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highflyer9790
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747 Reverse Thrust Doesn't Stop (Video)

Mon Feb 12, 2007 4:09 am

Not sure how else to title this, but after watching this video,

http://www.flightlevel350.com/Aircra..._Airlines_Aviation_Video-7917.html

The 747 touches down and reversers are deployed as usual, yet instead of being stowed around 60kts they continue through taxiing at taxi speeds. you can see the 747 turn off the runway with reversers still activated around 2:30 mark.

i wouldnt think this is SOP, as FOD is highly likely at slow speeds with reverse. My only thought is that it had something to do with the snow...maybe special winter ops? stuck reversers? (all four engines - doubt it)

anyone know?


highflyer
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dl757md
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Mon Feb 12, 2007 4:27 am

Quoting HighFlyer9790 (Thread starter):
i wouldnt think this is SOP, as FOD is highly likely at slow speeds with reverse. My only thought is that it had something to do with the snow...maybe special winter ops? stuck reversers? (all four engines - doubt it)

I don't know of any reason why they would do this. I'm not a pilot though. One thing this video demonstrates quite well is the potential for FOD ingestion due to T/R deployment at low speeds. It's very interesting watching the snow blowing around and getting sucked up in the inlet of the engines. Perhaps the pilots wanted to give the pax a show of all the blowing snow.

DL757Md
757 Most beautiful airliner in the sky!
 
highflyer9790
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Mon Feb 12, 2007 4:51 am

Quoting Dl757md (Reply 1):
don't know of any reason why they would do this.



Quoting Dl757md (Reply 1):
One thing this video demonstrates quite well is the potential for FOD ingestion due to T/R deployment at low speeds.

Yea thats why i cant figure out the reason for doing this.
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airfoilsguy
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Mon Feb 12, 2007 7:06 am

Wow, I leave for the weekend and the place were you enter comment's on threads totally change.


As for the video the pilot probably didn't push the thrust reverse levers all the way back to their park position. Something probably distracted him.
It's not a near miss it's a near hit!!
 
highflyer9790
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Mon Feb 12, 2007 8:11 am

Quoting Airfoilsguy (Reply 3):
As for the video the pilot probably didn't push the thrust reverse levers all the way back to their park position. Something probably distracted him.

uless im wrong, wouldnt this big of a mistake have led to an immediate sim session and refresher? suspension even? something like that is REALLY hard to be distracted from...idk maybe...
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ThrottleHold
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Mon Feb 12, 2007 8:31 am

Quoting HighFlyer9790 (Reply 4):

uless im wrong, wouldnt this big of a mistake have led to an immediate sim session and refresher? suspension even? something like that is REALLY hard to be distracted from...idk maybe...

Yes, you are wrong! Forgetting to stow them because you got distracted is a minor hiccup.
 
airfoilsguy
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Mon Feb 12, 2007 9:43 am

I am making this post to appease my girlfriend who is always right and I who I have much to learn from. My earlier statement was incorrect and I wish to correct it. My statement read.

Quoting Airfoilsguy (Reply 3):
Something probably distracted him

It should have read "Something probably distracted him or her.

Please accept my apology to anyone who might have been offended including said girlfriend.
 boxedin 
It's not a near miss it's a near hit!!
 
flyf15
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Mon Feb 12, 2007 10:30 am

Heres my guess....(I don't have any knowledge of the 747, but if things are done the same way as in the CRJ..)

Handoff to controls to the captain happens for taxiing due to most aircraft only having a tiller on the captain's side. Depending on the captain, they may take controls while still at a good speed on the landing roll or allow the FO to take it much slower. If we're getting off on a highspeed exit, the FO is able to steer with rudder pedals all the way off onto the parallel taxiway.

Commonly, again...depending on the captain, the FO will not stow the reversers if they've done the landing prior to handoff to the captain (at the captain's request) so that the captain can use reverse thrust if desired after they have the controls. I'm guessing here this is what happened. The FO landed the airplane and is in the habit of not stowing the reversers, he then either hands the controls off to the captain who taxies off the runway without realizing the reversers are still out or the FO taxiies off and is not in the habit of doing this and doesn't get them stowed. Although in any of these cases, the reversers should be at, or close to, idle. I don't know if the video is indicitive of idle reverse or not.
 
highflyer9790
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Mon Feb 12, 2007 11:17 am

Quoting ThrottleHold (Reply 5):
Yes, you are wrong!

 banghead 

Quoting Airfoilsguy (Reply 6):
Please accept my apology to anyone who might have been offended including said girlfriend.

apology accepted. (you didnt have much choice  wink  )

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rendezvous
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Mon Feb 12, 2007 3:51 pm

I've seen several aircraft vacate via the high speed taxiway at Auckland with thrust reversers still open. Mind you, we don't have snow..
 
wing
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Mon Feb 12, 2007 7:45 pm

A320 SOP says reverser should be at IDLE at 70 kts-which we have a call out for that-but the reversers can be used until the aircraft comes to safe taxi speed by the decision of the PIC.On contaminated runways delaying to use of brakes with help of as much as possible TRsers can help unwanted skids.Even on the taxiway if you feel that the airplane is faster than you desire you can use your reversers to help reduce the speed,while not heating your brakes.

My opinion on the above video the crew elected to use the TR's until slowing to a safe taxi speed rather than "forgetting"it.
follow me on my facebook page" captain wing's journey log"
 
cftoa
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Wed Feb 14, 2007 6:35 am

Quoting HighFlyer9790 (Thread starter):
The 747 touches down and reversers are deployed as usual, yet instead of being stowed around 60kts they continue through taxiing at taxi speeds. you can see the 747 turn off the runway with reversers still activated around 2:30 mark.

When you activate the reverse thrusters on an aircraft, they must first be unlocked before they are activated. Therefore the pilot could have deactivated them at 60 KIAS, but left them unlocked (open).

However, leaving the reverse thrusters in use under 60 KIAS puts an extreme amount of pressure and strees on the powerplant. You can easily put an engine out of commision by doing this. But at the same time, any pilot would hopefully know not too.

Cheers.
 
Yellowstone
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Wed Feb 14, 2007 6:43 am

Is there any danger that the snow blowing up from the thrust reversers would obscure the pilots' vision and keep them from seeing potential obstructions on the taxiway?
Hydrogen is an odorless, colorless gas which, given enough time, turns into people.
 
highflyer9790
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Wed Feb 14, 2007 6:49 am

Quoting CFTOA (Reply 11):
When you activate the reverse thrusters on an aircraft, they must first be unlocked before they are activated. Therefore the pilot could have deactivated them at 60 KIAS, but left them unlocked (open).

So as far as the actual throttle quadrant, you would first pull out to unlock and then back to activate them?

Quoting Yellowstone (Reply 12):
Is there any danger that the snow blowing up from the thrust reversers would obscure the pilots' vision and keep them from seeing potential obstructions on the taxiway?

from what it looks like, they dont have too much of problem considering they are quite high up on the 747.
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cftoa
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Wed Feb 14, 2007 8:14 am

Quoting HighFlyer9790 (Reply 13):
So as far as the actual throttle quadrant, you would first pull out to unlock and then back to activate them?

Correct. It depends on the type of aircraft, but in general this is the procedure.

Cheers.
 
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jetmech
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Wed Feb 14, 2007 10:44 am

Quoting HighFlyer9790 (Reply 2):
Yea thats why i cant figure out the reason for doing this.



Quoting HighFlyer9790 (Thread starter):
My only thought is that it had something to do with the snow...maybe special winter ops? stuck reversers? (all four engines - doubt it)



Quoting Airfoilsguy (Reply 3):
As for the video the pilot probably didn't push the thrust reverse levers all the way back to their park position. Something probably distracted him.



Quoting HighFlyer9790 (Reply 4):
wouldnt this big of a mistake have led to an immediate sim session and refresher? suspension even? something like that is REALLY hard to be distracted from

Quite often when I see aircraft land on the short runway (07-25) at SYD/YSSY, the pilots will leave the reversers out until they have turned off the runway. I would say that this habit has to do with the short length of 07-25. The pilots leave the reversers out on idle in case the brakes fail at the latter stages of the rollout. They can thus get a quick blast of reverse thrust happeneing much quicker that if they had to wait for the reversers to unlock. Even when using the main runway (16R-34L) at SYD/YSSY, I quite often see the pilots leave out the reversers until they are about to turn off the highspeed exit onto the taxiway, even though the highspeed exits are no where near the end of the runway.

Quoting CFTOA (Reply 11):
However, leaving the reverse thrusters in use under 60 KIAS puts an extreme amount of pressure and strees on the powerplant. You can easily put an engine out of commision by doing this.

It depends. If you leave engines on full reverse at low speed, you may very well cause stalling or surging of the engine, which is bad news.

Quoting Wing (Reply 10):
A320 SOP says reverser should be at IDLE at 70 kts

I believe that this is the key. When aircraft land on the short runway at SYD/YSSY, full reverse will be used until a speed of say 60-70kts, or until the flight crew are reasonbly certain that the plane will stop in the remaining runway length. The reversers are then left in idle until the aircraft has exited the runway. Once on the ground, I would say that ground idle power is available. A jet engine can safely be run in idle reverse at low or zero forward speed with a much reduced chance of surging / stalling or FOD.

Regards, JetMech
JetMech split the back of his pants. He can feel the wind in his hair :shock: .
 
highflyer9790
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Wed Feb 14, 2007 11:10 am

Quoting CFTOA (Reply 14):
It depends on the type of aircraft, but in general this is the procedure.

what about on the airbus A32X which has no reverse throttles, just a "push down" type throttle? how would you know when you have entered the reverse and not just the unlock?
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cftoa
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Wed Feb 14, 2007 12:05 pm

Quoting HighFlyer9790 (Reply 16):
what about on the airbus A32X which has no reverse throttles, just a "push down" type throttle? how would you know when you have entered the reverse and not just the unlock?

In the A32X's case, there is a reverse idle. Therefore, It will automatically unlock and engage when the quadrant is pulled back all the way, but there is an idle mode where the reversers stay unlocked.

http://www.meriweather.com/320/ped/throttle.html#

If you check out that link, and click the text labeling next to the throttle, you will see that there is a range.
starting from the bottom up is the Full Reverse, REV idle, A/THR Range (autothrottle depending on FD or MCP mode)
and then of course TOGA. When you enter a different throttle range, it is displayed on the top left of the primary EICAS screen so that you know what range you are in. There is also audible warning noises when you enter a new range.

I hope that this helped.

Cheers.
 
highflyer9790
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Thu Feb 15, 2007 8:08 am

Quoting CFTOA (Reply 17):
CFTOA

how come the throttle quadrant is boeing tan? ive only seen airbuses with gray cockpits...
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flylku
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Thu Feb 15, 2007 10:44 am

Quoting Airfoilsguy (Reply 6):
It should have read "Something probably distracted him or her.

Forget that P.C. junk. Just say "something probably distracted the pilot."

Your girlfriend should have said to you "Yes, you're right 'he' probably was distracted. 'She' would not have been." But she missed the opportunity to get that jab in.
...are we there yet?
 
sovietjet
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Thu Feb 15, 2007 11:22 am

Did somebody say...taxi with reverse?


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Or how about just one reverser open?


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Really I dont think it's a big deal, aircraft taxies in and eventually the reverse is closed. Why does it have to be as soon as it is stopped  Smile?
 
cftoa
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Thu Feb 15, 2007 2:45 pm

Quoting HighFlyer9790 (Reply 18):
how come the throttle quadrant is boeing tan? ive only seen airbuses with gray cockpits...

That is a very good question actually. I picked that shot because the REV range was clearly visable. If you compare it with another picture, they are identical. Apart from the color of course  Big grin

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ThrottleHold
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Thu Feb 15, 2007 9:41 pm

Quoting CFTOA (Reply 17):
In the A32X's case, there is a reverse idle. Therefore, It will automatically unlock and engage when the quadrant is pulled back all the way, but there is an idle mode where the reversers stay unlocked.

No it won't. The reverser levers in front have to be lifted up before the thrust levers will retard below IDLE.

Quoting CFTOA (Reply 17):
When you enter a different throttle range, it is displayed on the top left of the primary EICAS screen so that you know what range you are in.

That is incorrect. The display in the top right (not left) of the EWD (not EICAS, that's Boeing jargon) shows the active FADEC thrust limit at that point in time.

Quoting CFTOA (Reply 17):
There is also audible warning noises when you enter a new range.

There are no audible warnings associated with a change of autothrust mode. You're getting confused with the "Triple Click" warning of a landing capability downgrade or a mode reversion downgrade.



If you're going to post supposed factual info, please do a little research next time.
 
boeingfixer
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Fri Feb 16, 2007 5:13 am

Since there hasn't been any 744 specific answers I'll post this directly from the Flight Crew Training Manual (FCTM).


----------------------------------------------------------------------------------------------------------------------
Maintain reverse thrust as required, up to maximum, until the airspeed approaches
60 knots. At this point start reducing the reverse thrust so that the reverse thrust
levers are moving down at a rate commensurate with the deceleration rate of the
airplane. The thrust levers should be positioned to reverse idle by taxi speed, then
to full down after the engines have decelerated to idle. The PM should call out 60
knots to assist the PF in scheduling the reverse thrust. The PM should also call out
any inadvertent selection of forward thrust as reverse thrust is cancelled. If an
engine surges during reverse thrust operation, quickly select reverse idle on all
engines.
-----------------------------------------------------------------------------------------------------------------------

Looking at the video, it appears that they exited the runway at a speed higher than normal taxi speed and are still waiting for the engines to reduce to idle thrust. Without seeing when the reversers were actually stowed, one cannot easily determine what was happening on the flight deck and come to a positive conclusion. Personally I think that all is well according the normal 744 operations.

Cheers,

John
Cheers, John YYC
 
wing
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Mon Feb 19, 2007 5:08 am

CFTOA,

Your information about the A320 family is very inaccurate.I strongly suggest you to research(or learn from the knowledgeable) before posting here.

And a notice to the moderators;

If you want this "tech-ops" forums really place to exchange information,you should show some respect to the people who are spending their valuable rest time to share their knowledge and experience with the aviation enthusiasts.In the past this forum was filled with very valuable members and because of very wrong attitudes of especially some moderators,the real pro's are down to handfull.Unfortunately this condition is still continues,I am warning you that if you keep doing this, you will only find 13 year old children with wild imaginations to post in this forum.I don't think any of you have right to do this,this is really unfair against the real enthusiasts.
follow me on my facebook page" captain wing's journey log"
 
Jetfixr757
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Mon Feb 19, 2007 11:06 am

He may have done this because of icy taxi ways to be able to taxi even slower that normal.
Jet
 
boeingfixer
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RE: 747 Reverse Thrust Doesn't Stop (Video)

Mon Feb 19, 2007 11:18 am

Quoting Jetfixr757 (Reply 25):
He may have done this because of icy taxi ways to be able to taxi even slower that normal.
Jet

That's not allowed per SOP's. The thrust reversers must be stowed at taxi speeds. See my above reply(# 23) which explains the procedure.

BTW, if it's that icy, then ops would have shut the airport down to clear the problem and that's what brakes are used for at taxi speeds, not TR's. As a maintainer, If I saw the crew use TR's out of the flight manual restriction area, I would let the crew know my displeasure.

Cheers,

John
Cheers, John YYC

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