Originally Posted by
fumje
For reference, a Formula 1 car accelerates at about 2g. That is far more extreme than most people are accustomed to experiencing anywhere.
I agree that there is likely a data fidelity issue here, and the headline-grabbing numbers of 8600fpm drop / strangely-symmetric 8600fpm, 2.7g climb are spurious extrapolations from noisy data. Can a 777 physically do any of that?
It's not that nothing happened — it's that what did happen likely isn't as dramatic as the report is suggesting.
Could you share what they are saying or point to where it is? I am genuinely curious to know more information.
Originally Posted by
jmastron
I'm not sure it says that, if the data showing how low it got is correct. Unless you're thinking the plane nearly stalled, and the nose was pushed down to recover and gain airspeed, which luckily they did with *just* enough altitude left? In context, 800 feet is ~4 777 lengths.
If only there was a way to capture the aircraft's telemetry, control positions, cockpit reactions and conversations... Not only was the CVR overwritten by flying to SFO, but I assume no FDR data was captured before it was overwritten either? I still think that in a case like this, or the AA plane that crossed the runway in front of the Delta plane taking off, or the AC flight that almost landed on the occupied SFO taxiway, that it would be ideal if the data were ensured saved as a matter of practice, yes, even if that means canceling this or the next flight.
In this case, it sounds like the pilots were forthcoming to United at least, and are getting appropriate retraining, but the rest of the industry and passengers have a vested interest in understanding what went wrong and how to ensure it doesn't happen again.
from
https://data.ntsb.gov/Docket/Documen...%20UAL-Rel.pdf
and
https://data.ntsb.gov/Docket/Documen...phical-Rel.pdf
The entire incident occurred in ~ 15 seconds, ~1425 ft of altitude lost. vertical rates recorded from -1216 to -8576 for the incident period.
https://data.ntsb.gov/carol-repgen/a...ort/106734/pdf
The first officer stated that he “knew the captain was having difficulty with airspeed control”,
and he queried the captain about it as he considered if his own (right side) instrumentation
may have been in error. He did not receive an immediate response from the captain. Both
pilots recalled that, about this time, the airplane’s pitch attitude was decreasing, and the
airspeed was increasing. The first officer recalled that that the captain asked for flaps 1 soon
after he had called for flaps 5, and when the first officer set the flaps to 1°, he then noticed the
airspeed had increased further, and the control column moved forward.
Both pilots recalled hearing the initial warnings from the ground proximity warning system
(GPWS), and the first officer recalled announcing “pull up pull up” along with those initial GPWS
warnings. The captain then pulled aft on the control column, initially reduced power to reduce
airspeed, and then applied full power to “begin the full CFIT [controlled flight into terrain]
recovery.” The first officer recalled that, as the captain was performing the recovery, the GPWS
alerted again as the descent began to reverse trend; data showed this occurred about 748 ft
above the water. After noting a positive rate of climb, the captain lowered the nose to resume
a normal profile, ensured that the flaps and speed brakes were fully retracted, and engaged the
autopilot. The remainder of the flight was uneventful.
IOW, crew had to recover aircraft from flying into the ocean due to their own error.
https://data.ntsb.gov/Docket/Documen...20Data-Rel.csv
