Recommendation Date
Recipient Name
ATD MoT
Text
Institute a requirement in the Certificate of Airworthiness inspection of refurbished aircraft that all flight instruments shall have been overhauled or are within their approved "shelf" life if the aircraft has not been operated for a significant period before the refurbishing was completed.
Reply Text
NZCAR Section F9 - Maintenance of Group 1 Instruments - specifies they may be maintained 'On Condition'. Instruments identified by the designator 'GenINST' shall be tested at 2 yearly intervals when installed in IFR aircraft. 'GyroINST' instruments shall be removed from the aircraft and tested or repaired as necessary also every two years for IFR Air Transport aircraft, or 'whenever a defect is suspected or observed'. In addition, Group 1 Instruments held in store shall be subject to tests at periods recommended by the manufacturer or at periods not exceeding 2 years from the date of manufacturer or last overhaul. (Except instruments which have been inhibited and stored in hermetically sealed containers need not be re-tested). The Fieldair Freight Maintenance Programme for the CV580 required an avionics inspection to be carried out at every periodic inspection, which occurred ever 100 flying hours.
Thus the recommendation is effectively already embodied in the Regulations which require regular tests for both stored instruments and those fitted on aircraft. The recommendation does not appear to have any foundation or relevance to the accident since it is acknowledged the ADI defect was known by the company and had been entered in the maintenance log 'Deferred for parts'.
In the rewrite of the New Zealand rules, presently under way based on the FARs, it is intended to abolish the fixed removal and check periods currently in NZCAR Section F9 and replace them with 'On Condition' maintenance for all aircraft in conjunction with compliance with manufacturers recommendations. It has been found in practice this is a more cost effective system since removing a fully functioning instrument can often create problems, rather than lessening them.
Thus the recommendation is effectively already embodied in the Regulations which require regular tests for both stored instruments and those fitted on aircraft. The recommendation does not appear to have any foundation or relevance to the accident since it is acknowledged the ADI defect was known by the company and had been entered in the maintenance log 'Deferred for parts'.
In the rewrite of the New Zealand rules, presently under way based on the FARs, it is intended to abolish the fixed removal and check periods currently in NZCAR Section F9 and replace them with 'On Condition' maintenance for all aircraft in conjunction with compliance with manufacturers recommendations. It has been found in practice this is a more cost effective system since removing a fully functioning instrument can often create problems, rather than lessening them.
Related Investigation(s)