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rootsair
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Reverse Thrust Before Landing:dangerous?

Sat Feb 03, 2007 7:21 pm

Hi fellow a.netters,

I came up with a really nice picture of Air Koryo IL-62 with reverse thrust deployed before even landing !

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Photo © Raymond Wang


I have seen the same on a Cubana IL-62

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Photo © José Geraldes


I was wondering , is this dangerous or not? Have you ever seen that before?
I wonder if its a common feature of IL-62's

Regards
BM
 
Tristarsteve
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RE: Reverse Thrust Before Landing:dangerous?

Sat Feb 03, 2007 8:13 pm

Dunno but on the HS Trident we always used to descend with the engines in reverse. It was the only way to slow it down. Had them in fwd thrust for landing though!
 
MD11Engineer
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RE: Reverse Thrust Before Landing:dangerous?

Sat Feb 03, 2007 8:22 pm

Standard procedure on IL-62.

Jan
 
BrianDromey
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RE: Reverse Thrust Before Landing:dangerous?

Sat Feb 03, 2007 8:40 pm

Hi all,

I think that it depends on the aircraft type. Seems to be more common with "T-Tail" aircraft.

Lauda Air lost a 767 when the thrust reverser deployed at cruise height. I dont remember all the science, but I think the disturbed airflow over the wing makes it much harder to control the aircraft than on an aircraft with rear mounted engines and a T-tail.

Cheers,
Brian.
 
highpeaklad
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RE: Reverse Thrust Before Landing:dangerous?

Sat Feb 03, 2007 8:41 pm

Quoting TristarSteve (Reply 1):
Dunno but on the HS Trident we always used to descend with the engines in reverse. It was the only way to slow it down. Had them in fwd thrust for landing though!

It was on a discovery wings programme, the old pilot said they could get descent rates of 10000 fpm using it.

Chris
 
dougbr2006
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RE: Reverse Thrust Before Landing:dangerous?

Sat Feb 03, 2007 9:04 pm

Strange, I always thought that thrust reversers were inhibited by weight on wheels switches especially on large fanned engines.
 
PlymSpotter
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RE: Reverse Thrust Before Landing:dangerous?

Sat Feb 03, 2007 10:07 pm

It was used by accident last week when I was landing at DAM in a Yak40. The aircraft was still several meters in the air and as the reverse went on the nose pitched up to about 15/20 degrees and we pitched a little sideways before contacting the runway heavily with main gear. Nose was still high and came down very heavily, really shook everything in the cabin and several seats fell over, things were thrown about as it went from side to side down the runway - really thought we were going off.

Another interesting experience of historic airliners!


Dan Smile
 
connies4ever
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RE: Reverse Thrust Before Landing:dangerous?

Sat Feb 03, 2007 10:10 pm

Several times on AC flights in the 60's reverse was used for rapid descent on the DC-8-40s. I can't recall it on the -50s with PW engines, but definitely with the RR Conways. As I recall it, only the inboard engines went into reverse.
 
FlySSC
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RE: Reverse Thrust Before Landing:dangerous?

Sat Feb 03, 2007 10:13 pm

Already discussed :
https://www.airliners.net/discussions...eneral_aviation/read.main/2456602/



Pilots know what they do ! I guess that if they use thrust reversers on those aircraft (IL62), it is simply because it's a standard and logical procedure.

Note that Pilots on Concorde were used to use regularly the thrust reversers in flight to slow down the plane during the descent.
That was also a standard and normal procedure.

Some aircraft are able to safely use reverse thrust in flight, though the majority of these are propeller-driven. In-flight use of reverse thrust has several advantages: It allows for rapid deceleration, enabling quick changes of speed; It also prevents the speed buildup normally associated with steep dives, allowing for rapid loss of altitude, which can be especially useful in hostile environments such as combat zones, and when making steep approaches to land.

For example, the ATR 72 turboprop can reverse thrust in flight, should the appropriate control lock be withdrawn. The Hawker-Siddeley HS121 Trident was capable of descending at up to 10,000 ft/min (3,048 m/min) by use of the thrust reversers, though this capability was rarely used. The US Air Force's C-17A is one of the only modern aircraft that uses reverse thrust in flight. The Boeing-manufactured aircraft is capable of in-flight deployment of reverse thrust on all four engines to facilitate steep tactical descents up to 15,000 ft/min (4,600 m/min) into combat environments.


[Edited 2007-02-03 14:18:48]

[Edited 2007-02-03 14:23:20]
 
Magyarorszag
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RE: Reverse Thrust Before Landing:dangerous?

Sun Feb 04, 2007 1:20 am

Quoting Connies4ever (Reply 7):
Several times on AC flights in the 60's reverse was used for rapid descent on the DC-8-40s. I can't recall it on the -50s with PW engines, but definitely with the RR Conways. As I recall it, only the inboard engines went into reverse.

I remember having read something like that in Airways with a DC-8-63 which carried the journalist while the US President was on tour. Seemed really amazing. The DC-8 had to take off after Air Force One and land before it at the following airport with some rather wild approaches.

Cheers.
 
ReidYYZ
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RE: Reverse Thrust Before Landing:dangerous?

Sun Feb 04, 2007 4:06 pm

DC8's were designed with the two inboard engines allowed to go in reverse. I can't remember if they even had spoilers. The IL-62's above are designed and equipped as well. It is not a 'T' tail specific thing. The Laudair accident was uncommanded deployment of the reverser. This, I believe, lead to the requirement to retrofit existing reversers and put into the design of new reverser systems a tertiary lock.
 
cedarjet
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RE: Reverse Thrust Before Landing:dangerous?

Mon Feb 05, 2007 12:27 am

Quoting PlymSpotter (Reply 6):
It was used by accident last week when I was landing at DAM in a Yak40.

Dude have you been to Iran yet? Saha? TRIP REPORT?!

Quoting Magyarorszag (Reply 9):
I remember having read something like that in Airways with a DC-8-63 which carried the journalist while the US President was on tour. Seemed really amazing. The DC-8 had to take off after Air Force One and land before it at the following airport with some rather wild approaches.

I remember reading that too. All the journos were pretty scared, and drinks were spilled. Great fun.
 
MissedApproach
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RE: Reverse Thrust Before Landing:dangerous?

Mon Feb 05, 2007 1:19 am

Quoting ReidYYZ (Reply 10):
I can't remember if they even had spoilers.

They did. Use of the spoilers in flight was not approved, hence the inflight use of thrust reversers. Accidental spoiler deployment led to the crash of AC Flight 621 DC-8-63 in 1970.
 
Mir
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RE: Reverse Thrust Before Landing:dangerous?

Mon Feb 05, 2007 4:38 am

The NASA Shuttle Training Aircraft is a Gulfstream that is modified to deploy its thrust reversers inflight in order to simulate the gliding (i.e. falling) characteristics of the orbiter.

-Mir
 
aogdesk
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RE: Reverse Thrust Before Landing:dangerous?

Mon Feb 05, 2007 5:00 am

AFAIK, #2 engine on DC10-MD-11 could be put in reverse before landing (at a certain radio altitude I think)
 
sovietjet
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RE: Reverse Thrust Before Landing:dangerous?

Mon Feb 05, 2007 5:31 am

Quoting PlymSpotter (Reply 6):
It was used by accident last week when I was landing at DAM in a Yak40. The aircraft was still several meters in the air and as the reverse went on the nose pitched up to about 15/20 degrees and we pitched a little sideways before contacting the runway heavily with main gear. Nose was still high and came down very heavily, really shook everything in the cabin and several seats fell over, things were thrown about as it went from side to side down the runway - really thought we were going off.

Another interesting experience of historic airliners!


Dan

Actually in Yak-40 it's pretty standard as well...and even more safe because only the center engine has reverse. Either way Tu-154 and especially Il-62 do it all the time.


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Photo © Petr Garaj



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Photo © Andreas Heilmann



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Photo © Howard Chaloner

 
arluna
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RE: Reverse Thrust Before Landing:dangerous?

Mon Feb 05, 2007 5:49 am

Quoting Connies4ever (Reply 7):
As I recall it, only the inboard engines went into reverse.

I was a pax on a DC-8 in 1970 on my way to Viet Nam and the pilot announced over the PA that ATC had kept us high for too long and he was going to use the inboard TR's to get us down quickly. It worked! It was very noisy but we came down to pattern altitude very quickly.

The engines on the -8 were Conways and the A/C was a -60 and we were landing at Yokota AB in Japan.

J

[Edited 2007-02-04 21:56:08]
 
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HAWK21M
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RE: Reverse Thrust Before Landing:dangerous?

Mon Feb 05, 2007 5:55 pm

Quoting MD11Engineer (Reply 2):
Standard procedure on IL-62.

Any Reason for its Inclusion in the SOP.Is there a min Altitude reccommended.
regds
MEL
 
sovietjet
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RE: Reverse Thrust Before Landing:dangerous?

Mon Feb 05, 2007 6:10 pm

Some older Soviet airfields at the time might have had pretty short runways. I don't know if there is a min altitude or if it is just done "right before touchdown".
 
boeingfixer
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RE: Reverse Thrust Before Landing:dangerous?

Tue Feb 06, 2007 12:07 am

Quoting Aogdesk (Reply 14):
AFAIK, #2 engine on DC10-MD-11 could be put in reverse before landing (at a certain radio altitude I think)

The thrust reversers on the DC-10/MD-11 are for ground use only. The system is armed at a RA of 7' or wheel spin-up greater than 80 knots. There are several other interlock features before you can apply reverse thrust on the MD-11 as well.

Cheers,

John
 
TimT
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RE: Reverse Thrust Before Landing:dangerous?

Tue Feb 06, 2007 1:28 am

DC-10 has to see nose landing gear on the ground (strut compressed) before #2 will unlock. Keeps the nose from slamming down.
 
MD11Fanatic
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RE: Reverse Thrust Before Landing:dangerous?

Tue Feb 06, 2007 2:07 am

Here is a video of a C-17 doing a combat descent with the thrust reversers out, very violent isn't it!


http://www.flightlevel350.com/Aircra..._Untitled_Aviation_Video-5025.html
 
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Starlionblue
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RE: Reverse Thrust Before Landing:dangerous?

Tue Feb 06, 2007 2:32 am

Quoting BrianDromey (Reply 3):
Lauda Air lost a 767 when the thrust reverser deployed at cruise height. I dont remember all the science, but I think the disturbed airflow over the wing makes it much harder to control the aircraft than on an aircraft with rear mounted engines and a T-tail.

The issue there was also asymmetrical thrust since only one engine went into reverse. With both in reverse, the situation would have been quite different. Needless to say, the system has been changed since then.

Quoting Dougbr2006 (Reply 5):
Strange, I always thought that thrust reversers were inhibited by weight on wheels switches especially on large fanned engines.

As said above, it very much depends on aircraft type.


I seem to recall Captain Squares (or was it B747Skipper?) saying that you can in fact reverse in flight on the 747. The procedure is reserved for emergencies such as depressurization when you need to get down very fast from cruise. You can point the nose down and use the reversers to keep the speed under "never exceed".

He also pointed out the whole plane shakes like a "#¤"!#¤#"¤ so it's a sure fire way to induce brown trouser moments in the pax.
 
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LHRBFSTrident
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RE: Reverse Thrust Before Landing:dangerous?

Tue Feb 06, 2007 5:19 am

Quoting MissedApproach (Reply 12):
Accidental spoiler deployment led to the crash of AC Flight 621 DC-8-63 in 1970.

IIRC there was an SK incident at Trondheim in the late 80's where one of their DC-9 20s or 40s dropped onto the runway from approx 10 metres high as either the reversers or the spoilers were deployed too early (can't remember which)

The a/c hit the ground so hard there was wing spar damage and the L engine became partially detached from the fuselage

The a/c went around, and landed safely the second time - I believe the consensus was 'how did it stay aloft for the go-around?'

Flight International carried photos of the engine hanging at a very unusual angle from it's normal position. Believe the rego was SE-DAT...
 
2H4
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RE: Reverse Thrust Before Landing:dangerous?

Tue Feb 06, 2007 5:25 am




Quoting TimT (Reply 20):
DC-10 has to see nose landing gear on the ground (strut compressed) before #2 will unlock. Keeps the nose from slamming down.

Wouldn't the reverse thrust from #2 produce a nose-up moment?


2H4


 
MDorBust
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RE: Reverse Thrust Before Landing:dangerous?

Tue Feb 06, 2007 7:51 am

Quoting FlySSC (Reply 8):
The US Air Force's C-17A is one of the only modern aircraft that uses reverse thrust in flight.

I remember seeing somewhere a video of a C-5 using the TR's on the inboards while doing a breakaway from a tanker.

The video was taken from the POV of what I think was a KC-10.
 
TimT
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RE: Reverse Thrust Before Landing:dangerous?

Tue Feb 06, 2007 10:04 am

2H4

You would think so, but it does not. #2 reverse is not all that effective. They had to put so many different cascades in #2 to keep the reverse thrust from damaging rudder, pylon, elevator and horizontal stab, the thing is just not all that good.

And you have to hold the nose up on landing, then let it down.
 
3DPlanes
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RE: Reverse Thrust Before Landing:dangerous?

Tue Feb 06, 2007 12:28 pm

So on the Yaks and ILs, how early do they deploy the TRs?

In that last shot above, he looks to be a good ways up... May be the angle though.

And the wings aren't level, suggesting maybe a crosswind, which begs the question - if it was gusty and they had to abort the landing, are there any bad effects? Seems like it would delay getting to TOGA power...
 
MD11Fanatic
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RE: Reverse Thrust Before Landing:dangerous?

Tue Feb 06, 2007 12:36 pm

Quoting TimT (Reply 26):

I have a friend who is Omni Air DC-10 captain. He said every so often they have big issues with #2 reverse not stowing, and whenever they land "off base" or somewhere without adequate maintenance facilities (IE Middle East troop run for US military) they often times do not even deploy the #2 reverser for fear of not being able to take off again due to it not stowing.
 
speedracer1407
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RE: Reverse Thrust Before Landing:dangerous?

Tue Feb 06, 2007 1:46 pm

Quoting 2H4 (Reply 24):

Wouldn't the reverse thrust from #2 produce a nose-up moment?

I wouldn't know one way or the other, but perhaps R/T on the #2 blanks out airflow over the horizontal stab. The nacell sits pretty much on top of the H stab, but the cascades are a wee bit behind. I donno, maybe it's enough turbulent semi-foreward facing thrust to reduce the H-stab's effectiveness, and cause a bit of nose-down at the lowish speeds of touchdown.

Quoting 3DPlanes (Reply 27):
And the wings aren't level, suggesting maybe a crosswind, which begs the question - if it was gusty and they had to abort the landing, are there any bad effects? Seems like it would delay getting to TOGA power...

Again, I wouldn't know, but watching those bucket-type reversers on DC-9 series A/C, they deploy and retract very quickly, seems like less than a second.
 
SFOMB67
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RE: Reverse Thrust Before Landing:dangerous?

Tue Feb 06, 2007 2:47 pm

Quoting MissedApproach (Reply 12):
They did. Use of the spoilers in flight was not approved, hence the inflight use of thrust reversers. Accidental spoiler deployment led to the crash of AC Flight 621 DC-8-63 in 1970.

As far as I know, all DC-8's (-71 &73 included) used their inboard T/R's, inflight, to slow the acft down. Otbd spoilers worked with the ailerons, inflight, but only when the main ldg gear was down. Ground spoilers deployed with nose gear touchdown (also req'd antiskid spinup on Mark III landing gear).
 
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SuseJ772
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RE: Reverse Thrust Before Landing:dangerous?

Wed Feb 07, 2007 4:44 am

Quoting Starlionblue (Reply 22):
I seem to recall Captain Squares (or was it B747Skipper?) saying that you can in fact reverse in flight on the 747. The procedure is reserved for emergencies such as depressurization when you need to get down very fast from cruise. You can point the nose down and use the reversers to keep the speed under "never exceed".

He also pointed out the whole plane shakes like a "#¤"!#¤#"¤ so it's a sure fire way to induce brown trouser moments in the pax.

That would be an amazing thing to experience.
 
boeingfixer
Posts: 573
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RE: Reverse Thrust Before Landing:dangerous?

Thu Feb 08, 2007 7:04 am

Quoting Starlionblue (Reply 22):
I seem to recall Captain Squares (or was it B747Skipper?) saying that you can in fact reverse in flight on the 747. The procedure is reserved for emergencies such as depressurization when you need to get down very fast from cruise. You can point the nose down and use the reversers to keep the speed under "never exceed".

He also pointed out the whole plane shakes like a "#¤"!#¤#"¤ so it's a sure fire way to induce brown trouser moments in the pax.

Can't be done on a 747. Each MLG(Main Landing Gear) truck has a tilt sensor for AIR/GROUND sensing to ensure that the reversers only operate on the ground. The 747 QRH for emergency descent only has the throttles placed to idle as the TR's would not deploy even if you tried to.

Cheers,

John
 
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Starlionblue
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RE: Reverse Thrust Before Landing:dangerous?

Thu Feb 08, 2007 11:51 am

Quoting BoeingFixer (Reply 32):

Can't be done on a 747. Each MLG(Main Landing Gear) truck has a tilt sensor for AIR/GROUND sensing to ensure that the reversers only operate on the ground. The 747 QRH for emergency descent only has the throttles placed to idle as the TR's would not deploy even if you tried to.

Good to know ty.

A
 
arluna
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RE: Reverse Thrust Before Landing:dangerous?

Sun Feb 11, 2007 12:33 pm

Quoting Arluna (Reply 16):
The engines on the -8 were Conways and the A/C was a -60

Hello all,

After some research I think I may have made an error in relying on my memories from thirty-seven years ago. It seems that there were no -60's built with Conways, only JT3D's!!

The fact remains that the pilot used TR's on the inboards and we came down fast!!!!!!

Sorry about that.

J
 
TrijetsRMissed
Posts: 1983
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RE: Reverse Thrust Before Landing:dangerous?

Sun Feb 11, 2007 3:31 pm

Quoting BrianDromey (Reply 3):
Lauda Air lost a 767 when the thrust reverser deployed at cruise height. I dont remember all the science, but I think the disturbed airflow over the wing makes it much harder to control the aircraft than on an aircraft with rear mounted engines and a T-tail.

Uncommanded thrust reverser deployment at cruise height and speed is virtually certain death. In the Lauda Air disaster, it was determined that recovery was not possible three seconds after the deployment. The same applies to T-tailed aircraft. A TAM F100 had a similar accident, although the deployment occurred during climb, not cruise.

Quoting Starlionblue (Reply 22):
The issue there was also asymmetrical thrust since only one engine went into reverse. With both in reverse, the situation would have been quite different. Needless to say, the system has been changed since then.

The plane would have crashed regardless. While the thrust reverser deployment was uncommanded, the pilots could not reinforce forward thrust in the engine. The sudden change in propulsion caused an excessive role and nose dive that tore the plane apart before it even hit the ground.
 
n8076u
Posts: 419
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RE: Reverse Thrust Before Landing:dangerous?

Sun Feb 11, 2007 6:52 pm

Quoting Sfomb67 (Reply 30):
As far as I know, all DC-8's (-71 &73 included) used their inboard T/R's, inflight, to slow the acft down.

You're right, all DC-8s, series 10 thru 70 could use their inboard thrust reversers in flight. Some DC-8s could also use the outboard engine thrust reversers in flight as well. For anyone that's interested, here's some info I dug out from the "limitations" section of an older UA DC-8 manual, an even older Douglas flight manual and a Kalitta operations manual:

-Maximum speed for extending thrust brakes - 390 kts. or M = .88

-Thrust reversers must not be used in flight below a speed of 200 knots (Kalitta manual states 190 knots).

-Wing flaps must be completely retracted for all inflight thrust brake operations.


---Maximum thrust usable during thrust brake operation is as follows:

-Engines #1 and #4:

-thrust brake stop limit for JT3C engines (DC-8-10) - idle reverse.

-thrust brake stop limit for JT4A engines (used on DC-8-20 and DC-8-30) - Approx. 31% max continuous.

-on JT3D powered airplanes N8044U-N8055U (some DC-8-50) and N8066U-N8099U (again, some -50 series and all of the -61 series) power settings up to idle reverse available with gear extended.

-on all other JT3D (and all CFM56) powered airplanes, mechanical stop prevents inflight use (some -50 series and ALL -62 series, and also is the case with the -63 and with all -70 series).


--Engines #2 and #3:

-maximum continuous thrust for JT3C engines (series -10)
-maximum continuous thrust for JT4A engines (series -20 and -30)
-maximum continuous thrust for JT3D engines (series -50 thru -60)
-maximum continuous thrust for CFM56 engines (series -70)
-Sorry, no specific info for the -40 series.

Confusing, eh?  Wink

Chris
 
PlymSpotter
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RE: Reverse Thrust Before Landing:dangerous?

Sun Feb 11, 2007 7:07 pm

Quoting Cedarjet (Reply 11):
Dude have you been to Iran yet? Saha? TRIP REPORT?!

I've not been to Iran, had some difficulties with that, but I have been around Syria on various oldies which was great ... trip report is in progress but I don't have access to any pictures as I'm in one place and my card reader and processing software is in another, soon though Wink

Quoting Sovietjet (Reply 15):
Actually in Yak-40 it's pretty standard as well...and even more safe because only the center engine has reverse. Either way Tu-154 and especially Il-62 do it all the time.

Ah that is interesting, it certainly didn't feel very much in control to me! I also wondered what the rush was, we had the whole of DAM's runway ahead of us to roll out along and the Yak-40 is hardly a large aircraft.

Dan Smile
 
britjap
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RE: Reverse Thrust Before Landing:dangerous?

Sun Feb 11, 2007 8:41 pm

During approach the engines will generally be idling. Once thrust reversers are set, the engines take several seconds to spool up. Pilots used to open the thrust reversers a bit early at a point such that they would just be becoming effective at the point of touchdown, thus saving the wasted seconds waiting for them to spool up once you are already on the runway.

As mentioned by others however the Lauda Air accident changed all that. To prevent in flight thrust reverser deployment, aircraft are now fitted with WOW, Weight-On-Wheels, sensors that will not allow their deployment until the a/c is on the ground.

I think that this has nothing to do with a/c type. I was under the impression that this is now an FAA/EASA regulation to have these sensors fitted.

However the photo you gave clearly shows thrust reverser deployment before touchdown, on an aircraft in EASA governed airspace.

So I am puzzled.  Confused
 
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HAWK21M
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RE: Reverse Thrust Before Landing:dangerous?

Mon Feb 12, 2007 10:14 pm

Quoting Britjap (Reply 38):
As mentioned by others however the Lauda Air accident changed all that. To prevent in flight thrust reverser deployment, aircraft are now fitted with WOW, Weight-On-Wheels, sensors that will not allow their deployment until the a/c is on the ground

In Addition to the MLG Air-Grd sense the NLG sense is needed too.
regds
MEL
 
cftoa
Posts: 126
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RE: Reverse Thrust Before Landing:dangerous?

Wed Feb 14, 2007 8:18 am

As far as I know, you really aren't supposed to do it unless your rear struts have touched the ground. Although, I have seen T-Tails do this before during crosswind or similar situation.

Cheers.

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