Engineers Installed Actuator Upside-Down on VS43
Jeff Edwards October 22, 2015
A report on a Virgin Atlantic flight that was forced to land with jammed landing gear, attributed the incident to an actuator that had been installed upside down by maintenance workers.
The Air Accidents Investigation Branch (AAIB) determined that an improperly installed actuator was responsible for a gear jam that forced Virgin Atlantic Flight 43 to land without part of its main landing gear working on December 29, 2014. Investigators blame both the loss of hydraulic pressure that caused the Gatwick Airport (LGW) to McCarran International Airport (LAS) flight to turn around after takeoff and the main gear jam that forced the plane to land without one of its main gear bogies working.
Virgin Atlantic previously published an internal report attributing the malfunction to maintenance workers incorrectly installing a new actuator in the Boeing 747-400. The Virgin Atlantic document reportedly made 28 separate recommendations to prevent similar mistakes from occurring.
The recently released AAIB Field Investigation report, however, indicates that the mistake was owed as much to the procedures in place as it was to human error. The report notes that the repair work involved was so physically exhausting that mechanics may not have had the strength to concentrate on the fine details of their work as well.
“The task became so physically demanding that the maintenance team became entirely focused on just attaching the actuator to the aircraft, in order to relieve themselves of the [weight],” the AAIB report explains. “As such, they had no remaining capacity to ensure they installed the actuator in the correct orientation.”
The report also points out that the part itself was “virtually uniform in shape and color, with no obvious indicators regarding orientation.” The AAIB also found that labels on the parts and the aircraft were “inherently open to misinterpretation” — a factor which led to the upside down installation of a critical piece of equipment on the jumbo jet.
While I certainly blame the maintenance crew on this one... why wasn't the part designed so that it only goes in one way? Or is this one of those things that any idiot should have known better? Either way, scary stuff. I propose said engineer be forced to fly on any aircraft he replaces parts on for the next 6 months. That'll fix that little problem.
I seem to recall that in the book "Stranger to the Ground" by Richard Bach there is a story about a old-timer mechanic who routinely installed F-84F aileron bolts with the heads on top and the nuts threading on from underneath, despite the fact that the installation manual specified that they should be the other way around. This was only discovered after a number of fatal crashes caused by locking controls. The mechanic was offered early retirement without being burdened with the knowledge that his mistake had cost lives.
I estimate that 1 in 30 seat belt straps are installed upside down on flights that go for maintenance..