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LAX772LR
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Reverse Thrust on high-speed exit?

Mon Aug 20, 2018 6:24 am

Interesting video of a JL aircraft landing at CTS and still in heavy reverse as it exits the runway... causing some serious snow-blow.

https://www.youtube.com/watch?v=IHFQNwVBgHM

Is this common? I admit to never having noticed anyone else doing it. Seems a real FOD danger.

Anyone?
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a320fan
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Re: Reverse Thrust on high-speed exit?

Mon Aug 20, 2018 6:30 am

Seen it quite a few times myself, only on highspeeds though.
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BlueberryWheats
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Re: Reverse Thrust on high-speed exit?

Mon Aug 20, 2018 6:44 am

Being snowy conditions and therefore obviously could be icy, could it be that they wanted to avoid using the brakes where possible while still at high speed turnoff speeds?
 
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CrimsonNL
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Re: Reverse Thrust on high-speed exit?

Mon Aug 20, 2018 7:04 am

I see it every now and then, sometimes even continuing when they are well on the taxiway too.
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aeropix
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Re: Reverse Thrust on high-speed exit?

Mon Aug 20, 2018 7:19 am

Sometimes you simply get distracted with something like a radio call, or finding the correct exit etc. as all humans do and simply may have forgotten to stow the reversers.
 
arcticcruiser
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Re: Reverse Thrust on high-speed exit?

Mon Aug 20, 2018 7:32 am

aeropix wrote:
Sometimes you simply get distracted with something like a radio call, or finding the correct exit etc. as all humans do and simply may have forgotten to stow the reversers.


No.
 
mmo
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Re: Reverse Thrust on high-speed exit?

Mon Aug 20, 2018 7:53 am

Is it common? No

But if you watch closely, it would appear as if they went to idle reverse just as they turned off on the hi-speed exit. At about 1:45 the reverses go to stowed so there were only a few seconds of reverse. If you watch the video, you can see just how much is ingested into the engines. Much less than you would expect.

I will try to find the exact wording for the restrictions but IIRC, you had to be in idle reverse by 60 KIAS. He certainly met that restriction. The carriers where I have flown the 400 had an SOP where idle reverse was at 80 KIAS and stowed by 60. However, there was always the caveat of "if the PIC determined added reverse thrust was needed" then it was idle by 60.
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reltney
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Re: Reverse Thrust on high-speed exit?

Mon Aug 20, 2018 10:17 am

I leave it in idle reverse as I make a high speed turnoff. On a slick taxiway, usually not grooved like runways, the slight learch coming out of reverse breaks traction and I hate that so I leave it at idle reverse till I have the plane moving down the parallel. The md80is the worst about it.
Again, it’s at idle and during icy snowy conditions, it blows nothing...
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Pontius
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Re: Reverse Thrust on high-speed exit?

Mon Aug 20, 2018 2:47 pm

That’s about where I would have stowed the reversers given the condidtions. Our SOP allows idle reverse down to taxi speed, but one does whatever is required to keep the machine out of the dirt.

Runway/taxiway traction on a snowy day can be highly variable from spot to spot. One highspeed may have been used more than another, and often the runway conditions beyond the most frequently used turnoff worsen badly.

Taxiing a jet is a terribly awkward affair. Imagine a car, lifted like a monster truck, with only rear wheel braking, bald tires on the front steering wheels, that is forever being blown forward as though pushed by a hurricane. One must be proactive about deceleration.
 
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ro1960
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Re: Reverse Thrust on high-speed exit?

Mon Aug 20, 2018 7:56 pm

Something red is leaking from R2...
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BWIAirport
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Re: Reverse Thrust on high-speed exit?

Wed Aug 22, 2018 12:12 pm

aeropix wrote:
Sometimes you simply get distracted with something like a radio call, or finding the correct exit etc. as all humans do and simply may have forgotten to stow the reversers.

Correct me if I'm wrong, but isn't the thrust reverse typically deactivated around 60 knots? Even if not, like the spoilers, they'd close when any thrust is applied. It's not like the flaps or landing/strobe lights where the pilots can just forget them. The plane won't allow it.
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Flow2706
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Re: Reverse Thrust on high-speed exit?

Wed Aug 22, 2018 6:59 pm

BWIAirport wrote:
Correct me if I'm wrong, but isn't the thrust reverse typically deactivated around 60 knots? Even if not, like the spoilers, they'd close when any thrust is applied. It's not like the flaps or landing/strobe lights where the pilots can just forget them. The plane won't allow it.

I agree that it’s uncommon to forget to stow the reverses, but at least on Airbus they are not automatically deactivated. While the recommendation (or normal procedure) says that you should be in idle reverse at 70kts they can be used until coming to a stop in an emergency/RTO if needed according to the manual (that is for A320). It’s true that it’s not possible to apply any forward thrust when Reverse is selected.
 
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Re: Reverse Thrust on high-speed exit?

Wed Aug 22, 2018 8:02 pm

arcticcruiser wrote:
aeropix wrote:
Sometimes you simply get distracted with something like a radio call, or finding the correct exit etc. as all humans do and simply may have forgotten to stow the reversers.


No.


Actually that is quite likely exactly what it was. I have seen it myself countless times, where the other pilot has held onto reverse far longer than necessary (usually due to a distraction or fixated on getting stopped).
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WPvsMW
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Re: Reverse Thrust on high-speed exit?

Wed Aug 22, 2018 8:58 pm

Is the lurch at 1:10 from going into idle reverse, or did the pilot hit the brakes?
 
arcticcruiser
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FRe: Reverse Thrust on high-speed exit?

Wed Aug 22, 2018 10:26 pm

WPvsMW wrote:
Is the lurch at 1:10 from going into idle reverse, or did the pilot hit the brakes?


Brakes. Reverse does not cause a lurch.

barney captain wrote:
arcticcruiser wrote:
aeropix wrote:
Sometimes you simply get distracted with something like a radio call, or finding the correct exit etc. as all humans do and simply may have forgotten to stow the reversers.


No.


Actually that is quite likely exactly what it was. I have seen it myself countless times, where the other pilot has held onto reverse far longer than necessary (usually due to a distraction or fixated on getting stopped).


Well, respectfully disagree. Sure some people stay in reverse longer than necessary, or start in reverse idle then all of a sudden pull in thrust below 100 kts which is pretty useless. Incidentally the 737 is the smallest jet I have flown, but the one with the worst stopping capability.
 
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Re: Reverse Thrust on high-speed exit?

Thu Aug 23, 2018 10:41 pm

Flow2706 wrote:
BWIAirport wrote:
Correct me if I'm wrong, but isn't the thrust reverse typically deactivated around 60 knots? Even if not, like the spoilers, they'd close when any thrust is applied. It's not like the flaps or landing/strobe lights where the pilots can just forget them. The plane won't allow it.

I agree that it’s uncommon to forget to stow the reverses, but at least on Airbus they are not automatically deactivated. While the recommendation (or normal procedure) says that you should be in idle reverse at 70kts they can be used until coming to a stop in an emergency/RTO if needed according to the manual (that is for A320). It’s true that it’s not possible to apply any forward thrust when Reverse is selected.


Unlike Airbus, Boeing has seperate levers for Reverse Thrust. Your hand has to be on the levers pretty much at all times. Not really possible for them to "forget" to stow it.

Boeing recommendation is to stow the reversers by 60 knots to minimize risk of FOD. However, they can be used all the way down to 0 knots if stopping on the runway is in doubt.

You can only pull the Reverse Thrust Levers when the main Thrust Levers are at idle. Not possible on Boeing either to apply forward thrust when reverse is activated. Wouldn't be physically possible on the engine either since the thrust reverse are open.
 
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Re: Reverse Thrust on high-speed exit?

Fri Aug 24, 2018 3:00 am

BoeingGuy wrote:
Flow2706 wrote:
BWIAirport wrote:
Correct me if I'm wrong, but isn't the thrust reverse typically deactivated around 60 knots? Even if not, like the spoilers, they'd close when any thrust is applied. It's not like the flaps or landing/strobe lights where the pilots can just forget them. The plane won't allow it.

I agree that it’s uncommon to forget to stow the reverses, but at least on Airbus they are not automatically deactivated. While the recommendation (or normal procedure) says that you should be in idle reverse at 70kts they can be used until coming to a stop in an emergency/RTO if needed according to the manual (that is for A320). It’s true that it’s not possible to apply any forward thrust when Reverse is selected.


Unlike Airbus, Boeing has separate levers for Reverse Thrust. Your hand has to be on the levers pretty much at all times. Not really possible for them to "forget" to stow it.

Boeing recommendation is to stow the reversers by 60 knots to minimize risk of FOD. However, they can be used all the way down to 0 knots if stopping on the runway is in doubt.

You can only pull the Reverse Thrust Levers when the main Thrust Levers are at idle. Not possible on Boeing either to apply forward thrust when reverse is activated. Wouldn't be physically possible on the engine either since the thrust reverse are open.


Hang on... While the 320 series does not have reverse levers, later Airbuses do. You can see them in front of the thrust levers in these pics. The levers work the same as on Boeing, with a detent for idle reverse, and further pull for more than idle. The lockout logic is also the same, with no reverse except from idle etc...

On the 320, there are lockout levers but reverse is applied by moving the thrust levers themselves behind the idle detent, as opposed to pulling for reverse. So there's still a lockout mechanism.

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cougar15
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Re: Reverse Thrust on high-speed exit?

Fri Aug 24, 2018 7:53 am

It might be a bit of a local thing in regards to SOPs. Past experience at a number of European airports, this was actually pretty much standard.
One particular example is Cologne/CGN and/or DXB for example. If you check out some of the Vid´s on youtube, it is very much routine. I always saw it as an efficiency thing.
CGN would approve ´high speed´ on approach/landing... so above 250KT below 10K FT , but then of course - one hand washes the other - expect you to vacate ASAP. And I doubt the jockeys involved ´forgot´ abour, or where busy with other things in regards to the reversers.....

And that is what everyone did, mind you.. the taxiways are built for it, so it causes no issues. And it is not a local thing either (german skippers only) , CGN is the second biggest UPS/5X hub globally and even our American friends are happy to comply (with a huge amount of flights in there every night). Again, watch some of the videos on YT out there, it seems rather standard as a process.

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Starlionblue
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Re: Reverse Thrust on high-speed exit?

Fri Aug 24, 2018 10:45 am

cougar15 wrote:
It might be a bit of a local thing in regards to SOPs. Past experience at a number of European airports, this was actually pretty much standard.
One particular example is Cologne/CGN and/or DXB for example. If you check out some of the Vid´s on youtube, it is very much routine. I always saw it as an efficiency thing.
CGN would approve ´high speed´ on approach/landing... so above 250KT below 10K FT , but then of course - one hand washes the other - expect you to vacate ASAP. And I doubt the jockeys involved ´forgot´ abour, or where busy with other things in regards to the reversers.....

And that is what everyone did, mind you.. the taxiways are built for it, so it causes no issues. And it is not a local thing either (german skippers only) , CGN is the second biggest UPS/5X hub globally and even our American friends are happy to comply (with a huge amount of flights in there every night). Again, watch some of the videos on YT out there, it seems rather standard as a process.

Different cultures, different ideas to drive efficency!


Plenty of places will offer high speed below 10000, or give when asked. However high speed under 10000 does not mean you'll have a higher than normal speed on final, and certainly not on touchdown.

Computed vapp depends on weight and conditions, not how fast you got to the FAF. Whether you were at 250 or 300 knots at 5000 feet, your touchdown speed will be the same.
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slcguy
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Re: Reverse Thrust on high-speed exit?

Fri Aug 24, 2018 2:02 pm

Yes, reverse thrust is normally used on landing down to 80kts getting out of by 60kts but they can be used slower than that if needed. Slick runways and taxiway exits are a good example, partial reverse can often help when braking is limited. I've also seen reverse used while taxiing to control speed in both air carrier and business jet aircraft. Reverse thrust can also be used to back an aircraft back from the gate (most commonly done on the older high mounted rear engine types, DC9/MD80/B727 due to them less likely to ingest FOD than wing mounted types). As far as I know pilots can apply reverse any time they want (not in flight of course) in Boeings, not sure about Airbus.
Last edited by slcguy on Fri Aug 24, 2018 2:21 pm, edited 1 time in total.
 
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Starlionblue
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Re: Reverse Thrust on high-speed exit?

Fri Aug 24, 2018 2:14 pm

slcguy wrote:
Yes, reverse thrust is normally used on landing down to 80kts getting out of by 60kts but they can be used slower than that if needed. Slick runways and taxiway exits are a good example, partial reverse can often help when braking is limited. I've also seen reverse used while taxiing to control speed in both air carrier and business jet aircraft. Reverse thrust can also be used to back an aircraft back from the gate (most commonly done on the older high mounted rear engine types, DC9/MD80/B727 due to them less likely to ingest FOD than wing mounted types). As far I know pilots can apply reverse any time they want (not in flight of course) in Boeings, not sure about Airbus.


On the 330 and 350, it is recommended to go to idle reverse at 70 knots. This doesn't mean you can't use full reverse to a full stop, but there better be a good reason or you'll be having tea and biscuits with the chief pilot, most likely without the biscuits.
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Re: FRe: Reverse Thrust on high-speed exit?

Fri Aug 24, 2018 11:45 pm

arcticcruiser wrote:
WPvsMW wrote:
Is the lurch at 1:10 from going into idle reverse, or did the pilot hit the brakes?


Brakes. Reverse does not cause a lurch.

barney captain wrote:
arcticcruiser wrote:

No.


Actually that is quite likely exactly what it was. I have seen it myself countless times, where the other pilot has held onto reverse far longer than necessary (usually due to a distraction or fixated on getting stopped).


Well, respectfully disagree. Sure some people stay in reverse longer than necessary, or start in reverse idle then all of a sudden pull in thrust below 100 kts which is pretty useless. Incidentally the 737 is the smallest jet I have flown, but the one with the worst stopping capability.


I guess my last FO didn't get the memo then. Going through 40kts he still had full reverse selected - fixated on the next highspeed I guess. I had to make a "reverse" call to get him to stow them.I've seen this more times than I can count - brakes and reverse trying to get slowed, not realizing the reverse is only making noise at this point. The brain is only thinking "stop", so both brakes and reverse stay engaged. It happens.
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MassAppeal
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Re: Reverse Thrust on high-speed exit?

Sat Aug 25, 2018 9:41 pm

I see a bunch of private jets taxiing long distances with their T/R's deployed.
 
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tb727
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Re: Reverse Thrust on high-speed exit?

Sun Aug 26, 2018 1:49 am

MassAppeal wrote:
I see a bunch of private jets taxiing long distances with their T/R's deployed.


That's because they would have to ride the brakes due to going too fast with the thrust of both engines.

I use idle reverse on high speed exits all the time. There are some guys that have the school of thought that there is an increase risk of FOD since it's not on a runway and there could be more debris because the areas aren't swept as often but to each his own. Not a problem in my mind at large, busy airports that would have high speed exits in constant use.

I can also admit that on the Airbus I have pulled off the runway and forgot I was in idle reverse at a near stop while turning onto the parallel. It happened after clearing and awaiting some further instruction then realized it when I went to push the thrust levers forward to start taxiing and they clicked out of the reverse detent.
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