Aug 1. 2017: MD Explorer crashed in the austrian alps

[atakacs]

Amazing that no one was seriously hurt or worse.
Can anyone confirm the flight envelope of this aircraft?

[Flying Bull]

Originally Posted by Hedski

Can NOTAR suffer LTE given the jet of air is pushed out of the tail boom?

Its a combination of air pushed out with airflow modified over the tailboom...
So yes, LTE is possible

https://en.m.wikipedia.org/wiki/NOTAR

[[email protected]]

Certainly looks like classic LTE/LTA even though there isn't actually a TR involved - undemanded/unexpected yaw that wasn't/couldn't be brought under control.

Perhaps the best option was to transition to forward flight.

Initially I thought such a sharp mountain feature might produce violent gusts but the video shows quite a laminar and steady flow.

[Thomas coupling]

Correctomondo Crab the Notar does have a tail rotor - but it's parked up where the sun don't shine!

I reckon it's a mixture of gusty conditions and light on the skids. Skid digs in and ooops a daisy.

[nigelh]

I see no relevance to a skid digging in or any sign of that . Also no sign of TR fan failure ( the spin would have been far more aggressive ) . Either he just ran out of pedal ( pulling too much power plus wind on tail ) or never gave it full pedal ( unlikely as a professional ) . He would have done better to take off when he realised he was in bad spot and found better place to land properly or find a place he could be light on skids but into the wind .

[Hot and Hi]

Originally Posted by Flying Bull

The Johann hut - is 3.454 m ASL - about 11.300 feet....
https://de.wikipedia.org/wiki/Erzher...ann-H%C3%BCtte
With the chart given - the gusts may well have exceded the demonstrated limits.....

To add insult to injury: Mid summer on the mountains. OAT most likely well above ISA.

[Aucky]

https://ibb.co/n2m76a
Seems they were a bit high for HOGE (not sure of OAT) and ran out of pedal. Nose down the valley would probably have been the best action, in hindsight.

The linked graph is the 207 variant, the 206 (if fitted) performing a little less well at altitude.

[Thomas coupling]

Nigel me old stalker you obviously didn't pass German O level or is it "Ö" - Stufe.

Zuerst haben die Kufen den Boden berührt, dann ist die Maschine umgekippt, und dann hat der Rotor den Boden berührt.“

.

What do you think happened now after reading that............................

[Flying-dutch]

TC, did you look at the video of the accident?
you don't need to understand German to see it's spinning out of control instead of a rollover due to gusty winds.

And when you do speak German (as I do) you do put question marks comparing the video and the first statement.
But the final report will reveal it all I guess.

[jymil]

Originally Posted by nigelh

He would have done better to take off when he realised he was in bad spot and found better place to land properly or find a place he could be light on skids but into the wind .

Yep, putting it into the wind in the first place would have been better. Sometimes it's hard to judge the wind, but in this case they had people on the ground being capable to tell the pilot. In picture #2 of post #9 it also looks like landing into the wind would have been possible on this spot.

[[email protected]]

Correctomondo Crab the Notar does have a tail rotor - but it's parked up where the sun don't shine!

so it's not a tail rotor then Its a fan blowing air down the tail boom to the coanda slot and the buckety-blower arrangement.

[jymil]

Originally Posted by [email protected]

so it's not a tail rotor then Its a fan blowing air down the tail boom to the coanda slot and the buckety-blower arrangement.

Check the causes of LTE: https://en.m.wikipedia.org/wiki/Loss..._effectiveness

1. Main-rotor vortexes pushed into the tail rotor by wind.
2. Wind from the tail (6 o'clock) can cause the helicopter to attempt to weathervane into the wind.
3. Wind moving in the same direction as the tail rotor moves air

1 cannot happen with NOTAR, but it is not prone against 2 and 3.

[[email protected]]

It's got big vertical stabilisers which can help it weathervane into wind and combinations of rotor downwash and crosswind can affect the coanda flow on the tailboom.

Don't rely on wikipedia ffs.

[Ascend Charlie]

LTE???? Har har har, the Bell Spin Team is high-fiving and celebrating the total brainwashing of the junior rotary community. The term LTE is firmly embedded in the skulls, and is brandished whenever some poor coot runs out of power pedal, be it from altitude, bad wind direction, or pilot pushing his luck.

With a NOTAR, surprise surprise, THERE IS NO TAIL ROTOR. Yes, he may have run out of anti-torque power, but it ain't LTE.

It certainly looks like a simple case of running out of power, a right turn which doesn't get corrected, the momentum builds up, a bit of nose-down pitching occurs, and splat, or as they say hereabouts, Geschplattenzerden.

[Thomas coupling]

I do apologise most profusely, this reference people are making to a video? I've only just found the link by scrolling thru from the beginning again! Ooops.

As Ascend Charlie states, this is most definitely loss of directional control due to the major gusts he was obviously experiencing. The gusts must have robbed him of most of his coanda effect thus making directional control more sensitive and he moves into pilot induced oscilating in yaw and then the nose dips.
Quite frankly, he must be one of the luckiest guys on the planet - if she had rolled to port instead of the way she did go, he'd have fallen a n enormous distance to his untimely end.
Correct - NOTAR's don't suffer from LTE (no helos do except OH-58's and some 206's but there is an argument for them losing LTA during certain cross wind/tail wind situations and at the bottom of auto's (even though the TR is in the cone, it's still a tail rotor design but not situated at the end of the tail cone but at the beginning..

Ascend - when did you retire. You must have gone well past 40 yrs of flying?

[nigelh]

An apology from TC .....the whole world has gone crazy 😱

[[email protected]]

AC - It certainly looks like a simple case of running out of power, a right turn which doesn't get corrected - can't make the quotes thingy work today

The second part is clearly correct - how do you come to the conclusion that he ran out of power?

LTE is, as has been discussed before, an invention of Bell to explain their TRs aren't big enough but it has become a useful term, along with LTA to explain yaw deviations due to aerodynamic or mechanical (LTA) reasons

[handysnaks]

As it is 10 years since I last flew a 902, the memory has faded a bit but I do seem to recall the RFM showing a prohibited sector of about 60 degrees of relative wind direction from one of the rear quarters, above certain altitudes, but like a bus, if we wait a bit, a proper 902 pilot should come along to give a more educated 'guess'

[skadi]

Originally Posted by handysnaks

As it is 10 years since I last flew a 902, the memory has faded a bit but I do seem to recall the RFM showing a prohibited sector of about 60 degrees of relative wind direction from one of the rear quarters, above certain altitudes, but like a bus, if we wait a bit, a proper 902 pilot should come along to give a more educated 'guess'

See post #15

skadi

[handysnaks]

Ahh, that's the one. I obviously missed it in my hurry to post before the actual reason is known