FedEx Burns Another

Air Safety Week, August 7, 2006

Safety Lessons from the Latest Accident of a FedEx Aircraft

It's been an article of faith among multi-engine pilots that if you drive your bird in a little hard, forget to flare or kick off the drift, then all that will happen is that touchdown will feel significantly different, a few fuel-tank seams might weep tears of fuel, and the engineers might rib you for causing them extra work.

Of course, you will have admitted your sins to them, written up the bird and waited anxiously while they carry out a heavy landing inspection. That check will progressively indicate, item by item, whether you've permanently bent anything, or whether they need to check more deeply because of what they've found. Most of the time, you will not have bent anything and the procedure is quite perfunctory. It could happen that you've bottomed out the oleos and witness-marked an indicator. Rarely will a heavy landing blow or even scrub a tire, let alone damage the gear or airframe.

After the latest FedEx MD-10 burning on runway 18R at Memphis, Tennessee on July 30, the company's pilots might be forgiven for surrendering up the above article of faith. In fact, they may be pondering why their "Mad Dogs" are so lame that their legs collapse at will. FedEx pilots are made of sterner stuff, so they will just take it on the chin and polish their landing techniques, making sure to properly adrenalize before each and every landing. "Failure is not an option" I seem to recall someone famous saying, while baying at the moon. Evidently the Mad Dogs 10 and 11 never got that message. They appear to be particularly weak-kneed.

It Seldom Happens

In the latest accident, the left landing gear failed on the airplane during landing, sending sparks into dry grass beside the runway that ignited a fire. Three people on board used an emergency landing chute on the right side of the plane to safely escape, avoiding the burning engine on the other side. Fire crews responded quickly and doused the fire with foam, containing it to the engine area and preventing it from spreading to the rest of the aircraft. The plane, identified as FedEx Flight 630, had departed from Seattle, Washington. Les Dorr, an FAA official in Washington D.C., said landing gear failure is a rare occurrence. "A landing gear collapse on a large transport-type aircraft is a pretty rare event," Dorr said. "It seldom happens."

The MD-10 was a valiant attempt by FedEx/MD (and then MD's takeover merchant Boeing) to use up the remaining life in the plentiful old DC-10 airframes by upgrading the cockpit to an MD-11 style two-man standard, simultaneously rewiring and freighter-converting it. Like the two-man MD-11F operation, it promised to be a very economical long-haul freighter. The DC-10-10 had a Max Gross Weight increase to 446,000lbs and the DC-10-30 to a massive 580,000lbs in the Series 30 MD-10. That boost in cargo-carrying capability required "structural changes".

The Advanced Common Flight Deck was intended to allow FedEx pilots to operate either the MD-10 or MD-11 interchangeably, for maximum scheduling efficiencies. However, when the FedEx pilots got their hands on the MD-10, they protested vociferously. They considered that there were sufficient dissimilarities as to make any dual qualification unsafe. Unlike the 757/767 and the A340/A330 combos, the MD-10/MD-11 basic designs and handling qualities were of two entirely different eras. The company didn't agree and the FAA and Boeing backed FedEx, so the pilots got to operate both. One wonders whether the Flight Operations Quality Assurance (FOQA) program has since disclosed any lingering safety interludes for those who fly both, interchangeably. FOQA regularly checks data-recorders for any pilot handling quirks that would be better if they were ironed out with counseling or added training. One could also speculate as to whether any such handling difficulties, particularly the touchdown, might have carried over into longer term aircraft fatigue damage. The MD-11 has had to undergo a number of flight-control software patches in an attempt to cure it of some of its near-the-ground vices. It is reportedly very unforgiving of a one gear first hard touchdown, as the pilot of a Mandarin Airlines passenger flight found on his arrival in Hong Kong on the night of Aug. 22, 1999.

Turning Turtle

That aircraft lost its right gear and wing, inverted and caught fire, killing 3 passengers.

The pilot had disconnected the autopilot but left the autothrottle engaged, which failed to compensate for the gusting crosswind. An amateur video showed the aircraft's quite normal approach in turbulent conditions, followed by a high-rate descent beginning at around 50 ft RA (radar altimeter). Wind-shear had caused a sudden loss of around 20kts and the autothrottle failed to respond. That was the height it was software-scheduled to throttle-close for the flare (or landing round-out).

Near to max landing weight, and in an unremarkable less than 4 degree right wing down attitude (for the crosswind), the aircraft hit with a high rate of descent. This allowed the RH oleo to bottom out, the #3 engine to touch the runway and break off, taking the RH wing with it. Looking at the relative positions of the wing-gear and the engines (further outboard), it's not surprising that the weight of the engine should allow its downward inertia to lever the wing off above the gear in a hard touchdown.