On a cloudless morning in April of this year, a C-5B transport of the 436th Airlift Wing took off from Dover AFB in Delaware, bound for Ramstein Air Base in Germany on a routine supply mission. The C-5 is the United States Air Force's largest transport; this one's takeoff weight was 742,000 pounds, including a quarter-million pounds of fuel. Aboard were 17 people; the crew included three pilots and three flight engineers, collectively representing more than 26,000 hours and 92 years of C-5 flight experience.
Shortly after takeoff the crew observed an intermittent warning light for an unlocked thrust reverser on the number two engine, the inboard engine on the left side of the aircraft. An unlocked reverser is a potential hazard-there is a chance of unexpected deployment in flight-and so after due deliberation and cross-checks the crew secured the engine and turned back to Dover. They did not declare an emergency, but did request an expedited approach. They anticipated a routine landing, though at a higher than usual weight; they had, after all, three good engines and a perfectly functional aircraft. A few minutes later, the C-5 lay, a mangled wreck, a third of a mile short of the Dover runway. Thankfully fire did not break out and all aboard survived, although some were seriously injured. Newspaper reports the next day hailed the fatality-free crash as a miracle.
Two months later the Air Force released the report of its investigation of the accident. It turned out to have been a miracle, all right-a miracle of crew interaction gone awry. So bizarre and striking was the story that the investigation uncovered, that an internal Air Force video simulation, accompanied by cockpit voice recorder dialogue and animated indications of relevant instruments, was soon making its way around the internet. I, for one, received it from three different people.
In order to allow the right seat pilot, a C-5 instructor with five years and 2,330 hours in type, to log the sortie, the left seat pilot, who had flown the takeoff, had turned control of the aircraft over to him. Investigators identified as causal to the accident three procedural errors, all of which involved, in one way or another, the right seat pilot.
After deciding to return to Dover, the crew had informed the controller of their intentions and had elected to cancel IFR and make a visual approach. They chose Runway 32, although the 6-knot surface wind was from the south, because it was the longest runway. Presumably they wanted plenty of room to let the heavily loaded airplane roll out with moderate braking. Runway 32 did not have a precision instrument approach, but it did have a PAPI, or visual glideslope. It was a perfectly clear day, and there was no reason to anticipate any difficulty with a visual approach. The approach began, however, hundreds of feet below the PAPI glideslope and never intercepted it.
The flight received landing clearance six miles from the runway, about 1,200 feet above the ground and about 15 knots above the bug speed of 166. Flaps were at 40 percent-the recommended setting for an engine-out approach. Shortly after, however, the pilot called for "landing flap," and the flaps came down to 100 percent. Full flaps lowered the bug speed to 146 knots and would shorten the landing roll, but also increased the drag that the three remaining engines would have to overcome. Ideally, full flaps, if used at all on an engine-out approach, would be reserved until landing was assured, not when the airplane was still miles away from the runway and, incidentally, at an unusually low altitude. Nevertheless, the C-5 was perfectly capable of landing from this position and with this flap setting, on three engines, and neither the left seat pilot nor the third pilot, who was sitting in the jumpseat behind the other two, commented on the early selection of full flaps.