A control bearing beyond limits, an MEL and a ferry permit
You are the AME on duty for a Part 135 operator's float-equipped Cessna 206. During a scheduled inspection you find the left elevator control rod-end bearing has about 1.2 mm of axial play; the manufacturer's limit is 0.5 mm. The bearing is not in stock locally and the earliest delivery is Tuesday. The operator has a charter on Saturday carrying five passengers to a lodge. The maintenance controller suggests three options: (a) enter the item in the MEL as a deferral; (b) issue a maintenance release "subject to inspection before each flight"; or (c) obtain a special flight permit to fly the aircraft empty to the operator's base 180 km away, where the part is in stock. The aircraft is otherwise serviceable and the elevator still moves freely. The operator says the aircraft flew in like this and "it's only a bit of play".
1. Evaluate each of the three proposed options against the rules and the aircraft's airworthiness.
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(a) MEL deferral is not available. An MEL is an approved document listing specific equipment that may be inoperative for a limited period with defined conditions; it is not a mechanism for deferring an airworthiness defect in a primary flight control. Even if the operator's MEL were poorly worded, a control system with play beyond the manufacturer's limit makes the aircraft unairworthy, and no MEL can restore airworthiness.
(b) A maintenance release "subject to inspection before each flight" is not a valid release. A release certifies that the maintenance has been completed and the aircraft is airworthy at that point. Adding a condition that amounts to "we know it is out of limits but will look at it again" is a false certification and would also breach the operator's Part 135 obligations.
(c) A special flight permit is the only route that might allow flight, and only for a specific purpose such as a ferry flight to a repair facility. It requires CAA approval (or approval under the applicable Part 21 provisions), is issued with conditions - typically no passengers, day VFR, specified route, minimum crew, and any inspection or operational restriction needed - and cannot be issued if the aircraft is not safe for that particular flight. With a control bearing at more than twice the limit, the CAA may well refuse; the realistic options are repair on site or transport the part to the aircraft.
2. If the aircraft is not released, what must be recorded and communicated, and how do you handle the operator's pressure?
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Record the defect and the measurement in the aircraft's maintenance records, state the limit and the approved data used, and record that no maintenance release was issued. The aircraft should be placarded or otherwise controlled so it cannot be dispatched inadvertently, and the operator's continuing airworthiness/technical records should show it as unserviceable. If the operator holds a Part 135 air operator certificate, its maintenance controller and senior person need the information in writing so the scheduling system reflects reality.
On pressure: the "it flew in like this" argument is irrelevant - continued operation does not make an out-of-limits component airworthy and may indicate the operator has been flying an unairworthy aircraft, which is itself a matter to record and consider reporting. Be clear that you will not certify, explain the specific limit and consequence, and offer the legitimate alternatives (expedite the part, source it from another operator, repair locally, or apply for a special flight permit). Keep contemporaneous notes of instructions to release and your responses. If the operator dispatches the aircraft anyway, that is a serious matter for the CAA.
3. The controller says the bearing play was already noted two inspections ago but "signed out as serviceable". What does that change?
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It changes the scope of the problem. If an earlier inspection recorded the play and certified the aircraft as serviceable, that earlier certification may have been incorrect, and the aircraft may have been operated outside its limits since then. You should locate the earlier entries, check what was measured and against which limit, and record the history accurately. Do not amend or "tidy" the earlier entry.
The matter should go to the organisation's quality manager and, depending on the facts, may need to be reported to the CAA as an airworthiness concern and reviewed under the operator's occurrence reporting arrangements. For your own decision, the earlier sign-off has no bearing on today's measurement: the aircraft is out of limits now. If anything, the history supports escalation rather than release, because a pattern of signing out known defects suggests the maintenance control system is not detecting unairworthy conditions.