Audit Finds an Expired Calibration on the Pitot-Static Test Set
During a routine records audit, an AME finds that a 24-month altimeter/static system test and transponder check on a Cessna 208B were signed off four months ago. The entry references a specific ramp test set and a calibration due date. The calibration certificate on file shows the test set's calibration expired two weeks before the test was performed. The aircraft has since flown 180 hours on 60 sectors, including IFR departures from an international airport. The previous AME who signed the entry has left the company. The operator's quality manager asks the current AME to 'correct the paperwork' by re-issuing the entry with a different test set serial number and current date, so the aircraft can continue its next charter. The aircraft's static system has not shown any discrepancy, and the transponder replies normally on the ground.
1. What is the airworthiness status of the aircraft, and what immediate action should be taken?
Read the worked answer
The original test cannot be accepted as valid because the test equipment was out of calibration. The aircraft's altimeter/static system and transponder performance were therefore not demonstrated at the required interval, even though no discrepancy has been reported. The aircraft should not be released for IFR flight until the required tests are repeated with calibrated equipment and the results are satisfactory.
Immediate actions include quarantining the out-of-calibration test set, notifying the quality manager and the operator, and scheduling the repeat tests before the next flight. If the aircraft is already in service, assess the affected flights and whether any reportable occurrence or airworthiness concern exists. The fact that the aircraft has flown 180 hours without a reported problem does not validate the original test; it only affects the urgency and scope of the investigation.
A maintenance release must reflect the aircraft's actual condition. Do not certify the aircraft as airworthy based on an invalid test.
2. What records correction is appropriate, and what would be improper?
Read the worked answer
The improper action is to re-issue the original entry with a different test-set serial number and a current date. That would falsify the maintenance record and conceal the fact that the test was performed with uncalibrated equipment. The original entry should remain in the record, because it documents what actually happened.
The appropriate correction is a new entry that explains the finding, identifies the invalid test, and records the repeat test performed with a calibrated test set. Reference the new calibration certificate, the test procedure, and the results. If the original entry is annotated, use a correction method that preserves the original text and identifies the person making the correction. Do not erase, overwrite, or backdate.
Also update the calibration log and the audit finding, and record any corrective action taken to prevent recurrence, such as a calibration-status check before test equipment is used.
3. Who should be notified, and what must be done before the aircraft is returned to service?
Read the worked answer
Notify the quality manager, the operator's continuing airworthiness management function, and, where required by the regulations or the operator's procedures, the competent authority. The finding may also need to be assessed under the operator's occurrence-reporting system because an aircraft may have been operated without valid altimetry/transponder tests.
Before return to service, repeat the altimeter/static system test and transponder check with calibrated equipment, complete any corrective maintenance found during the tests, and make a new certification entry. Verify that the test equipment calibration is current and traceable. Review the aircraft's maintenance program to confirm the next due date is correctly established from the repeat test.
The certifying AME must be satisfied that the aircraft meets the applicable airworthiness requirements and must sign within the scope of the licence. The records should show the full sequence: finding, invalidation, repeat test, result, and release.