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-   -   Helicopter has rough landing at Ski Apache (https://www.pprune.org/rotorheads/613918-helicopter-has-rough-landing-ski-apache.html)

Jack Carson 8th Oct 2018 18:51

Having flown the AS-350B2 at higher elevations (6000 to 10000 ft Pressure altitude) I was always careful to calculate the aircraft performance limitations before and during the flight. At altitudes above 6k we would often run up against the engine’s Ng limits. If you were not careful during high altitude takeoffs or landings the rotor speed would droop when the Ng limit was reached. In one instance I landed at the clinic in White River, Az (elevation 5250 ft.) but not able to takeoff with the addition of a patient onboard due to rotor droop at the engines Ng limit. Just saying that an engine limitation could have been a contributing factor in this incident.

SASless 8th Oct 2018 19:41

Along with the RFM data.....for calculating landing/takeoff performance.....there is also the question of whether an inflight power check was done to confirm the Book numbers.

There are several different ways of accomplishing that I have seen discussed in the past.

Nubian 8th Oct 2018 20:49

Just listen to the sound this poor B2 is making post-impact (from about 0:40 sec). The Nr is well below normal range, and I'm sure at least the engine should have an overspeed check done... The delta Ng would be off the clock, and the cockpit did probably sound like rush hour in Paris.

Impressive amount of luck for the pilot not to roll the damn thing going down the slope, semi controlled. Should buy a lottery ticket!

sycamore 9th Oct 2018 08:58

Target fixation...cleared road,into wind,hover-taxi to pad,reverse route back for take-off....

AnFI 9th Oct 2018 13:19

SASless I little rude perhaps? Of course regardless of which side he was sitting the point remains:
"believing that it was at the height of the ground slightly to the left of his path where he eventually finished, which is probably where his eye was?"

The ground looks the same on top of the bump and below it in the flat area to the aircraft left, where he was probably judging his approach to. With a very constant angle approach the contours would be less obvious since no parallax change between the high part and the lower referenced part of the surface. So he is missing that cue.

It looks more like he just continues his trajectory, untill intended decel later, rather than attempting to pull power and running out. No sign of an attempt to arrest the rate of descent. Was he very heavy? 10k is not that high for a B2.

It's a bit like the tree that 'leaps out on you', he wasn't expecting the ground to be there. Being embarassed he reports a gust, but as Crab points out no sign of that.

It seems he was a very good pilot (with a little luck, but you make your luck too) as evidenced by holding it together during the event.

I speculate that it was an illusion or misreading of the height of the ground.
Any pilot can make errors, even excellent ones, and it looks to me that he was excellent.

I expect this forum is full of people who never make errors.

SASless 9th Oct 2018 13:34

Why the sliding turn just before the descent?

Turning out of wind maybe?

Why such a steep approach?

If realizing he had a power deficiency why not turn downhill and attempt to regain airspeed?

How much high and hot experience did the pilot have?

Did he do hover performance calculations and an in-flight power check prior to doing the approach?

if so....what were the results?

All fair questions?

swisshelipilot 9th Oct 2018 18:02

It's a B3.
A quick review of: LZ altitude 9500ft and temperature (guess: 10-20°C) probably almost 2h of fuel on board, HAA interior with our typical Med Crew and Pilot = 4800-5000lbs, maybe AirCon ON (= 110lbs penalty)
To heavy for HOGE but OK for HIGE. As said before sh....y approach and voila, outcome extremely lucky......:oh:

RVDT 9th Oct 2018 18:07

What can be learned from this thread so far -


Sometimes it is better to remain silent and let people think you are stupid than to open your mouth and remove all doubt
Regardless of the "whys and wherefores" it ticks all the boxes of how NOT to land at a high elevation.

Points of note -

1/ High DA - A guesstimate using historical data in the domain puts the DA at about 12.5K give or take.

2/ Steep approach

3/ Tailwind - no excuse

4/ Runs out of Ng - listen to the audio

5/ Subsequently loses TR authority

Luck had everything to do with the outcome. Nobody injured and at least there is video evidence so that others may learn. Excellent training video!!

Some of the proposition here is astounding.

LRP 9th Oct 2018 20:46


Originally Posted by swisshelipilot (Post 10269773)
It's a B3.
A quick review of: LZ altitude 9500ft and temperature (guess: 10-20°C) probably almost 2h of fuel on board, HAA interior with our typical Med Crew and Pilot = 4800-5000lbs, maybe AirCon ON (= 110lbs penalty)
To heavy for HOGE but OK for HIGE. As said before sh....y approach and voila, outcome extremely lucky......:oh:

FAA Registry shows it as a B2

Washeduprotorgypsy 10th Oct 2018 02:47

Using the blindman's trick for heightening audio perception , this clip is as spectacular to listen to as it is to watch. Guess where the collective is?

Regarding the much needed investigation findings; it's no secret that power corrupts....flying skills.
For operators earning their bread and butter mostly in the flats and valley bottoms with the oddball mission up high....maybe an hour or two of mountain recip. time, twice a year to keep everyone honest.

swisshelipilot 10th Oct 2018 02:53

RLP you are correct it's a B2, watched video on phone and guessed it had long exhaust. Now I would be really interested in the W&B, how did he/she plan to take off with a patient on board in a B2???


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