Engine Change With Calibration and Rigging Gaps
You are the maintenance controller for a PNG charter operator. An engine was removed and replaced after a compressor failure. The new engine came with a serviceable tag and a traceable logbook. The installation was certified by a licensed engineer; however, you notice the torque wrench used for the engine mount bolts had a calibration sticker expired 3 months earlier. The engine control rigging was checked and signed, but the rigging pin was not listed in the tooling record. The aircraft maintenance release has been signed and the aircraft is scheduled for a passenger flight in two hours. The engineer says the bolts were torqued to the manual value and 'felt right'. The operator asks you to release the aircraft. The aircraft is a single-engine turboprop operating under PNG CASA rules, and the maintenance organisation holds an AMO approval.
1. Identify the airworthiness and documentation defects in this engine installation. Explain why 'felt right' and the signed release are not sufficient evidence.
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The expired torque wrench means the mount-bolt torque has no valid calibration traceability. 'Felt right' is not acceptable evidence; torque is a controlled measurement, and an out-of-calibration wrench may read high or low. The missing rigging-pin entry breaks the tooling and rigging record and makes it impossible to show the control rigging was set with the correct pin and procedure. Both are airworthiness defects, not paperwork trivia, because they affect the evidence that the installation meets the manual.
A signed maintenance release does not cure missing evidence; it confirms the signatory believed the work was done correctly. You also need to confirm whether the task requires a duplicate inspection and whether the engine change requires an operational check or other specific inspections.
2. Decide whether to release the aircraft for the passenger flight. Set out the corrective actions and records required.
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Do not sign the release or allow the passenger flight. Have the mount bolts re-torqued with a calibrated wrench, or verified by an approved method, and have the rigging checked with the correct pin recorded. Complete the missing entries, including tooling calibration and rigging-pin identification. If a duplicate inspection is required, arrange it.
Only after the corrected work and records are complete should the maintenance release be issued. Inform the operator of the delay and the reason. If the aircraft has already flown, raise a defect and review the need for a report under the organisation's procedures.