LU9092
Topic Author
Posts: 125
Joined: Thu Oct 18, 2007 2:09 am

Low speed RTO

Fri Jun 01, 2018 11:49 pm

Hi all. My wife is on UA4979 at EWR. They began their takeoff roll and rejected at low speed. Flight crew announced "a warning light came on" and they went to the penalty box for 15 mins or so. Then another announcement that "maintenance control is gonna let us go." They attempted a second time to take off, and rejected again at low speed and are now headed back to the gate. Plane is an E145.

What sort of issues would typically cause an event like this?
 
32andBelow
Posts: 3485
Joined: Mon Sep 03, 2012 2:54 am

Re: Low speed RTO

Fri Jun 01, 2018 11:57 pm

Could be a configuration warning
 
LU9092
Topic Author
Posts: 125
Joined: Thu Oct 18, 2007 2:09 am

Re: Low speed RTO

Sat Jun 02, 2018 12:04 am

32andBelow wrote:
Could be a configuration warning


That wouldn't explain the second reject though. If something was broken enough to prevent the plane from being configured for takeoff, I kinda doubt there would even have been a first attempt.
 
GalaxyFlyer
Posts: 772
Joined: Fri Jan 01, 2016 4:44 am

Re: Low speed RTO

Sat Jun 02, 2018 12:25 am

Could be a switch in a component that gives the TAKE-OFF CONFIG warning. For example, while the flaps might indicate set for take-off on the gages; the sensor at the flap might not be met and send the message that configuration isn’t met.

In this case, crew could have, with maintenance input, reset the flaps in the hope the sensor was made.

GF
 
LU9092
Topic Author
Posts: 125
Joined: Thu Oct 18, 2007 2:09 am

Re: Low speed RTO

Sat Jun 02, 2018 12:42 am

GalaxyFlyer wrote:
Could be a switch in a component that gives the TAKE-OFF CONFIG warning. For example, while the flaps might indicate set for take-off on the gages; the sensor at the flap might not be met and send the message that configuration isn’t met.

In this case, crew could have, with maintenance input, reset the flaps in the hope the sensor was made.

GF


Ah, ok. I wasn't considering that there are would be multiple sensors reporting flap position.
 
BravoOne
Posts: 2715
Joined: Fri Apr 12, 2013 2:27 pm

Re: Low speed RTO

Sat Jun 02, 2018 3:14 pm

Don't dismiss the seriousness of a Low Speed RTO. The BA 777 at LAS is an excellent example of what can go wrong, go wrong.
 
KAUSpilot
Posts: 1674
Joined: Mon Jan 28, 2002 2:15 pm

Re: Low speed RTO

Sat Jun 02, 2018 5:51 pm

It could be anything, but my speculation would be an engine bleed or engine FADEC issue of some sort since it seems to happen when power is applied. I seriously doubt they would have two RTO's consecutively for the takeoff configuration warning unless something was wrong with that warning system. The only low speed RTO I ever did in 7 years on the E145 was for a cargo door open indication that for some reason only decided to come on shortly after takeoff thrust was applied. Also the E145 has a takeoff configuration test button that is pressed during the before takeoff checklist, so it's actually pretty hard to get a takeoff config RTO in that airplane unless you just skip the checklist.
 
LU9092
Topic Author
Posts: 125
Joined: Thu Oct 18, 2007 2:09 am

Re: Low speed RTO

Mon Jun 04, 2018 7:39 pm

KAUSpilot wrote:
It could be anything, but my speculation would be an engine bleed or engine FADEC issue of some sort since it seems to happen when power is applied. I seriously doubt they would have two RTO's consecutively for the takeoff configuration warning unless something was wrong with that warning system. The only low speed RTO I ever did in 7 years on the E145 was for a cargo door open indication that for some reason only decided to come on shortly after takeoff thrust was applied. Also the E145 has a takeoff configuration test button that is pressed during the before takeoff checklist, so it's actually pretty hard to get a takeoff config RTO in that airplane unless you just skip the checklist.


Thanks for the insight!
 
amishfarmer
Posts: 8
Joined: Wed May 30, 2018 2:37 pm

Re: Low speed RTO

Wed Jun 06, 2018 5:41 pm

"Warning light" is Pilot to Passenger code for alot of things. It could be alot of electrical or mechanical things in the aircraft, I don't know what the weather is at the airport but it could be wind shear as well. The Pilot might just say a "warning light" because saying wind shear sounds scarier than a warning light.
Again this is 100% speculation of the actual cause. I just know from experience (I'm aircraft maintenance 20+years) Pilots tend to use "safe"phrases or terms so it doesn't spook the passengers.
 
AA737-823
Posts: 5301
Joined: Wed Mar 01, 2000 11:10 am

Re: Low speed RTO

Wed Jun 06, 2018 11:56 pm

LU9092 wrote:
GalaxyFlyer wrote:
Could be a switch in a component that gives the TAKE-OFF CONFIG warning. For example, while the flaps might indicate set for take-off on the gages; the sensor at the flap might not be met and send the message that configuration isn’t met.

In this case, crew could have, with maintenance input, reset the flaps in the hope the sensor was made.

GF


Ah, ok. I wasn't considering that there are would be multiple sensors reporting flap position.


Also consider that, while GalaxyFlyer's explanation is certainly one possibility, there are more items sensed by the Takeoff Config Warning System than just flap position. Parking brake and Stab Trim, for example. Stab position sensors are in the tail, near the engines, so a wonky sensor suddenly subjected to high vibes from takeoff power COULD be a culprit.
In my 500+ revenue flights (and 200+ additional flights as a traveling mechanic), I've never experienced an RTO. I agree that it's odd a second attempt would be made, unless a speedy MEL was applied, that turned out not to have eliminated the issue.
`\_(~,~)_/`
 
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PowerliftDrsTX
Posts: 16
Joined: Tue Jan 02, 2018 2:51 pm

Re: Low speed RTO

Thu Jun 07, 2018 1:17 pm

LU9092 wrote:
Hi all. My wife is on UA4979 at EWR. They began their takeoff roll and rejected at low speed. Flight crew announced "a warning light came on" and they went to the penalty box for 15 mins or so. Then another announcement that "maintenance control is gonna let us go." They attempted a second time to take off, and rejected again at low speed and are now headed back to the gate. Plane is an E145.

What sort of issues would typically cause an event like this?



As an EMB145 pilot myself, the first guess would have been a config on the first go, as someone mentioned. The second has me perplexed. Could be a failure to start pressurization (CPAM issue) but that would happen at a higher wheel speed than what you described. hmm......its been a few years but beyond that and/or FADEC issues (power not making set, or uneven etc)....thats really the first set of callouts in that plane....set thrust, thrust set......would happen early in the takeoff.

The 145 is suceptible to nuisance faults. I remember once we got a "bleed leak" indication during taxi that we isolated and then "rebooted" so to speak and then got no indication. If there had really been a leak, we would have continued to get warned. Maybe they had a "bleed leak" indication that went away when they started to mess with it in the penalty box. In that circumstance, as is my experience, MX would let you go if the warning went away.
 
User avatar
PowerliftDrsTX
Posts: 16
Joined: Tue Jan 02, 2018 2:51 pm

Re: Low speed RTO

Thu Jun 07, 2018 1:20 pm

GalaxyFlyer wrote:
Could be a switch in a component that gives the TAKE-OFF CONFIG warning. For example, while the flaps might indicate set for take-off on the gages; the sensor at the flap might not be met and send the message that configuration isn’t met.

In this case, crew could have, with maintenance input, reset the flaps in the hope the sensor was made.

GF


The 145 has a "takeoff config" button that you press right before takeoff that would have caught flap discrepancies. pressing the button would have gotten a "TAKEOFF...O K" or a "TAKEOFF.....FLAPS" message

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