thrust reverser debate ...i won....sort of.

[Splitpin]

A little bit left field , but ive having a debate with a dude about the use of thrust reverse prior to , or just before touch down. Im sure i can recall seeing the old ANZ DC-10's in reverse thrust in the flare.
Sure enough ... in the latest "AERO Australia" theres a photo of an IL-62 with reverers deployed while still about 3 or so mtrs above the tarmac.

Can anyone confirm if im right about the DC-10's ....not a biggy , just interested.

edit: Come to think of it ... given the spooling effect associated with jets.... there is probably no reaction until touchdown anyway, if they are deployed at just the right time .... so maybe i did see those old DC-10's as i remember.
I do recall recently , a USAF C-17 "backing" out of one of the international gates at CHC , as no tug was around. And it was common practice with some U.S carriers back in the 90's , to reverse out of the gate ..... why Im not sure...can a push back cost so much?

[Ex ANZ Eng]

QUOTE (Splitpin @ Mar 24 2013,4:55 AM) <{POST_SNAPBACK}>

A little bit left field , but ive having a debate with a dude about the use of thrust reverse prior to , or just before touch down. Im sure i can recall seeing the old ANZ DC-10's in reverse thrust in the flare.
Sure enough ... in the latest "AERO Australia" theres a photo of an IL-62 with reverers deployed while still about 3 or so mtrs above the tarmac.

Can anyone confirm if im right about the DC-10's ....not a biggy , just interested.

edit: Come to think of it ... given the spooling effect associated with jets.... there is probably no reaction until touchdown anyway, if they are deployed at just the right time .... so maybe i did see those old DC-10's as i remember.
I do recall recently , a USAF C-17 "backing" out of one of the international gates at CHC , as no tug was around. And it was common practice with some U.S carriers back in the 90's , to reverse out of the gate ..... why Im not sure...can a push back cost so much?

Mmmm....not sure about the DC10's, nowdays, at least, I am pretty sure that reversers (and spoilers) wont deploy until main gear compression.
I do know that the old 737-200's have been known to reverse out of a gate, had an old work mate who showed me pics of one in Canada when he was working the ramp.

[Splitpin]

QUOTE (Ex ANZ Eng @ Mar 19 2013,6:26 PM) <{POST_SNAPBACK}>

Mmmm....not sure about the DC10's, nowdays, at least, I am pretty sure that reversers (and spoilers) wont deploy until main gear compression.
I do know that the old 737-200's have been known to reverse out of a gate, had an old work mate who showed me pics of one in Canada when he was working the ramp.

Thanks Phil ..... maybe i was wrong.

[Ex ANZ Eng]

QUOTE (Splitpin @ Mar 24 2013,5:30 AM) <{POST_SNAPBACK}>

Thanks Phil ..... maybe i was wrong.

I may stand to be corrected, but from what I understand the cause of the Air NZ DC8 crash at Magere back in the 60's, was due to the training Capt pulling an eng into reverse just before touchdown which resulted in an unrecoverable yaw one way.
Apparently, instead of pulling the eng back to idle, he overshot it and pulled it right back into reverse resulting in the unrecoverable yaw.
Something in the back of the grey matter makes me think that this resulted in future designs not allowing reveresers to deploy until main gear compression and the introduction of separate reverser levers attached to the throttles.
I would assume that any aircraft that can do it are probably starting to get pretty long in the tooth and are made by companies with an unpronouncible name.....lol
As for the DC10's.......I am not sure, I may have to do some research...

Ahhhh, good ol Wikipedia....quote below.
In-flight operation

Some aircraft are able to safely use reverse thrust in flight, though the majority of these are propeller-driven. Many commercial aircraft cannot use reverse thrust in flight. Exceptions include Russian and Soviet aircraft that are able to reverse thrust in flight (mostly before touchdown). 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.

The Hawker Siddeley Trident, a 120- to 180-seat airliner, was capable of descending at up to 10,000 ft/min (3,050 m/min) by use of the thrust reversers, though this capability was rarely used. Concorde, too, could use reverse thrust in the air to increase the rate of descent. Only the inboard engines are used, and the engines are placed in reverse idle only when subsonic and below 30,000 ft. This will increase the rate of descent to around 10,000 fpm.[citation needed] The US Air Force's C-17A is one of the few 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 (this means that the aircraft's descent rate is just over 170 mph, or 274 km/h). The Saab 37 Viggen (retired in November 2005) also had the ability to use reverse thrust before landing, enabling the use of many roads constructed in Sweden to double as wartime runways

Whew.....what a read, damn interesting tho....
I do know that there are records of uncommanded reverser deployment on DC10's during flight.
Hope that helps Splitpin, you were right

[SA227]

I just did a bit of looksey and the first interesting thing I found was that the DC10 employed pneumatic motors and not hydraulic actuators as one might expect.
It would appear that the aircraft had 2 independent lock out systems 1) a logic circuit that detected wheel spin as well as radar altitude and 2) a squat switch on the nose gear. Boeing brought out an AD back in 2000 which added a 3rd system which apparently directly connects the reverse thrust lever to a physical lock to prevent inadvertent inflight deployment.

So to answer your question, it would appear that they could not intentionally be used inflight

[Splitpin]

Thanks very much guys ..... very interesting, the forum at its best.

[Ian Warren]

Was a case in the mid late 1980 , recall was a MD80 and reverser's going on causing a fatal crash - went on from that all aircraft were retrofitted i believe all three point had to be on the ground or below a specific speed before they kicked in .

[Splitpin]

QUOTE (Ian Warren @ Mar 20 2013,1:54 PM) <{POST_SNAPBACK}>

Was a case in the mid late 1980 , recall was a MD80 and reverser's going on causing a fatal crash - went on from that all aircraft were retrofitted i believe all three point had to be on the ground or below a specific speed before they kicked in .

Thanks Ian ...... lots of information. Im still interested in this photo of the ILl-62 with them clearly deployed ....I'll see if i can copy it and post.
Thanks again gurus

[Ian Warren]

The Russians tho are real tricky tricksters ... Mig29s and all sorts of fighter deploy brake chutes and the lots when still 3/4 meters of the ground and not even over a runway ... so would surprise me if they diddled around with an Il-62 in the same manner ! arr those 'Vodkas' can make ya do weird things

[Ex ANZ Eng]

QUOTE (Ian Warren @ Mar 25 2013,12:54 AM) <{POST_SNAPBACK}>

Was a case in the mid late 1980 , recall was a MD80 and reverser's going on causing a fatal crash - went on from that all aircraft were retrofitted i believe all three point had to be on the ground or below a specific speed before they kicked in .

Mmmm, dont think so Ian, used to see 767-200's come in for a greaser landing after a red light on the nose gear, they did a greaser landing and held the nose off till the very end......mains on ground and reversers deployed.
Tuened out that it was just rubber debris on a micro switch on the nose gear that indicated that nose not down and locked.
Even a flyby the tower would never confirm so a greaser landing was the orderof the day....

[Ian Warren]

QUOTE (Ex ANZ Eng @ Mar 20 2013,7:00 PM) <{POST_SNAPBACK}>

Mmmm, dont think so Ian, used to see 767-200's come in for a greaser landing after a red light on the nose gear, they did a greaser landing and held the nose off till the very end......mains on ground and reversers deployed.
Tuened out that it was just rubber debris on a micro switch on the nose gear that indicated that nose not down and locked.
Even a flyby the tower would never confirm so a greaser landing was the orderof the day....

It may have been only the DC-9/MD-80-95 series this was adjusted on , those things had a rear horrid issue to fall out the sky .. , more likely on that class off aircraft were given spec's to follow hence reason we never really saw the type in the NZ

[Ex ANZ Eng]

QUOTE (Ian Warren @ Mar 25 2013,7:02 AM) <{POST_SNAPBACK}>

It may have been only the DC-9/MD-80-95 series this was adjusted on , those things had a rear horrid issue to fall out the sky .. , more likely on that class off aircraft were given spec's to follow hence reason we never really saw the type in the NZ

I think its fare to say that apart from Mil apps, times have changed and the 'majic box' wont allow for any driver errors in mid air......mind you, I still prefer to have an experianced driver up front....

[nzav8tor]

Lauda Air 76 was lost over Thailand in 93 due to a thrust reverser deploy in flight. Very dangerous if its asymmetric like that.
http://en.wikipedia.org/wiki/Lauda_Air_Flight_004

The GIV Shuttle Training Aircraft was capable of inflight reverser deploy to simulate the shuttle approach.

Our Gulfstreams use a combined weight on wheels switch (2 out of 3 to determine the mode air or ground) and wheel speed spin up taken from the main wheels. An electrical latch then releases allowing the piggy back levers to be lifted into idle reverse.

The more dangerous thing is ground spoiler deploy in flight. A GIV was lost some years back in Savannah. The weight on wheel switches were put into air mode to test a system. They did this by wedging popsicle sticks into the microswitches . The engineers forgot to remove them prior to flight, crew armed the spoilers on approach, power to idle on final somewhere and bang - up they went. Plane dropped out of the sky.

[Ian Warren]

QUOTE (nzav8tor @ Mar 20 2013,9:52 PM) <{POST_SNAPBACK}>

The GIV Shuttle Training Aircraft was capable of inflight reverser deploy to simulate the shuttle approach.

Yeah - Exactly .. very heavely modified aircraft to train SS pilots and tweaked and twisted to get the best senerio ... fly without nose wheel down till the last second s ..

Think the biggest problem with rear end jet is COG when throttle up/down or reverse kicks in .. fine with ya bananas glued to the wings - mid wing'd least some control .. you stick a wrong way firework up your jacksie and see how you like it .... your all over the place .

[TonyM]

I flew on an American Airlines MD80 in Apr94, seated in about the second or third row from the back.

At KDFW ready for dep to KATL, when all of a sudden, a terrific roar at the gate, and we backed out!!!!

Only time I ever experienced that !!!!

[cowpatz]

The DC8 regularly used reverse on the inboards as they had no speed brake. The DC10 was unable to deploy the reversers in the air. One of the reasons this would undesirable is that should a baulked landing (late go around) be required it could not be guaranteed that the reversers would stow symmetrically (if at all) and this would lead to a very dangerous situation that would probably not be recoverable from. We are trained that once the reversers are deployed there is NO go around for this very reason. The Lauda air 767 reverser deployed due to a fault that should never have happened.
Having practiced this in the 767 during a RW simulator detail I can say the Lauda crew had very little chance for recovery. Even Boeing instructors could not control it without advanced notice and much practice. So serious is the effect that the QRH (Quick Reference Handbook) was amended to read words to the effect of: "In the event of a thrust reverser deployment place the fuel control lever to cutoff". Normally before shutting any engine down first the Thrust lever is confirmed with the other pilot and closed to idle followed by identification of the correct fuel cutoff lever before placing it to the cutoff position.
There are interlocks on the throttles that prevent reverse thrust application until certain conditions are met. On the 747 one of them is retraction of the inboard leading edge devices as well as landing gear proximity switches (squat switches) .

[Ian Warren]

Brilliant CP .. I heard the eight lacked speed brakes but using the engine but only inboards I did not no , very dang interesting .

[SA227]

Managed to locate a Flight Crew Operating Manual for the DC10 and interestingly it would seem that you could possibly get reverse thrust from engines 1 & 3 in flight.

Initial reverser lever movements starts reverser deployment. For engines 1 and 3 reverser lever cannot be raised past reverse idle detent until reverser is fully deployed. For engine 2 reverser lever cannot be raised past reverse idle detent until reverser is fully deployed and nose gear ground shift mechanism actuates.

On airplanes with SB78-40 or production equivalent, an in-flight reverse thrust interlock prevents deployment of thrust reverser's unless landing gear is down.

There is no mention of the logic circuit I found in another reference so may be that was a later modification.

A remember a number of years ago I ferried an aircraft that was owned by a former Air NZ DC10 Captain and he did tell me that under certain conditions you could apply reverse thrust on the number 2 while in the taxi and actually lift the nose off the ground which probably explains the nose wheel squat switch.

[Splitpin]

Wow ...again, thanks guys.....what an "infomine" this place is..... just wish i could find that photo of the 62 .
Thanks again for all the effort.

[scaber]

QUOTE (Splitpin @ Mar 24 2013,6:26 PM) <{POST_SNAPBACK}>

Wow ...again, thanks guys.....what an "infomine" this place is..... just wish i could find that photo of the 62 .
Thanks again for all the effort.

Maybe this one?

http://www.airliners.net/photo/LOT---Polis...-62M/0945012/L/

or this one?

http://www.airliners.net/photo/Air-Koryo/I...-62M/0790494/L/