Industry Viewpoint: Maintenance Turnovers

March 11, 2010
If you know something, say something

Pilots have it drilled into them that crew changes require detailed briefings and de-briefings, pilots to pilots and pilots to maintenance. What they know and don’t pass on can hurt or kill someone. Flight departments are so sensitive to the importance of proper briefings and debriefings that they specifically train their crews in how to do this correctly. Some CRM programs even include training on pilot to mechanic debriefings.

Debriefings and debriefings
What amazes me is that a similar program does not exist to train mechanics on briefings and debriefings to other mechanics during shift changes or turnover of work. The results can be tragic.

As an A&P mechanic and NTSB board member, I investigated a number of accidents that involved maintenance errors that could have been prevented by proper debriefings. The most famous example is the May 11, 1996, ValuJet accident in the Florida Everglades.

As many of you probably recall, a fire in the forward cargo compartment brought the aircraft down. The fire was started by oxygen generators that were improperly prepared for shipment by maintenance. Specifically, the protective caps were not installed over the triggering device as required by the maintenance manual. Normal aircraft loading or cargo shifts during flight caused the oxygen canisters to ignite and the fire spread throughout the cargo compartment and eventually the entire aircraft.

A chain of causal links
While every accident, including this one, is comprised of a chain of causal links, one of the causal links in this particular accident was mechanic to mechanic communication during shift change or turnover of work.

The NTSB investigation uncovered that the canisters being shipped on the aircraft that crashed had been removed from another aircraft whose passenger oxygen system was in for maintenance. The investigation further uncovered that in the 30 days that the oxygen system was worked on, not a single piece of required work-in-progress (turnover) paperwork was completed. This requirement is so important that it is embedded in most repair station and air carrier maintenance manuals.

This means that every time a mechanic worked on the oxygen system, he or she should have recorded the work accomplished and the work that still needed to be done. In this case, the paperwork should have clearly indicated that the protective caps needed to be installed. It did not. This resulted in the oxygen generators being boxed and placed on the ValuJet MD-80 aircraft on that fateful May day in 1996.

The onsite investigation and recovery effort took months. The plummeting aircraft had shattered and burned in one of the most desolate locations in Florida. Human remains were few. I saw the aftermath of the wreckage and met with the devastated family members of the victims.

It was particularly painful for me, as a mechanic, to ultimately learn that one of the causal links in the accident chain could have been broken by a mechanic properly following required manual procedures on turnover, thus averting disaster.

While the manual requirements may have been clear, training on those requirements was not. In my 40 plus years as a mechanic and my nine years as an NTSB board member, I have never seen a mechanic training program that includes training in proper turnover procedures. It’s time they did. Just as flight departments have invested heavily in proper crew change procedures, maintenance departments need to do the same.