reverse before touch down
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reverse before touch down
I do not know how old this video is and apologies if it has been discussed before , but purely out of curiosity can you put reverse in flight on the MD80 . I know you could do it on the DC8 on the inboards to increase rate of descent , or even on all 4 on the CV990, but never heard it of newer types .
video here :
video here :
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I do not know how old this video is and apologies if it has been discussed before , but purely out of curiosity can you put reverse in flight on the MD80 . I know you could do it on the DC8 on the inboards to increase rate of descent , or even on all 4 on the CV990, but never heard it of newer types .
video here : MD80 reverse
video here : MD80 reverse
in addition to the above, although I believe that on the MDs it is possibile to deploy the reverse at low radio alt, in this specific video You can see the aircraft experiencing a low bounce and then deploying the reversers.
plus Trident and TU-154 and IL62 iirc
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plus Trident and TU-154 and IL62 .... and Concorde
I REALLY SHOULDN'T BE HERE
There was a thread about a while back on this.
737 Reverse before Touch?
Don't try it in a turboprop though.
https://en.m.wikipedia.org/wiki/Nort...nk_Flight_2268
https://en.m.wikipedia.org/wiki/Luxair_Flight_9642
737 Reverse before Touch?
Don't try it in a turboprop though.
https://en.m.wikipedia.org/wiki/Nort...nk_Flight_2268
https://en.m.wikipedia.org/wiki/Luxair_Flight_9642
Last edited by speedrestriction; 28th Feb 2019 at 13:19.
It's a very long time since I was involved with MD-80, but schematic 78-30-1 shows no RA input to reversers. I don't see anything on the schematic that would prevent reverser deployment in flight. Air/ground sensing is used to isolate the reverser accumulators from main hydraulics but does not seem to prevent deployment using the accumulators. My schematics date back to 1981 and there could have been changes since then so I'll defer to those with time on type.
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I was flight lead on an MD-80 series commercial airline trainer a long while ago. Unless there has been a mod since then, the reverser deployment command will not go true unless a main landing gear squat switch is made. In the video, the left main gear is seen to touch down briefly and the reversers deploy shortly after that. It appears to me that the reverser levers must have been in the reverse position, and the first bounce enabled the deployment. A lower order possibility is that one of the main landing gear squat switches was failed closed.
In any case, airborne deployment of the reversers is not a normal operation for the MD-80.
It is possible for the lower reverser bucket to strike the ground if the deployment sequence occurs with the main gear on the ground at higher pitch angles where the nose gear is not on the ground - adding code to detect this was the last change made before the trainer received FAA certification.
In any case, airborne deployment of the reversers is not a normal operation for the MD-80.
It is possible for the lower reverser bucket to strike the ground if the deployment sequence occurs with the main gear on the ground at higher pitch angles where the nose gear is not on the ground - adding code to detect this was the last change made before the trainer received FAA certification.
[QUOTE=twb3;10403017the reverser deployment command will not go true unless a main landing gear squat switch is made. [/QUOTE]
There is no "reverser deployment command" in the actual aircraft. The system is a mechanical linkage between the throttle quadrant and the reverser control valves.
There is no "reverser deployment command" in the actual aircraft. The system is a mechanical linkage between the throttle quadrant and the reverser control valves.
Last edited by EXDAC; 28th Feb 2019 at 15:42. Reason: deleted previous edit
The 737 uses radio altimeter for the air/ground because it has a tendency to float in ground effect and the squat switch doesn't activate - the others use the squat switch.
On the MD-80 nose gear squat is used to isolate the reverser valve from main hydraulics but it leaves the reverser accumulators connected to the reverser valves. Having the main hydraulics isolated from the reverser valves by nose squat does not prevent reverser deployment. NTSB-AAR-81-16 illustrates what can happen if reversers are deployed before nose gear down. Note the procedure change that resulted from this flight test accident.
https://www.ntsb.gov/investigations/...ts/AAR8116.pdf
https://www.ntsb.gov/investigations/...ts/AAR8116.pdf
