UA2477 suffers runway excursion at KIAH
Drifting to the MAX…
“With about 1,000 ft and 500 ft of runway remaining the airplane ground speeds were about 72 kts and 57 kts respectively. The right turn to exit the runway was initiated at about 39 kts groundspeed and the aircraft departed the end of the paved surface at about 22 kts.”
NTSB Aviation Investigation Preliminary Report - N27290, UAL2477
“With about 1,000 ft and 500 ft of runway remaining the airplane ground speeds were about 72 kts and 57 kts respectively. The right turn to exit the runway was initiated at about 39 kts groundspeed and the aircraft departed the end of the paved surface at about 22 kts.”
NTSB Aviation Investigation Preliminary Report - N27290, UAL2477
I wonder how the ground speed is determined. If it is from the tires then as the slide begins the ground speed will only be in alignment with the fuselage and not represent the true velocity of the aircraft. By way of example - if the plane is sliding directly sideways the tires will not rotate regardless of the slide speed.
I wonder how the ground speed is determined. If it is from the tires then as the slide begins the ground speed will only be in alignment with the fuselage and not represent the true velocity of the aircraft. By way of example - if the plane is sliding directly sideways the tires will not rotate regardless of the slide speed.
I see - there is a ground speed graph that appears to be from the DFDR as well as the ADS-B data.
Comparing the two would allow finding out when the slide started, but the graph is too compressed to make that easy.
Comparing the two would allow finding out when the slide started, but the graph is too compressed to make that easy.
It seems that it was not so much UA2477 that suffered a runway excursion, but it was more the runway and grass borders which suffered this excursion upon them.
Autobrake 1 and stowing the speedbrakes (and thus cancelling autobrake) early into the landing roll, combined with idle reverse on a contaminated runway...
What were they thinking will stop them, aerodynamic drag?
What were they thinking will stop them, aerodynamic drag?
Ditto re stowing speedbrakes and idle reverse. Where's that come from?
No shortage of contaminated RT though, as usual. "We're rolling the trucks en route" indeed! Let alone readbacks from most of the other traffic, in a situation where punctilous readbacks are even more essential than usual.
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Where's there any suggestion the runway was contaminated? The METAR doesn't mention anything remotely suggesting that is possible and the videos show it isn't even raining.
Ditto re stowing speedbrakes and idle reverse. Where's that come from?
No shortage of contaminated RT though, as usual. "We're rolling the trucks en route" indeed! Let alone readbacks from most of the other traffic, in a situation where punctilous readbacks are even more essential than usual.
Ditto re stowing speedbrakes and idle reverse. Where's that come from?
No shortage of contaminated RT though, as usual. "We're rolling the trucks en route" indeed! Let alone readbacks from most of the other traffic, in a situation where punctilous readbacks are even more essential than usual.
The speed brakes extended normally, and the thrust reversers were deployed
to idle reverse thrust. The captain said that, shortly after touchdown, he retracted the
speedbrakes by the action of moving the speedbrake lever to its down and locked position,
which disabled the autobrakes. He did not “slow too much initially” because the runway
appeared dry, he wanted to expedite their time on the runway, and because he preferred
decelerating gradually for passenger comfort.
to idle reverse thrust. The captain said that, shortly after touchdown, he retracted the
speedbrakes by the action of moving the speedbrake lever to its down and locked position,
which disabled the autobrakes. He did not “slow too much initially” because the runway
appeared dry, he wanted to expedite their time on the runway, and because he preferred
decelerating gradually for passenger comfort.
for passenger comfort
I wonder how many incidents / accidents identify 'for passenger comfort' as a contributory factor ?
If the RCC was notified as 3/3/3, then "if unfamiliar with the runway, probably best to treat it as advertised" would be very good advice - FAA view.
EASA mandates the use of notified RCC in the before landing performance calculations.
If the RCC was notified as 3/3/3, then "if unfamiliar with the runway, probably best to treat it as advertised" would be very good advice - FAA view.
EASA mandates the use of notified RCC in the before landing performance calculations.
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Drifting to the MAX…
“With about 1,000 ft and 500 ft of runway remaining the airplane ground speeds were about 72 kts and 57 kts respectively. The right turn to exit the runway was initiated at about 39 kts groundspeed and the aircraft departed the end of the paved surface at about 22 kts.”
NTSB Aviation Investigation Preliminary Report - N27290, UAL2477
“With about 1,000 ft and 500 ft of runway remaining the airplane ground speeds were about 72 kts and 57 kts respectively. The right turn to exit the runway was initiated at about 39 kts groundspeed and the aircraft departed the end of the paved surface at about 22 kts.”
NTSB Aviation Investigation Preliminary Report - N27290, UAL2477
Captain should be demoted permanently for incompetence and lying to investigators.
WJ did the same thing in YUL a few years ago. Wet runway and trying to keep the speed up to exit at the end. Probably encountered wet rubber deposits.
It is real simple for runways where one would like to exit at the end in order to minimize taxi time. While one might typically minimize braking to get to the last taxiway quickly followed by an appropriate increase in braking for the exit, if it is wet, plan on slowing down and be at taxi turning speed at a taxiway before the last one.
Last edited by punkalouver; 24th Jun 2024 at 11:19.
Punkalouver,
You stated the Captain intentionally Lied and should be demoted. During critical phases of flight, it’s difficult to accurately determine when one started braking and at what point, If you are a Pilot, do you note exactly how far down the runway you begin braking? Hope your not a check-pilot.
You stated the Captain intentionally Lied and should be demoted. During critical phases of flight, it’s difficult to accurately determine when one started braking and at what point, If you are a Pilot, do you note exactly how far down the runway you begin braking? Hope your not a check-pilot.
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Punkalouver,
You stated the Captain intentionally Lied and should be demoted. During critical phases of flight, it’s difficult to accurately determine when one started braking and at what point, If you are a Pilot, do you note exactly how far down the runway you begin braking? Hope your not a check-pilot.
You stated the Captain intentionally Lied and should be demoted. During critical phases of flight, it’s difficult to accurately determine when one started braking and at what point, If you are a Pilot, do you note exactly how far down the runway you begin braking? Hope your not a check-pilot.
"The captain said he observed the reported runway surface condition codes when checking the automatic terminal information system (ATIS) via his electronic flight bag (EFB). For runway 26L and 26R, he recalled seeing codes of 3/3/3 and for runway 27 codes of 5/5/5. The actual runway surface condition codes being broadcasted on the ATIS for runway 27 at the time were 3/3/3 which according to the runway condition assessment matrix (RCAM) indicated the runway was slippery when wet and “braking deceleration is noticeably reduced for the wheel braking effort applied or directional control is noticeably reduced.”"
"The approach was conducted in instrument meteorological conditions (IMC) and, according to the crew, the airplane broke out of the clouds between 800 and 1,000 feet msl. They reported that visibility under the clouds was good, and the captain recalled that the runway appeared dry. The FO recalled that the runway appeared wet."
Maybe the runway didn't appear really wet but there is video of the pax exit from earlier in the thread and the pavement does not look dry.
As for me being a check pilot. If I were doing a check ride on this flight, I might take note of this:
"The captain changed the autobrake setting from 2 to 1 (which would command a reduced deceleration rate).
"The speed brakes extended normally, and the thrust reversers were deployed to idle reverse thrust. The captain said that, shortly after touchdown, he retracted the speedbrakes by the action of moving the speedbrake lever to its down and locked position, which disabled the autobrakes. He did not “slow too much initially” because the runway appeared dry, he wanted to expedite their time on the runway, and because he preferred decelerating gradually for passenger comfort."
"United Airlines supplementary flight crew procedures required for “Landing on Wet or Slippery Runway” stated in part: Use maximum reverse thrust as soon as possible after main wheel touchdown. Thrust reversers are most effective at high speed. Do not wait for the nose wheel to touchdown. Autobrake Stopping Determine the required distance to the desired runway exit point and select an autobrake setting of 3 or MAX, as appropriate."
While the ATIS was saying 3/3/3 in this case, it may not always be up to date. On a day where it is more likely that one could discover at the last minute that the runway is wet(cloudy/misty days), the pilot flying can always simply brief that if the runway appears wet upon becoming visual, I will ask for autobrake 3 and use max reverse.
Some parallels in terms of landing technique with this incident:
Aviation Investigation Report A15Q0075 - Transportation Safety Board of Canada (tsb.gc.ca)
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