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-   -   Experiences on UA with aborted takeoffs, landings, go-arounds, .... [Consolidated] (https://www.flyertalk.com/forum/united-airlines-mileageplus/1730679-experiences-ua-aborted-takeoffs-landings-go-arounds-consolidated.html)

aussieinsf Jan 16, 15 9:34 pm

Experiences on UA with aborted takeoffs, landings, go-arounds, .... [Consolidated]
 
737-800, aborted mid-takeoff as we were moving quickly down the runway. Captain said that a sensor indicated a door was open (however the door was not actually open). Taxi'd off the active portion of the runway quickly then determined that they needed to return to the terminal. Returned to the gate and have been here about two hours so far while they address an issue with the door sensor and do a safety check protocol required after a "high energy stop" or some other terminology that was mentioned. They are still trying to fix something in the back. Crew is fresh and say they have time left for the flight to operate and take us to SFO.

Close to the 3 hour time from push back they let people get off and go into the terminal.

Flight arrival time now showing 2:43am :(

sbm12 Jan 16, 15 9:38 pm

Sounds like they're doing everything exactly like they should be.

WineCountryUA Jan 16, 15 9:49 pm


Originally Posted by aussieinsf (Post 24182404)
...do a safety check protocol required after a "high energy stop" ...

A significant part of that is a brake inspection.

Glad all is well otherwise.

aussieinsf Jan 16, 15 10:07 pm

They moved us to a new aircraft. We are boarding now.

kevinsac Jan 16, 15 10:37 pm

^ sounds like everything went as directed. Good news ^

RobOnLI Jan 16, 15 10:40 pm

The delay was caused by the door sensor and not the brake check IMO.

I had an aborted take off (with Channel 9 on!) on a 738 DEN-SEA a year or two ago. Midway through the roll the runway sensors went off indicating an unauthorized vehicle on the runway. Tower told the pilot to abort so he hits the brakes hard and keeps the plane on the center line the whole time. After coming to a stop we got off the runway and parked there for about 30 minutes while the brakes cooled down. Once they did they were inspected, considered good and we got back in line for take off. Never went back to the terminal which was a bonus. Note: there was dense fog in DEN at the time so the tower had to rely on the sensors at the runway thresholds instead of their eyes. Maybe a bad sensor that day.

-RM

channa Jan 16, 15 11:01 pm

Estimated due in at 3:24 AM now. A westbound redeye!

4:45 delayed on a mechanical. Compensation is in order for this one.

aussieinsf Jan 19, 15 10:06 am

I think RobonLI was right - the move to a new aircraft came after two hours of UA maintenance trying to work on the door. It did not appear the brakes were the reason.

As with other MX issues I've experienced with United, I appreciated the transparency from the captain and that he was clearly empowered to put safety first at all times.

Channa - We got in around 3:30am, a true west coast red-eye. UA offered $175 or 8,750 miles compensation. (I'm a Plat flying on a low economy fare class)
I thought that was fair.

mherdeg Jan 19, 15 10:14 am

As a layperson it's difficult for me to understand that on the ground, aircraft have a critical "V1" speed below which it's safe to abort a takeoff, and after which you should always continue takeoff, even if there is an engine failure. I do know that the scary part of a takeoff is near the middle to end of the runway as you approach that speed and the pilot's options dwindle, but conceptually the way it works has some gaps for me…

I know the calculation of V1 speed is done on a per-equipment basis and considers things like "above this speed, it will not be possible to stop the plane because brakes aren't designed to do that much work", but it seems weird that this calculation doesn't include runway length or takeoff weight.

Instead, in what seems weird to me, "minimum required runway length" is calculated as a function of aircraft weight and V1 — so the a/c's rated maximum refusal speed determines how much room it needs, and not the other way around.

Why not say "oh boy, we've got 6 more miles of runway in front of us, even though my V1 is 124 mph and I'm going 126 mph, I can probably safely decelerate in the space available?"

Maybe a question for the 'ask a pilot' thread. Nice to hear that in this case, the pilot safely made the right call during an important phase of flight.

warreng24 Jan 19, 15 11:26 am


Originally Posted by RobOnLI (Post 24182586)
I had an aborted take off (with Channel 9 on!) on a 738 DEN-SEA a year or two ago.

738's have Channel 9?

PropClear Jan 19, 15 11:33 am


Originally Posted by mherdeg (Post 24194649)
As a layperson it's difficult for me to understand that on the ground, aircraft have a critical "V1" speed below which it's safe to abort a takeoff, and after which you should always continue takeoff, even if there is an engine failure. I do know that the scary part of a takeoff is near the middle to end of the runway as you approach that speed and the pilot's options dwindle, but conceptually the way it works has some gaps for me…

I know the calculation of V1 speed is done on a per-equipment basis and considers things like "above this speed, it will not be possible to stop the plane because brakes aren't designed to do that much work", but it seems weird that this calculation doesn't include runway length or takeoff weight.

Instead, in what seems weird to me, "minimum required runway length" is calculated as a function of aircraft weight and V1 — so the a/c's rated maximum refusal speed determines how much room it needs, and not the other way around.

Why not say "oh boy, we've got 6 more miles of runway in front of us, even though my V1 is 124 mph and I'm going 126 mph, I can probably safely decelerate in the space available?"

Maybe a question for the 'ask a pilot' thread. Nice to hear that in this case, the pilot safely made the right call during an important phase of flight.

Then you're having to rely on the crew knowing what their V1 is on every different runway (plus weather conditions, altitude, etc). Prolly a lot safer giving them one number, knowing that while scary, taking off above that speed has been tested extensively and can get them back around to land.

FWAAA Jan 19, 15 11:56 am


Originally Posted by PropClear (Post 24195171)
Then you're having to rely on the crew knowing what their V1 is on every different runway (plus weather conditions, altitude, etc). Prolly a lot safer giving them one number, knowing that while scary, taking off above that speed has been tested extensively and can get them back around to land.

And for the aftermath of poor-decision making by the pilots and subsequent crash after V1, see:

http://www.flightglobal.com/news/art...sh-faa-407032/

They aborted the takeoff after the plane was airborne.

chiph Jan 19, 15 12:15 pm


As a layperson it's difficult for me to understand that on the ground, aircraft have a critical "V1" speed below which it's safe to abort a takeoff, and after which you should always continue takeoff, even if there is an engine failure. I do know that the scary part of a takeoff is near the middle to end of the runway as you approach that speed and the pilot's options dwindle, but conceptually the way it works has some gaps for me…

I know the calculation of V1 speed is done on a per-equipment basis and considers things like "above this speed, it will not be possible to stop the plane because brakes aren't designed to do that much work", but it seems weird that this calculation doesn't include runway length or takeoff weight.

Instead, in what seems weird to me, "minimum required runway length" is calculated as a function of aircraft weight and V1 — so the a/c's rated maximum refusal speed determines how much room it needs, and not the other way around.

Why not say "oh boy, we've got 6 more miles of runway in front of us, even though my V1 is 124 mph and I'm going 126 mph, I can probably safely decelerate in the space available?"

Maybe a question for the 'ask a pilot' thread. Nice to hear that in this case, the pilot safely made the right call during an important phase of flight.

Originally Posted by PropClear (Post 24195171)
Then you're having to rely on the crew knowing what their V1 is on every different runway (plus weather conditions, altitude, etc). Prolly a lot safer giving them one number, knowing that while scary, taking off above that speed has been tested extensively and can get them back around to land.

The V speeds (e.g., V1, V2, Vr, Vref, etc) are calculated per-takeoff by the flight management system (FMS) and takes into consideration the runway (including direction), winds, temperature, conditions (e.g., wet/dry), weight, etc.

The crew has the #s before takeoff and they're also displayed on the airspeed tape/display.

Also see http://en.wikipedia.org/wiki/Balanced_field_takeoff

eng3 Jan 19, 15 2:51 pm


Originally Posted by chiph (Post 24195469)
The V speeds (e.g., V1, V2, Vr, Vref, etc) are calculated per-takeoff by the flight management system (FMS) and takes into consideration the runway (including direction), winds, temperature, conditions (e.g., wet/dry), weight, etc.

The crew has the #s before takeoff and they're also displayed on the airspeed tape/display.

Also see http://en.wikipedia.org/wiki/Balanced_field_takeoff

Thanks! From all the episodes of Air Disasters I've watched, I was pretty sure that it took weather, weight, etc into consideration and is not done using a computer. I'm also pretty sure it is something discussed with the crew in the pre-flight briefing. I remember some "incidents" that were a result of the crew not fully "in-sync" regarding what speed V1 is. (Although, I think modern technology has helped reduce these types of errors)

Also, if I recall, after a rejected takeoff, you might might burst a tyre or overheat the brakes, or have something catch on fire. Then you have to investigate the actual cause of the rejected takeoff. Then get back in line. Basically alot of delays, but better safe than sorry.


Originally Posted by FWAAA (Post 24195328)
And for the aftermath of poor-decision making by the pilots and subsequent crash after V1, see:

http://www.flightglobal.com/news/art...sh-faa-407032/

They aborted the takeoff after the plane was airborne.

I'm no pilot, but if I recall, you aren't suppose to abort the takeoff after V1 unless you don't think your plane is capable of safe flight. I'm sure this sort of thing is drilled into pilots during training. Ofcourse its easy for us to come to conclusions, we weren't in their seats

choefman Aug 21, 15 8:25 am

UA1478 IAH-BOS: Aborted takeoff due to engine fire [20 August, 2015]
 
Got that last minute upgrade to first after boarding, call it the walk of shame or fame on UA1478 from Houston to Boston last night. Gotta love it!

Unfortunately on takeoff the plane behind us in line for take off, reported flames coming out of one of our engines and takeoff was aborted very last second...

Nice work on the crew side, I must say, very professional, captain quickly reassured everyone things were ok, the flight attendants walked the cabin to reassure people and the 1K service desk had me rebooked before we got back to the gate. I got lucky, got on a flight just 30 minutes later and got back home barely late.

Not sure what happened to UA1478 though, noticed the flight left a few hours later but I don't know if that was the same airplane or if the switched.


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