qslinger
Posts: 230
Joined: Fri Apr 07, 2006 5:14 pm

Preflight Check: Thrust Reversers

Thu Sep 03, 2009 1:50 am

Hi,

During preflight checks, the captain checks all the control surfaces like the rudder, flaps, ailerons, speed brakes etc but why are the thrust reversers not checked?

I understand that most of the braking comes from the brakes in the MLG and some of it from thrust reversers and the speed brake. But the speed brake is checked before takeoff but the thrust reverser is not. Why is that?
Raj Koona
 
JETPILOT
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RE: Preflight Check: Thrust Reversers

Thu Sep 03, 2009 2:24 am

The reversers shouldn't be used below 60kts to prevent FOD ingestion.
 
BigSaabowski
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RE: Preflight Check: Thrust Reversers

Thu Sep 03, 2009 2:24 am

Speed brakes and flaps are not specifically checked on the aircraft that I'm familiar with. The FO (sometimes the captain) does a primary flight control check and that's when you may see the spoilers automatically deploy on the "wing-down" side. The full travel of the flaps is not checked either, they're simply moved to the takeoff setting. I guess the reversers are not considered a critical-enough item to warrant an individual check. There's not enough time to check everything.
 
pilotpip
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RE: Preflight Check: Thrust Reversers

Thu Sep 03, 2009 2:51 am

Thrust reversers are not required and in fact one or more can be deferred. Jetpilot already mentioned the FOD issue. Cascade reversers are most effective at higher speeds. My only experience is in the Embraer 170 and after 80 kts, the only noticeable difference between 120kts and 80kts is the noise. We're not supposed to use more than idle thrust below 80 and it's only allowed in emergency situations below 60. If one of the reversers are deferred and "pinned" shut, you won't get more than idle out of the other one anyway.

Flaps usually aren't "checked", they're set to the T/O position and left there. I don't know of anybody that checks the speed brake either. What you are seeing is roll spoilers, or Multifunction spoilers which serve as roll spoilers and speed brakes/lift dump spoilers.

At both airlines I've worked at, the F/O performs the control check as part of their before taxi or taxi flow.
DMI
 
DashTrash
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RE: Preflight Check: Thrust Reversers

Thu Sep 03, 2009 3:06 am

We check them in a lot of bizjets. All the Citations require a check on the first flight of the day, and any flight where the landing numbers are predicated on operative reversers.
 
474218
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RE: Preflight Check: Thrust Reversers

Thu Sep 03, 2009 3:19 am

The thrust reversers are checked prior to takeoff: That test comes during the previous landing. If the thrust reversers failed to function on the previous landing they would be written up and repaired or locked out, prior to further dispatch.
 
KELPkid
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RE: Preflight Check: Thrust Reversers

Thu Sep 03, 2009 4:01 am



Quoting DashTrash (Reply 4):
We check them in a lot of bizjets. All the Citations require a check on the first flight of the day, and any flight where the landing numbers are predicated on operative reversers.

From my lineboy days, I remember a few flight crews on bizjets actually popping the reversers open and checking things out as part of their preflight (usually the clamshell type...). I always wondered how you did that without the engines started  Wink
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
 
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HAWK21M
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RE: Preflight Check: Thrust Reversers

Thu Sep 03, 2009 8:51 am



Quoting Qslinger (Thread starter):
why are the thrust reversers not checked

Maintence does it in the check requiring it prior.....any malfunction to the TR can be highlighted by a visual warning in the flight deck.
Although moving the thrust levers with Engines shut down ensures the T/r interconnect is not obstructed.
regds
MEL.
I may not win often, but I damn well never lose!!! ;)
 
DashTrash
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RE: Preflight Check: Thrust Reversers

Thu Sep 03, 2009 3:12 pm



Quoting KELPkid (Reply 6):
From my lineboy days, I remember a few flight crews on bizjets actually popping the reversers open and checking things out as part of their preflight (usually the clamshell type...). I always wondered how you did that without the engines started

Dunno.

Our test is on the taxi checks. We pop them using normal means, then stow them via the emer. stow switches. They're hydraulic, so we have to have engines running to get them open I don't think the aux pump has enough muscle to get them open, and it only runs one system anyway.
 
swiftski
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Joined: Tue Dec 19, 2006 6:19 am

RE: Preflight Check: Thrust Reversers

Thu Sep 03, 2009 4:19 pm

Don't know the rules elsewhere, but a/c are meant to be able to stop completely using brakes alone - reverse thrusters just make things easier and do not in all cases have to be operational to dispatch.
 
474218
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Joined: Mon Oct 10, 2005 12:27 pm

RE: Preflight Check: Thrust Reversers

Thu Sep 03, 2009 4:31 pm



Quoting Swiftski (Reply 9):
Don't know the rules elsewhere, but a/c are meant to be able to stop completely using brakes alone - reverse thrusters just make things easier and do not in all cases have to be operational to dispatch.

They don't have to be operational for dispatch, but if they inoperable it must be noted, so the crew knows and can plan their landing correctly.
 
Tristarsteve
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Joined: Tue Nov 22, 2005 11:04 pm

RE: Preflight Check: Thrust Reversers

Thu Sep 03, 2009 4:33 pm

On the RB211 the reversers are checked stowed and locked on the preflight check. They must not be operated before takeoff.
 
swiftski
Posts: 1837
Joined: Tue Dec 19, 2006 6:19 am

RE: Preflight Check: Thrust Reversers

Thu Sep 03, 2009 4:33 pm



Quoting 474218 (Reply 10):
They don't have to be operational for dispatch, but if they inoperable it must be noted, so the crew knows and can plan their landing correctly.

Agreed.
 
DashTrash
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RE: Preflight Check: Thrust Reversers

Thu Sep 03, 2009 5:36 pm

What are reverse thrusters? Big grin
 
KELPkid
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Joined: Wed Nov 02, 2005 5:33 am

RE: Preflight Check: Thrust Reversers

Thu Sep 03, 2009 9:15 pm



Quoting DashTrash (Reply 13):
What are reverse thrusters?

http://en.wikipedia.org/wiki/Ullage_motor  bigthumbsup 
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
 
DashTrash
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Joined: Mon Aug 21, 2006 8:44 am

RE: Preflight Check: Thrust Reversers

Fri Sep 04, 2009 1:25 am



Quoting KELPkid (Reply 14):
http://en.wikipedia.org/wiki/Ullage_motor bigthumbsup

Didn't know they were called that!  Big grin
 
jetstar
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RE: Preflight Check: Thrust Reversers

Fri Sep 04, 2009 2:15 am

On the 4 engine Lockheed JetStar bizjet, we would check the thrust reversers by extending them during taxi, we would only do this the first flight of the day. A lot of times to save fuel we would taxi out on 2 engines and when we reached the check reversers part of the taxi check list, we would hold off continuing the check list until we started the remaining 2 engines and tested the reversers.

We could extend all the reversers with only # 2 engine running because #2 engine powered the #1 hydraulic system, which supplied hydraulic power to all the reversers. But part of the test was to see engine rpm increase when the reversers were extended so we waited until all the engines were running.

On the ground, we used the electric hydraulic pump to power the #1 hydraulic system so we could extend and retract the reversers as needed. Part of the preflight was to bleed all the hydraulic pressure off, including all the accumulators, both the brake and reverser accumulators held pressure because they were designed to operate the systems in case of a hydraulic failure, so the only way to bleed pressure off was to operate the brakes and reversers. We could get about 5 brake applications and extend, retract and partially extend all 4 reversers just on full accumulator pressure.

On the JetStar some operators on a windy day would extend the reversers while the aircraft was parked to prevent the wind from blowing up the tailpipe. If I remember correctly there was a 30 knot wind restriction when starting the engines with the wind blowing up the tailpipe, it was an approved procedure to start the engines in this wind condition with the reverser extended and retract the reverser once the engine reached idle.

JetStar
 
DeltaGuy
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Joined: Wed Sep 12, 2001 5:25 am

RE: Preflight Check: Thrust Reversers

Mon Sep 07, 2009 2:38 am



Quoting DashTrash (Reply 4):
We check them in a lot of bizjets.

Dash is right, most business aircraft check them. I've seen most Citations running them on taxi out.

On the Gulfstream it's a first flight of the day item, either check them both at the same time or one at a time. In fact it's an AFM limitation, once every 100 hours or 100 flights, whichever comes first (though you use them all the time). Sometimes taxi speed gets high, poping a reverser will help to slow you down a bit..just idle reverse though.

DeltaGuy
"The cockpit, what is it?" "It's the little room in the front of the plane where the pilot sits, but that's not importan
 
josekmlb
Posts: 195
Joined: Thu May 29, 2008 7:34 am

RE: Preflight Check: Thrust Reversers

Thu Sep 10, 2009 11:33 pm

About a week ago I serviced a DC-9 for the U.S. Marines and they had the reverser's deployed on the ramp and they said they leave it like that for RON's. I just thought that was kind of weired pulling up to see them deployed.
 
boeing767mech
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Joined: Fri Dec 15, 2000 5:03 pm

RE: Preflight Check: Thrust Reversers

Fri Sep 11, 2009 11:47 am

According to a mechanic I used to work with, he said the USAF would deploy the reversers on the C-5 while taxi out to the runway to check and clear the water out of the cascade vanes. This was common practice until it was known to be a cause of a C-5 sn#68-0228 to crash after take-off in Ramstein Air Base Germany.

http://rustyknight98.com/C5/C5.htm
http://aviation-safety.net/database/record.php?id=19900829-0

David
Never under-estimate the predictably of stupidty

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