An MEL deferral that does not cover this flight
You are the single pilot of a Cessna 402C due to depart Port Moresby (AYPY) at 06:10 on an IFR passenger charter to Madang (AYMD) and back, eight passengers on each sector. During the pre-flight instrument check the pilot's attitude indicator (No.1 AI) stays off-flag; the co-pilot's AI is serviceable. You hold an instrument rating and are current.
The operator's approved MEL item 34-11-01 permits the No.1 AI to be inoperative 'for day VFR flight only, provided the No.2 AI is serviceable and the aircraft is not operated in IMC'; the item must be placarded and recorded on the maintenance release. The chief engineer is away; the line engineer says he will 'do the MEL' and writes the defect in the technical log, but not on the maintenance release.
Weather: AYPY SCT020 BKN040, 8 km in showers; AYMD fine. The route is over high terrain and cloud is forecast for most of the morning.
1. Can the flight go as planned? Identify every reason.
Read the worked answer
No. The MEL is relief from the airworthiness requirements, granted within stated limits - it is not a list of things that may be ignored.
- Item 34-11-01 permits the No.1 AI to be inoperative only for day VFR, with the No.2 AI serviceable and no flight in IMC. Your charter is IFR, over high terrain, with cloud forecast - IMC is likely and the clearance will be IFR. The conditions of the deferral are not met.
- The defect is not recorded on the maintenance release. Until the deferral is certified by an authorised person and entered, the aircraft has not been released with the defect deferred, and you cannot treat it as airworthy for the flight.
- The pilot in command is responsible for establishing airworthiness before flight, including checking the release and the MEL. 'The engineer said it was fine' is not a defence for you.
Options: repair the AI or fit a serviceable unit (the cleanest), or operate day VFR only if the whole flight can be conducted in VMC within both the MEL and the exposition. With eight passengers and cloud over high terrain, day VFR is not a realistic option today.
2. Suppose the MEL had no entry for the attitude indicator at all. Would that make it easier to dispatch?
Read the worked answer
No - the opposite. If the MEL does not list an item, there is no relief for it, and every item required by the type design, the flight manual and the operating rules must be serviceable.
- An MEL is an approved document allowing specific equipment to be inoperative under defined conditions. It is not an exhaustive list of what the aircraft needs; it is a list of exceptions to the normal rule that everything works.
- The attitude indicator is required equipment for IFR flight under the operating rules and the aircraft's equipment list. Without MEL relief, an inoperative AI grounds the aircraft for IFR.
- Some MELs carry a 'no relief' note for particular items. Read the item; if it is not there, ask the approving authority rather than assuming.
The practical test: can you point to a specific MEL item that authorises this defect in these conditions, certified on the maintenance release? If not, the aircraft is not airworthy for the flight.
3. The operator proposes to ferry the aircraft to Moresby for repair. What is required, and what is not permitted?
Read the worked answer
A ferry or positioning flight is a different operation requiring a different approval.
- A special flight permit (or equivalent ferry authorisation) must be issued by the authority, or by an organisation approved to do so, with conditions attached - typically no passengers, day VMC, a specified route and altitude, and sometimes a specified crew.
- It cannot be used to carry revenue passengers, so it does not solve this charter. The passengers must be re-accommodated or carried on another serviceable aircraft.
- The permit conditions are the limits of the flight. If the weather does not allow day VMC, the ferry waits - the permit is not a licence to press on.
- If a spare AI can be fitted at Moresby, doing that before the charter may be cheaper than a return ferry plus the cancelled flights.
Before any flight, make sure the maintenance release and technical log entries correctly record the aircraft's status. Sloppy paperwork on a deferred defect is how an airworthy aircraft becomes an unairworthy one in the eyes of the regulator.