Reverse in the air?

Mighty · Post by **Mighty** » 07 Mar 2005, 19:55

I thought (in general) it was not possible to select reverse in the air...

but look at this picture.

EBAW_flyer · Post by **EBAW_flyer** » 07 Mar 2005, 20:40

Yes, some old Russian jets can reverse in the air (not only the Il-62 but also the Tu-154).
http://www.airliners.net/open.file/757862/M/
It is also possible in some propeller aircraft.

Mighty · Post by **Mighty** » 07 Mar 2005, 20:49

Okey... I didn't know that.
Thanks EBAW_flyer

waldova · Post by **waldova** » 07 Mar 2005, 23:07

Indeeed some russion planes can do that. I know that on most airplanes it is not possible. It would be to dangerous if suddenly a thrust reverser was deployed during mid cruise. I even thought that a Boeing 737 crashed because of a thrust reverser that got deployed during flight.

Avro · Post by **Avro** » 07 Mar 2005, 23:33

waldova wrote:Indeeed some russion planes can do that. I know that on most airplanes it is not possible. It would be to dangerous if suddenly a thrust reverser was deployed during mid cruise. I even thought that a Boeing 737 crashed because of a thrust reverser that got deployed during flight.

A lauda B767 crashed a few years ago when suddenly the thrust reverser of one of the engines deployed during the cruise.

Chris

SN30952 · Post by **SN30952** » 08 Mar 2005, 16:13

Mighty wrote:Okey... I didn't know that.
Thanks EBAW_flyer

I know that very well, and for almost 25 years now.....
I was on the tarmac on the Findel.
An Aeroflot came in, and reversed in mid-air, but what was the case? The reverse worked only one side, so the aircraft left the runway the other side...
If the reverse had worked only on the other side, that aircraft would have probably come our way.

For the ones who like to investigate on that: search with Aeroflot, Findel, flight coming from HAV and early 1980-ties. No use to add Fons!!!!

What I remember is how quick the crew was out that aircraft, leaving the passengers, see casualities....

5Y-KQV · Post by **5Y-KQV** » 08 Mar 2005, 16:31

Is there a restriction on a max height above which the reversers are not to be deployed in flight?

Cheers,

Walter.

sab319 · Post by **sab319** » 08 Mar 2005, 16:40

I believe the Caravelle could do that too...

Mighty · Post by **Mighty** » 08 Mar 2005, 19:46

I thought nowadays reverse can only be selected when one of the main gears is on the ground.

EBAW_flyer · Post by **EBAW_flyer** » 08 Mar 2005, 21:18

For the ones who like to investigate on that: search with Aeroflot, Findel, flight coming from HAV and early 1980-ties.

Date: 29 SEP 1982
Type: Ilyushin 62M
Operator: Aeroflot / International
Registration: CCCP-86470
Msn / C/n: 1725234
Year built: 1977
Crew: ? fatalities / 11 on board
Passengers: ? fatalities / 66 on board
Total: 14 fatalities / 77 on board
Airplane damage: Written off
Location: Luxembourg-Findel Airport (LUX) (Luxembourg)
Phase: Landing
Nature: International Scheduled Passenger
Departure airport: Moskva
Destination airport: Luxembourg-Findel Airport (LUX)
Flightnumber: 343

BieleAlbatrosy · Post by **BieleAlbatrosy** » 08 Mar 2005, 23:55

B737 classics also have the possibility to deploy thrust reverse in the air, though it needs to have a max radar altitude of 15 or 30ft (don't remember exactly). Don't know if the B737NG's still have that feature.

Jense · Post by **Jense** » 09 Mar 2005, 10:15

BieleAlbatrosy wrote:Don't know if the B737NG's still have that feature.

A friend of mine told me that the modern planes (probably also 73G) have a lock on the reversers.

V-Bird · Post by **V-Bird** » 09 Mar 2005, 12:26

The md-11 has an electronic lock, after touch down of the main gear, the pilot is able to activate the reverse, and when the main gear is still in the air the pilot is not able to activate the reverse. I think most airplanes have a lock like this.

Post by **Bruspotter** » 09 Mar 2005, 12:52

Hello

michael_skypower: VERY NICE PICTURES,...VERY CLEAR!!! 8O :wow:

But I wouldn't know why reversing wile not yet touching down would be so weird. If the speed is to high , there is a risk on a tire-blow-up (or however you might call that). And personally I have even seen aircrafts before , wich were already reversing above the road on RWY25L .

Look to Avro's wich collapses their tail-brakes open before touching down , it's not like a reverser but it is kind the same handling.

Best regards: Yannick

Mighty · Post by **Mighty** » 09 Mar 2005, 13:04

A new member started a look alike subject here
But I think this is a picture of an A340 with main gear on the ground.

I think you don't want to be able to select reverse thrust in the air to reduce speed....
Thats why there are spoilers.

Mighty · Post by **Mighty** » 09 Mar 2005, 13:10

BTW welcome to our new member michael_skypower.

Avro · Post by **Avro** » 09 Mar 2005, 13:35

Bruspotter wrote: Look to Avro's wich collapses their tail-brakes open before touching down , it's not like a reverser but it is kind the same handling.

The Avro's often deploy the air brake in the air indeed, but that's one of the purpose of this device.

Being able to deploy the reversers in the air can be much more dangerous than a deployed air brake which you cannot retract.
IF the air brake is stuck in the open position you can always try to compensate with the 4 engines. But if a reverser is being deployed while flying you cannot recover the plane easily and the result can be horrible. Just look at what happened to the Lauda B767.

Chris

Stoney · Post by **Stoney** » 09 Mar 2005, 13:37

if I have it correctly some approaches require thrust reversing in the air, is this correct?

bits44 · Post by **bits44** » 09 Mar 2005, 14:04

¡ The thrust reverser can be deployed when either radio altimeter senses less than 1 0 feet altitude, or
when the air/ground sensor is in the ground mode. Movement of the Reverse Thrust Levers is
mechanically restricted until the Forward Thrust Levers are in the idle position. When reverse thrust is
selected, the isolation valve opens and the thrust reverser control valve moves to the deploy position,
allowing hydraulic pressure to unlock and deploy the reverse sleeves. An interlock mechanism
restricts further movement of the Reverse Thrust Lever until the reverser sleeves have approached
the deployed position. The movement of the Reverse Thrust Levers into reverse thrust engages
locking pawls which prevent the Forward Thrust Levers from moving. Terminating reverse thrust
removes the locking pawls and restores forward thrust lever movement ability.
¡ When either reverser sleeve moves from the stowed and locked position, the 737 Classics
REVERSER UNLOCKED Light, located on the center instrument panel, illuminates; 737 NG amber
REV indication on the upper DU is displayed. As the thrust reverser reaches the deployed position,
the Reverse Thrust Lever can be raised to detent No. 2 and 737 NG the REV indication turns green.
This position provides adequate reverse thrust for normal operations. When necessary, the Reverse
Thrust Lever can be pulled beyond detent No. 2, providing maximum reverse thrust.
¡ Downward motion of the Reverse Thrust Lever past detent No. 1 will command the reverser to stow.
Once the thrust reverser is commanded closed, the control valve moves to the stow position allowing
hydraulic pressure to stow and lock the reverser sleeves. After the thrust reverser is stowed, the
isolation valve closes.
¡ The REVERSER Light, located on the aft overhead panel, illuminates when the thrust reverser is
commanded to stow and extinguishes 1 0 seconds later when the isolation valve closes. Anytime the
REVERSER Light illuminates for more than approximately 12 seconds, a malfunction has occurred
and the MASTER CAUTION and ENG System Annunciator Light illuminate.
¡ When the reverser sleeves are in the stowed position, a locking actuator inhibits motion of each
reverser sleeve until reverser extension is selected. Additionally, an auto-restow circuit compares the
actual reverser sleeve position and the command reverser position. In the event of incomplete
stowage or uncommanded movement of the reverser sleeves toward the deployed position, the autorestow
circuit will open the isolation valve and command the control valve to the stow position
directing hydraulic pressure to stow the reverser sleeves. Once the auto-restow circuit is activated,
the REVERSER light will illuminate, the isolation valve remains open and the control valve is held in
the stowed position until the thrust reverser is deployed or until corrective maintenance action is
taken.

Michelmvd · Post by **Michelmvd** » 09 Mar 2005, 14:05

It is indeed true that modern high tech airplanes has nowadays reverse systems which can only be selected when one of the main gears is on the ground.
But it is common (at least for the B744 for exemple) that they are deployed before the noise gear is on the ground. This method helps to bring the noise down more gently.

Ciao

Michel