MEL Deferral and Airworthiness Directive Conflict on a B727 Freighter
During a preflight inspection at Lagos, the Flight Engineer of a Nigerian-registered Boeing 727-200F finds the maintenance release endorsed with MEL item 29-3-1: hydraulic system B electric pump inoperative, deferred for a maximum of 10 flight hours. The aircraft has flown 9.5 hours since the deferral. The tech log also shows that Airworthiness Directive AD 2019-14-07, requiring an inspection of the hydraulic pump wiring at 50-flight-hour intervals, was last complied with 52 flight hours ago. The planned sector is 2.2 hours to Accra with a 45-minute alternate. The operator's maintenance control says the AD 'does not apply because the pump is already deferred' and asks the FE to sign the acceptance. The FE notices the maintenance release is signed by a mechanic but not by a certifying engineer.
1. Is the aircraft legally dispatchable on this sector? Assess each defect and certification issue separately.
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No. There are at least three independent bars to dispatch.
- AD overdue: An Airworthiness Directive is mandatory. The inspection was due at 50 flight hours and is now 2 hours overdue. The aircraft is not in compliance with its airworthiness requirements. An MEL deferral of the affected pump does not suspend or waive the AD; maintenance control's statement is wrong.
- MEL limit: The MEL allows a maximum of 10 flight hours. The aircraft has already used 9.5 hours. Only 0.5 flight hours remain, while the planned sector is 2.2 hours plus a 45-minute alternate. Even if the AD were not an issue, the deferral would expire in flight.
- Maintenance release: A maintenance release signed by a mechanic but not by a certifying engineer is not a valid certification of airworthiness for the flight. The FE cannot cure this by accepting it.
The correct conclusion is that the aircraft must not depart until the AD is complied with, the MEL status is resolved or closed, and a valid maintenance release is issued by an appropriately authorised person.
2. What records and maintenance actions must be completed before a lawful release, and what is the Flight Engineer's role in that process?
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The approved maintenance organisation must:
- Accomplish AD 2019-14-07 and record the compliance entry with the AD number, method, date and flight-hour/cycle reference.
- Inspect the deferred hydraulic system B electric pump and wiring as required, and rectify any defect found.
- Close or re-issue the MEL deferral only if the item is still eligible and the limit has not expired; a new deferral cannot be used to avoid the AD.
- Issue a new maintenance release signed by a certifying engineer with the correct approval.
- Update the tech log, aircraft logbook and AD compliance record so the next crew and inspector can trace the status.
The FE's role is to verify that the release and tech log support the flight, not to certify maintenance. The FE should refuse to sign acceptance, inform the commander, and record the discrepancy through the operator's maintenance and safety reporting system.
3. The commander says the flight must go because the cargo is perishable and the operator's maintenance control has 'accepted responsibility'. How should the FE respond?
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The FE should treat the commander's commercial pressure and maintenance control's verbal assurance as irrelevant to the airworthiness decision. Responsibility for an illegal release cannot be transferred by a telephone statement.
The FE should:
- State the specific technical bars: AD overdue, MEL limit insufficient, and invalid maintenance release.
- Ask for written confirmation from a certifying engineer that the AD has been complied with and a valid release issued. If that cannot be produced, the answer is no.
- Inform the commander that dispatch would breach the Nig. CARs and the operator's approved maintenance control procedures.
- Document the refusal in the tech log or a separate occurrence report and notify the safety office.
If the aircraft is nevertheless dispatched, the FE should not sign as having accepted it, and should report the matter to the NCAA. A refusal based on airworthiness grounds is protected; concealment or signing under pressure is not.