I referred yesterday to the American Airlines runway excursion at Jackson Hole, Wyoming. That's looks like a tough, could-happen-to-anyone situation. The high airport elevation makes your gut instincts wrong, because as a result of low density air the airplane is moving faster over the ground than the airspeed indicator shows. The visibility means that you're on the gauges until decision height, then, drifting in a crosswind, you look up, find the runways lights off to one side, and land on the pavement that you trust is outlined by the lights, with everything reflecting off the swirling snow. The snow doesn't even look like snow. It looks like some weird flashing thing, just stabbing at you. Honestly, passengers who are perfectly familiar with the terrestrial sort of snow ask "what is that?" But you can't sit there and stare mesmerized like the Enterprise bridge crew. You have to land, make sure the thrust reversers have deployed, brake, trust the antilock, keep straight with no visual references and uncertain braking conditions and by that point all the formulae and calculations and runway friction data are academic. You are doing your job and just hoping that the rate of deceleration you're getting is such that by the time vee equals zero, half eh tee squared is less than runway length minus touchdown point. The Boeing 757 is slowed after landing by thrust reversers which direct the engine thrust forward, spoilers, which both provide aerodynamic drag and reduce the lifting power of the wings, increasing the weight on the wheels so that the wheel brakes are more effective.
The chart I have for the Jackson Hole runway 19 ILS approach shows a standard 200' decision height and what Canadians call an advisory visibility of three quarters of a mile. That is, one can reasonably expect to be able to see to land on the runway with that visibility and a ceiling above 200'. Reported conditions at the airport were a ceiling of 400 feet, light snow and visibility of 1 mile. Winds were 10 knots from 240 degrees. So the pilots expected to be able to land, and they did, but what went wrong?
I don't know. It's a sexy looking airplane, but I've never flown anything remotely like it. The information I have tells me:
The FDR data indicate that the aircraft touched down at approximately 132 knots. At touchdown, the air/ground parameter changes to "ground" for approximately one second and then switches to "air" for approximately ½ second before changing back to "ground" for the remainder of the recording. The thrust reverser discrete parameters on the FDR indicate that approximately 18 seconds elapsed from the time the reversers began moving until they were fully deployed.
I don't know the recommended touchdown speed for the aircraft at its actual landing weight, but 132 knots does not seem out of line. Without more knowledge of this aircraft systems I naïvely assume the air/ground parameter information means that the aircraft bounced slightly. This appears to have reset the thrust reversers and spoilers the same way a go-around would. Both are armed on approach and then activate automatically when the airplane sensors show that the main wheels are on the ground. This discussion suggests that wheel braking is restricted to half until sensors report that there is weight on the nosewheel. More informed discussion elsewhere doesn't mention the possibility of a bounce, and it's hard to see in the video. It does show very slow deployment of reverse thrust. Perhaps it was a landing gear sensor that "bounced" rather than the physical airplane. There also seems to have been a maintenance problem with the autospeedbrake (i.e. spoiler) handle in the cockpit, something that I'm sure will be scrutinized closely.
Look in the comments for possible contributions from readers more knowledgeable about this aircraft.