S-92 Power Off Landing.....

[vaqueroaero]

Here's a clip of a full down in an S-92. Thought everyone would like to see it!

http://www.youtube.com/watch?v=4JqmoWAhv5g

[212man]

If you listen carefully, you can hear the EGPWS shouting "Tail too Low"!!

[finalchecksplease]

Always wondered if test pilots shut down the engines for these power off landings for certification flights in heavy twin aircraft or just put them back to idle?

Care to give us so tips on how best to do these Mr Lappos, you must have done loads of these.

Greetings,

Finalchecksplease

[NickLappos]

Levers in idle is satisfactory, as long as no appreciable power is extracted from them.

[Overt Auk]

"Mr Lappos, you must have done loads of these"

I understand that the S92a certification required just one full down auto, the one you see here. Having seen it, I don't think anyone would choose to do more for the fun of it.
OA

[ShyTorque]

But surely, both engines off is best, so that the autopilots drop off line?

[NickLappos]

Actually, they don't. The generators on the 92 are driven by the main transmission, so if you have Nr, you have the juice!

[ShyTorque]

But Nick - surely that means a change from the Sikorsky mantra!

It can't be the right way to do it at all - Eurocopter, sorry Aerospatiale, similarly did it wrong in about 1970 with the Puma...... an' wot's more, even the blades go round the wrong way on those

[JohnDixson]

Nick is almost correct re the procedure: Power Levers stay back, out of governing, but forward of Idle. The reason is simple: if the flare doesn't look good, one wants power in a hurry and doesn't want to wait for the spin-up time from Idle.

Actually we made two landings that day. The first one came out Ok, but the telemetry boys noticed that there was a tweak of one of the power levers and a bit of torque got to one of the engines. Bob Spaulding had his hand on the power levers and was just keeping them in the mid to low 90's Np-wise. The amount of torque that we obtained out of one of the engines was tiny: a percent or two, but rather than have a very complicated meeting with the certification authorities, we decided on the spot to do another landing, went around the pattern and did the one on the video.

I like the comment re the EGPWS! Knowing where the tail and of course the tail rotor is, that is to say, their clearance from the ground plane, is tougher as the size, i.e., length, of the helicopter goes up. For the practice power recovery autorotations that just preceded the actual landings, we had an observer with a radio on the grass next to the runway who gave us a visual ground clearance value for each flare. After a few, one got a feel for where the back end was. Well, for the most part anyway.

[finalchecksplease]

Thanks for all your comments, didn’t think that one would shut down the engines, just in case it didn’t look good towards the end but one is never sure what the certification rules require.
Mr Dixson it looks to me the video shows the two landings or is it just a different camera angle (looks like a bigger flare in the first one).

Greetings

Finalchecksplease

[JohnDixson]

I think you are correct, with the side view being the first landing.