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Use Of Thrust Reversers During Descent  
User currently offlineTg 747-300 From Norway, joined Nov 1999, 1318 posts, RR: 0
Posted (12 years 4 months 5 hours ago) and read 6931 times:

I was wondring if aircrafts , mainly DC9 and MD80 , can use the thrust reversers to slow down during descent.

I'm asking since i have an idea of having experienced that on a SK MD80 back in 1999

tg 747-300


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28 replies: All unread, showing first 25:
 
User currently offlineJcxp15 From United States of America, joined Jun 2001, 997 posts, RR: 5
Reply 1, posted (12 years 4 months 5 hours ago) and read 6799 times:

As far as I know it's not possible for planes to use reversers in flight. There is a safety mechanism which prevents this. Wasn't there that theory about Swissair 111 about how the reversers went off, being the cause of the crash? This has obviously changed. From what I know, reversers in flight can be catastrophic.

User currently offlineTg 747-300 From Norway, joined Nov 1999, 1318 posts, RR: 0
Reply 2, posted (12 years 4 months 5 hours ago) and read 6765 times:

I think its the Lauda 767 accident near Bangkok ,Thailand that you are remembering. If I'm not wrong one of the thrust reversers deployed during climb, causing one engine to reverse and the other to push foreward. And wasn't tha crew a litle unsure about whatwas going on?

tg 747-300



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User currently offlineJETPILOT From United States of America, joined May 1999, 3130 posts, RR: 29
Reply 3, posted (12 years 4 months 4 hours ago) and read 6761 times:

DC8 can go into reverse thrust in flight.

Full reverse available on the inboards at all times, and idle thrust avaialable on the outboards with the gear down and locked.

Not sure about the 70 series with the CFM engines though.

JET


User currently offlineBio15 From Colombia, joined Mar 2001, 1089 posts, RR: 7
Reply 4, posted (12 years 4 months 4 hours ago) and read 6732 times:

I believe I have read on this forum previously that the DC8 has the ability to deploy the reversers during flight with some sort of override mechanism. But please confirm that; not 100% on this one.

-bio


User currently offlineBio15 From Colombia, joined Mar 2001, 1089 posts, RR: 7
Reply 5, posted (12 years 4 months 4 hours ago) and read 6712 times:

Yea, there you go, Jet has already resolved it.  Smile

User currently offlineIvo21 From Netherlands, joined Jan 2002, 25 posts, RR: 0
Reply 6, posted (12 years 4 months 4 hours ago) and read 6695 times:

The thrust reverse system can only be used when the antiskid/autobrake system senses a ground mode. The autobrake system can use the reverse thrust if needed for the set deceleration rate. As far as I know the thrust reversers cannot be used in flight.

CU

Ivo


User currently offlineTurbineBeaver From United States of America, joined Jan 2002, 1199 posts, RR: 0
Reply 7, posted (12 years 4 months 3 hours ago) and read 6678 times:

Guys, my memory is vague, BUT...

Isn't this the main plot in...Michael Crichton's(??) novel, Airframe about the Norton 11 or some sort of airplane over the pacific? It's been about 4 years since I read the book, so I can't remember completely.

TB


User currently offlineStarship From South Africa, joined Nov 1999, 1098 posts, RR: 14
Reply 8, posted (12 years 4 months 1 hour ago) and read 6649 times:

The Boeing C-17 Globemaster III has four Pratt & Whitney PW2040 series turbofans equipped with directed-flow thrust reversers capable of deployment in flight.

I think I have something on video somewhere, where they state that with the use of in flight thust reversers, the C-17 can descend at the rate of 16 000 ft/min and then land in as little as 1 400 ft. Mighty impressive and worthy of its 22 world records.



Behind every "no" is a "yes"
User currently offlineHurricane From United States of America, joined Feb 2002, 1443 posts, RR: 1
Reply 9, posted (12 years 4 months ago) and read 6639 times:

Turbine...I thought Airframe's crash was caused by an inflight involuntary slats deployment...

User currently offlineShaun3000 From United States of America, joined Mar 2002, 445 posts, RR: 0
Reply 10, posted (12 years 3 months 4 weeks 1 day 22 hours ago) and read 6606 times:

Yes, Hurricane, _Airframe_ revolved around an inflight slat deployment.

In regards to thrust reversers in flight, I recall reading a thread on this forum a while back where some guy was on a 737-200 that had to make an emergencey decent. He said the pilot had full spoilers and thrust reverse, among other things, to slow the plane during the very rapid decent.

So I suppose it is possible on some planes.


User currently offlineSkyguy11 From , joined Dec 1969, posts, RR:
Reply 11, posted (12 years 3 months 4 weeks 1 day 21 hours ago) and read 6591 times:

There is a modified Gulfstream NASA uses to train their Space Shuttle pilots. They go up really high (I forgot the specifics of it) and deploy spoilers and full reverse thrust to simulate the glide ratio of a Space Shuttle (some glider!).

User currently offlineMiles_mechanic From Canada, joined Sep 2001, 137 posts, RR: 0
Reply 12, posted (12 years 3 months 4 weeks 1 day 19 hours ago) and read 6581 times:

I saw the article on CNN about the shuttle training aircraft, they said that the modified Gulfstream goes up to 40,000 ft., and about 4 miles out and does there approach to the runway with the reverser thrust engaged. They showed the view from inside as they performed the manouver, what a ride that must be. They don't take the reverse thrust off until they are over the runway, but the pilot said they could land with them still deployed. The airplane has special computer controls installed to ensure that both engines are putting out the same thrust in reverse so they don't loose control of the airplane.

Miles


User currently offlineL-188 From United States of America, joined Jul 1999, 29795 posts, RR: 58
Reply 13, posted (12 years 3 months 4 weeks 1 day 18 hours ago) and read 6568 times:

I have seen photos of IL-62s on final that have had the outboard engines reversers deployed.

Probably for the same reason that it is used on the DC-8.



OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.
User currently offlineJetguy From , joined Dec 1969, posts, RR:
Reply 14, posted (12 years 3 months 4 weeks 1 day 15 hours ago) and read 6546 times:

Oh by the way, on the NASA Gulfstream Shuttle trainer, they also extend the main landing gear for additional drag. What a ride that must be - spoilers, main landing gear, and full reverse thrust...
Yee Haw!


User currently offlinePositive rate From Australia, joined Sep 2001, 2143 posts, RR: 1
Reply 15, posted (12 years 3 months 4 weeks 1 day 14 hours ago) and read 6524 times:

Reverse- thrust is available on some a/c types in flight. DC-8/NASA Gulfstream jet and possibly the 747. However it is not possible on a twin engine jet like a 767 because the engines are too far inboard and they would get wrenched off and the plane would break apart(Lauda Air 767-300ER in 1991). There is however a recovery manouver for pilots in case the reversers do inadvertently deploy- about a 3 sec window from reverser deployment to airframe failure for the pilots to take action!

User currently offlineVc10 From United Kingdom, joined Nov 2001, 1408 posts, RR: 16
Reply 16, posted (12 years 3 months 4 weeks 1 day 14 hours ago) and read 6520 times:

In my experience most aircraft whether prop or pure jet have a built in automatic protection system which will prevent the engine going into reverse thrust in the air, or should that happen then the engine power will be reduced to idle power. Now some aircraft have a system which at the pilots command overrides that ptotection system and allows certain engines to go into reverse thrust usually at very low powers while the aircraft is airbourne.
From my own experience an engine inadvertantly going in reverse in flight is not always a disaster as is shown by my own example when flying a VC-10 at 35,000ft when the No 3 engine [and on a Vc-10 that is quite inboard ] decided to go into reverse. The auto protection system immediately reduced the power to idle thrust, and in fact it was all to much for the engine which flamed out. Yes the situation was not very pleasant and not to be repeated by choice , but the aircraft landed on time and I seem to remember it departed only slightly late [ Due reverser being locked out ]
Just for interest the Concorde once it is below Mach 1 and I believe 30,000ft can select it's two inboard engines into reverse thrust at idle power. This is usually done so as to increase the rate of descent, which with idle reverse in will be about 10,000ft per min.

Regards little vc10


User currently offlineStarship From South Africa, joined Nov 1999, 1098 posts, RR: 14
Reply 17, posted (12 years 3 months 4 weeks 1 day 7 hours ago) and read 6473 times:

L-188 is quite correct about the IL-62 deploying thrust reversers in the air. However after scanning through a few hundred pics in the database, I came to the conclusion that the thrust reversers are deployed only seconds before touchdown. The pic I really wanted I haven't found yet, but I'll carry on looking. In the mean time, here are two illustrating deployed TR's in flight.


View Large View Medium
Click here for bigger photo!

Photo © Malc Southern
View Large View Medium
Click here for bigger photo!

Photo © Josep Duran






Behind every "no" is a "yes"
User currently offlineJETPILOT From United States of America, joined May 1999, 3130 posts, RR: 29
Reply 18, posted (12 years 3 months 4 weeks 1 day 3 hours ago) and read 6440 times:

Thats crazy !!!!!

JET


User currently offlineMD11Nut From , joined Dec 1969, posts, RR:
Reply 19, posted (12 years 3 months 4 weeks 1 day ago) and read 6434 times:

The DC-8 is probably the only commercial airliner that can safely deploy thrust reversers in the air but that is highly discouraged. Recently one was inadvertently deployed to no ill effect.

I know for sure that the C-17 can deploy thrust reversers for extremely steep descents but then it's a military aircraft.

Regards,
Nut


User currently offlineJhooper From United States of America, joined Dec 2001, 6204 posts, RR: 12
Reply 20, posted (12 years 3 months 4 weeks 1 day ago) and read 6407 times:

A thrust reverser came open on a C-5 back in the Gulf War, causing a crash. I wouldn't try it, because it really isn't needed. Spoilers are more than adaquate on more aircraft.


Last year 1,944 New Yorkers saw something and said something.
User currently offline727pfe From , joined Dec 1969, posts, RR:
Reply 21, posted (12 years 3 months 4 weeks 23 hours ago) and read 6402 times:

The DC-9 can deploy the reversers inflight. There is no mechanical linkage to prevent the thrust reversers from deploying. That's not to say that it's a procedure. The same was true with the 707. Forbidden by the manual, but nothing mechanical to prevent inflight actuation.

User currently offlineExpratt From United States of America, joined Mar 2000, 311 posts, RR: 0
Reply 22, posted (12 years 3 months 4 weeks 21 hours ago) and read 6397 times:

The DC-8s were originally certificated to permit inflight deployment of the T/Rs. But I thought the FOM was revised to prohibit the inflight use of the T/Rs after two crashes where crews deployed the T/Rs on final approach at low altitude. One crash was Alitalia at JFK and I believe the other was IB at BOS. I think both had similar circumstances and outcomes. The airplane broke out of the clouds and were high on the glide slope on short final. The captains did not want to go around and deployed the T/Rs that caused a very high sink rate causing the airplanes to land short and hard. Both airplanes broke up into three pieces, but did not burn. There were several injuries, but no fatalities.

User currently offlineAtlamt From United States of America, joined Sep 2001, 240 posts, RR: 3
Reply 23, posted (12 years 3 months 4 weeks 16 hours ago) and read 6372 times:

I saw a video from Douglas about the flight testing of the md-88. They deployed one thrust reverser inflight (the engine was at idle) and the plane continued along no problem.


Fwd to MCO and Placard
User currently offlineAir2gxs From , joined Dec 1969, posts, RR:
Reply 24, posted (12 years 3 months 4 weeks ago) and read 6320 times:

As far as I know reverser deployment is still allowed, though discouraged on the DC8. JETPILOT, the reversers are still active in flight on the CFM equipped aircraft.

25 737doctor : Air2gxs, you are correct. You can deploy the inboard reversers on 70-series DC-8's in lieu of speed brakes in flight.
26 Bellerophon : Concorde can use reverse thrust in the air. Vc10 was correct, only the inboard engines are used in the air, never the outboards. Reverse idle only, wh
27 Spk : FAA does require the manufacturer to proof that the aircraft can continue flying if the reverser is deployed in flight. In many aircrafts, this certif
28 Jetguy : If I'm not mistaken, the 767 incident resulted in a "Thrust Reverser Armed" max speed limitation of 180 knots being placed on certain aircraft. As I r
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