA shall monitor, measure and counter threats in order
to sustain PI.
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Acceptable
Means of
Compliance
5722(3)
Regulatory Article 5722
Sustaining Propulsion Integrity
26. PI should be reviewed and managed through the bi-annual PSIWG process
and reported to the appropriate Airworthiness Management Group (AMG).
27.
Propulsion system configuration control should be managed.
28.
The following data should be accurately captured and recorded by the users:
29.
a.
Usage data.
b.
Failure data.
Health monitoring should be carried out by the users.
30. Support Policy Statement (SPS) and Maintenance Schedules should be
managed and maintained.
31.
Obsolescence should be managed.
32. The Propulsion system should be included in the Ageing Aircraft Audit
(RA5723: Ageing Aircraft Audit).
33. Any unmitigated or unquantified airworthiness risks should be identified to the
PSP/PSWG.
34.
Guidance
Material
5722(3)
The PSIWG should endorse the strategies and plans to mitigate the risks to PI.
Sustaining Propulsion Integrity
PSIWG
35. The objectives of a PSIWG are to:
a.
Enable the management of PI to be ratified and assessed in accordance
with MOD propulsion regulation and reported upward to the relevant AMG.
b.
Review PI management processes commensurate with the aircraft’s
position in its lifecycle, taking into account projected usage and known risks.
Configuration Control
36. Failure to maintain Propulsion System configuration control may have an
adverse effect on PI and airworthiness. During its operational life the Propulsion
System configuration of in-service aircraft may diverge from the as‑built standard, as
individual aircraft and equipment are subject to: Service Instructions (Technical),
damage, repairs, obsolescence, modifications and mid-life updates; this is not a
comprehensive list. All critical components require to have a record of consumed life
that include details of component installation in module, engine (or accessory) and
aircraft. The PT may contract out configuration control management but the TAA
retains the responsibility to ensure that a configuration control system is maintained in
service.
Data Collection
37. The DO requires in-service, as flown usage parameter data (e.g. Turbine Blade
Temperature and Engine Speed N1) in order to monitor and evaluate component lives
and Maintenance Schedules.
38. PTs also require in-use failure data in order to ascertain actual failure rates.
This will allow Maintenance Schedules to be implemented to extend Mean Time
Between Failures, or to enable the component to be replaced before any predicted
failure.
39. The TAA is required to ensure that the necessary information is captured by the
FLCs and sent to the DO for analysis, which may result in a re-calculation of
component life.
Health Monitoring
40. Health monitoring may allow prediction when any tolerance or parameter will be
exceeded. Degradation may be unnoticeable by the operator and only become
apparent during maintenance, testing, or via information provided by a third party. In
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Regulatory Article 5722
Guidance
Material
5722(3)
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accordance with RA 4000 series, arrangements must be put in place to allow the
health of the Propulsion System to be monitored throughout its operating life.
Methods of health monitoring may include vibration analysis, performance runs and
wear debris analysis.
SPS/Maintenance Schedule
41. The correct and timely application of preventive maintenance, supported by the
SPS and Maintenance Schedule, underpins PI. The SPS must be periodically
reviewed iaw RA4200 series. Aero engines are often subject to scheduled
maintenance regimes (e.g. component inspections). Any latitude in scheduled
maintenance intervals will be determined through consultation with the DO.
Obsolescence
42. PTs will manage obsolescence in line with JSP886: Def Logs Support Chain
Manual Vol 7 – Supportability Engineering, Part 8.03B – Maintenance Design which
requires an obsolescence management plan as part of the Project TLMP. The PT
may contract out obsolescence management, but the TAA retains overall
responsibility.
Regulation
5722(4)
Validating Propulsion Integrity
5722(4) The TAA shall ensure that the assumptions underpinning PI
are periodically validated.
Acceptable
Means of
Compliance
5722(4)
Validating Propulsion Integrity
43.
The SPS and Maintenance Schedules should be reviewed and updated.
44. The DO should review the validity of design and usage assumptions at a
periodicity determined by the DO, and also in conjunction with any SOIU review.
45. The need for, and potential scope of, sampling in support of validating activities
should be determined and published.
Guidance
Material
5722(4)
Validating Propulsion Integrity
SPS and Maintenance Schedules
46. Due to changeable operational requirements the validity of the Maintenance
Schedule and expected component lives within the design assumptions need to be
verified. In addition, an SPS review will need to be carried out and will include a
review of the ADS and any supporting procedures.
Design and Usage
47. Actual usage data gathered from the as‑flown configuration will be used to
validate or refine the DO’s assumptions. In-use experience of all aircraft systems,
including that of other users, may reveal different failure modes and component lives
than those originally predicted by the DO. Failure rates are generally indicative of the
design assumptions, however where they deviate significantly, consideration will be
given to amending the DO’s assumptions to reflect the revised failure rates. The
impact of any component life or usage changes on critical parts transferred between
operations will need to be clearly understood by PI stakeholders and would be
expected to be reviewed as part of any validation activity. For clarity, the PI strategy
may capture the measures to be taken regarding transfer of critical parts between
operational fleets.
Sampling
48. Sampling is to be actively managed by the PT so that any deviation from the
design specification can be identified and necessary recovery action captured by the
PT. Any sampling requirements are to be published in an appropriate document.
Arrangements are to be made for collating and interpreting sampling results and
sampling targets. Laboratory sample inspections will be carried out on retired
components at specified intervals with a final inspection carried out on components at
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Guidance
Material
5722(4)
Regulatory Article 5722
full life or retirement. Ideally all components need to be inspected at the end of their
lives, but the DO or TAA may decide the quantity of life-expired or retired components
to be inspected. Effects due to environment, maintenance and operating
characteristics that impact upon component integrity can be monitored in order to
enhance the level of safety. Since long periods of time can elapse before cyclic
inspections are due, it is important that all intermediate opportunities to assess
calendar life and wear effects on components are used to the full. All component
inspections during maintenance, repair and overhaul will be logged as this may
preclude the need for component withdrawal for sample inspections.
49. As per Def Stan 00-970 Part 11, the periodic completion of a Technical Life
Review by the DO would be expected as part of any validation activity, in order to
underwrite or revise critical part lives and define any actions necessary for continued
safe operation.
Regulation
5722(5)
Recovering Propulsion Integrity
5722(5) The TAA shall ensure PI is recovered following any loss of,
or potential compromise to PI.
Acceptable Recovering Propulsion Integrity
Means of
50. The following events should be immediately reported to the TAA:
Compliance
a.
Any perceived reduction in the Propulsion System availability or
performance.
5722(5)
b.
Any loss of, or compromise to, PI that is judged to have the potential to
occur on other aircraft within the fleet.
c.
Any change in Propulsion System usage patterns.
51. Arrangements should be made with the DO and, where practicable, external
operators to obtain notification of Propulsion System occurrences with potential readacross.
52. Significant Propulsion System arisings should be reported and evaluated at the
PSIWG.
53. Measures should be taken to recover PI, taking specialist advice from the DO
or independent advisors following any triggering events.
Guidance
Material
5722(5)
Recovering Propulsion Integrity
PI Reporting
54. Type-specific procedures will be published within the ADS detailing the action to
be taken following loss or compromise to PI.
PI Evaluation
55. Where a loss or compromise has been identified/reported an investigation into,
and recovery of, significant damage or failure will be monitored by the PSIWG.
PI Recovery
56. Recovery measures may include repairs, modifications, additional examinations
or testing, changes to component lives, or the imposition of operating restrictions.
Additionally, the results of validation activities and in-service experience may bring
fleet-wide PI into question, which may reinforce any imposed operating restrictions.
Any requirement to impose operating restrictions would need to be agreed with the
relevant Aircraft Operating Authority. Following a loss of PI it may be necessary to
quantify risk and generate recovery options. Component modifications that alter the
performance of the Propulsion System (e.g. increasing shaft speed) may affect other
components in the system and the impact on those components affected will need to
be assessed. Although critical component fatigue lives are usually considered to be
finite, in exceptional circumstances and in order to manage a platform back to ALARP,
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Regulatory Article 5722
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Guidance
Material
5722(5)
the TAA may, in consultation with the DO, authorize critical part life extensions. This
extreme action is to be carefully considered by the TAA if it is to be included as part of
a recovery plan as it can, in itself, trigger a further reduction in confidence in PI.
Regulation
5722(6)
Exploiting Propulsion Integrity
5722(6) The TAA shall ensure PI is exploited to take full advantage
of the aircraft Propulsion System.
Acceptable Exploiting Propulsion Integrity
Means of
57. In-service experience of other platforms or operators should be utilised.
Compliance
5722(6)
Guidance
Material
5722(6)
Exploiting Propulsion Integrity
Utilising in-service experience
58. Data from other platforms or operators whether UK military, overseas military or
civil operators, may be exploited by PTs to further support PI activities, subject to the
following considerations:
a.
The period and nature of operations considered is to be broadly
representative of UK military usage.
b.
The current and expected UK military operating envelope is to be either
benign in comparison with that of other users or the future operating envelope is
to be restricted as necessary.
c.
The effect of any configuration differences between the aircraft and/or
engines being compared.
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