Technical Records – Component Overun

In its February 2015 General Aviation Mandatory Occurrence Report (MOR) Listing, the UK Civil Aviation Authority (UK CAA) summarises an MOR from a twin turboprop operator’s Continuing Airworthiness Management Organisation (CAMO).  This MOR is a neat case study on technical record errors and how one CAMO now tries to prevent them.

On preparing to send the log card to stores for NLG Retraction Jack, the engineer noticed that the last overhaul date on the log card was 24/9/08, more than 6 years ago. The overhaul EASA Form One is dated 25/9/08, verifying the log card. The part has a 12000 cycle/6 year overhaul life, meaning the next overhaul was due in September 2014. The Retraction Jack was removed from the aircraft in February 2015, and the overhaul therefore went overdue by approximately 5 months.


The ’cause’ would appear to be the overhaul of the retraction jack being incorrectly claimed on the maintenance database from the date of first fit, 1st April 2009, rather than the date of overhaul. This would have led planning to work on the assumption that the overhaul was due by 31st March 2015, as forecast.


Since 2012 [a] procedure, has been introduced for all critical components to be checked by a second member of the tech records department post fitment. This procedure should discover any errors like that made in this case, in time to rectify them before a maintenance activity is due. Therefore this is unlikely to reoccur for any critical components fitted since the procedure was introduced.

It is also noticeable that this organisation had anticipated this type of error and had proactively changed its procedures already.  Aerossurance has previously written about Professor James Reason’s 12 Principles of Error Management.

Aerossurance is pleased to sponsor this Royal Aeronautical Society (RAeS) Human Factors Group: Engineering conference on 12 May 2015 at Cranfield University: Human Factors in Engineering – the Next Generation

For support on preventing maintenance errors, continuing airworthiness management and safety assurance, contact aviation consultancy Aerossurance: