Why were they coming in with a tailwind? I thought ATC were the ones that told them which direction to approach?
It was a 5kt tailwind. Runway 14 was the only runway with an ILS approach. 23 is under construction and the ILS is out. Maybe they thought this was their best chance of a successful landing.
Probably more than you want in a 744 on a wet 7,700 foot runway, which is kinda confirmed by the airplane being snapped in half sitting on the grass. Hindsight 20/20, of course.
It really depends on what their calculated landing distance was and what margin for error they used. Runway looks wet, but not standing water wet. Where was their touchdown point?
I obviously don't have 744 landing numbers in front of me, but for a 737 and a 767 a 5 know tailwind would add roughly 500ft to the landing distance, depending on the runway surface condition.
Based on the time of the incident (just after 5am local time) they likely made their calculations based on the 4am ATIS (0800 UTC) which shows a very slight headwind. 210/10kts. The ceiling was also 500ft so you can understand why they wanted rwy 14 for the only usable ILS on the field.
The more recent hourly shows that the winds swung to 230\13kts. A small tailwind. Then the special came out at 5:12 am local time showing 230\11G18kts which ast the 18kt gust mark gives you the closest to the 5kt tailwind.
What were the actual winds at the time of the incident? I sure as hell don't know. What were they given by ATC just prior to landing? Don't know that either. What was the margin for error on their landing distance calculation given the winds were shifting from headwind to tail wind? Beats me. Was the runway more slippery than thought? Who knows. With a gusty crosswind, which can at times affect speed control, how high above or below ref speed was touchdown?
Sure there is some airmanship involved when electing to land with a tail wind. But the numbers either work, or they don't.
Since the interwebz is the home to all armchair quarterbacks, my guess is if the unconfirmed tailwind factored into the incident at all, it factored very little.
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To clarify, I don't claim that the tailwind is the reason this happened. It'd make far more sense to attribute it to the 7,700 feet. I've been around long enough to know that, in actual fact, we know nothing and can't attribute it to anything yet.
i'll elevate myself above an armchair quarterback because we do have the numbers in front of us here (just ran them in the computer) and they suggest a 7,700 foot runway leaves a less-than-ideal margin of error for a 744 even at max brake and full reverse. Period.
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Wondering what happened to the flight from YYC to YHZ that was diverted to Ottawa because of this accident? Will the flight eventually continue today and bring home the passengers stuck in YHZ to YYC? Thanks
Last edited by DylanScores; 11-07-2018 at 02:47 PM.
Wondering what happened to the flight from YYC to YHZ that was diverted to Ottawa because of this accident? Will the flight eventually continue today and bring home the passengers stuck in YHZ to YYC? Thanks
Eventually. The Edmonton flight diverted too, they're working on it but crews and airplanes were way out of position so it'll take a couple of days till everything is good.
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Haven't listened to the whole thing yet but what's distressing is she was in that position by herself for 40 minutes according to this article. I could have sworn the FAA addressed this a decade ago after the Comair crash at LEX.
It really depends on what their calculated landing distance was and what margin for error they used. Runway looks wet, but not standing water wet. Where was their touchdown point?
I obviously don't have 744 landing numbers in front of me, but for a 737 and a 767 a 5 know tailwind would add roughly 500ft to the landing distance, depending on the runway surface condition.
Based on the time of the incident (just after 5am local time) they likely made their calculations based on the 4am ATIS (0800 UTC) which shows a very slight headwind. 210/10kts. The ceiling was also 500ft so you can understand why they wanted rwy 14 for the only usable ILS on the field.
The more recent hourly shows that the winds swung to 230\13kts. A small tailwind. Then the special came out at 5:12 am local time showing 230\11G18kts which ast the 18kt gust mark gives you the closest to the 5kt tailwind.
What were the actual winds at the time of the incident? I sure as hell don't know. What were they given by ATC just prior to landing? Don't know that either. What was the margin for error on their landing distance calculation given the winds were shifting from headwind to tail wind? Beats me. Was the runway more slippery than thought? Who knows. With a gusty crosswind, which can at times affect speed control, how high above or below ref speed was touchdown?
Sure there is some airmanship involved when electing to land with a tail wind. But the numbers either work, or they don't.
Since the interwebz is the home to all armchair quarterbacks, my guess is if the unconfirmed tailwind factored into the incident at all, it factored very little.
I always enjoy the VASAvation videos of incidents like these.
I always enjoy the VASAvation videos of incidents like these.
I love how calm everyone is. The conversation is basically:
ATC: Would you like some more coffee, sir?
Plane: Oh, yes please.
ATC: What did you take in it again, milk or cream?
Plane: Just sugar and requesting full emergency assistance.
ATC: Sending full emergency assistance, and I'll be right back with your coffee and sugar.
__________________ "Calgary Flames is the best team in all the land" - My Brainwashed Son
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Haven't listened to the whole thing yet but what's distressing is she was in that position by herself for 40 minutes according to this article. I could have sworn the FAA addressed this a decade ago after the Comair crash at LEX.
That's deeply troubling and not what would be expected in an airport as busy as Vegas. The article does state that there was another controller but he was on break at the time.
"The FAA will require two controllers to be in the tower cab working traffic until a certain time based on shift periods and traffic levels. The policy will take effect today."
