Colombia B206 crash 20.dec.21
 

There is a good video here:


https://ne-np.facebook.com/SkyHunter...57959727754883


https://cimg1.ibsrv.net/gimg/pprune....bfc3c38d41.jpg
https://cimg2.ibsrv.net/gimg/pprune....e634d1b3a6.jpg
https://cimg3.ibsrv.net/gimg/pprune....33e26952e0.jpg


https://aviation-safety.net/wikibase/271015

Good to see the blades haven't caught on something...
The sound says it all.

Wonder what his pre-flight performance planning involved and if he used a power check to confirm it before committing to landing? I suspect very little and no to be the answer.

Must be tall to get the lever that deep into the armpit. :E

Always best if you can recover RRPM before crashing.

Wish the industry developed the simple gouge we had for the Huey for their aircraft, simple in the extreme. In the Hueys case it was fly at 60 knots at the height you wish to land (or low altitude above the pad), note torque, pull power until rotor bleed, note torque, calculate difference between two torque figures. The gouge then gave figures (forget now but just to make up some) difference of 11 pounds or more OGE hover possible, between 10 and 7 IGE hover possible, between 6 and 4 a zero/zero possible, less than 4 means running landing required.

We had a similar procedure many years ago for the Wessex Megan :ok:

As a rough guide, this has worked for all bell products I have flown, (206B3, 206L4, 407, Huey, 205):

1. Set up for a steep approach to be 100 feet above the obstacle in front of you.... for the sake of explanation we will call this the "decision point". You would aim to arrive at the decision point in a deceleration to little to no airspeed and less than 300fpm descent and almost hover power.
2. Just as you reach the decision point, assuming you have made the approach smoothly, you will push the nose over slightly to stop the deceleration and you will feel a little drop..raise the collective a tad to stop the drop and note your pedal position, TQ and TOT.

From those numbers you need the following to hoverIGE:From those numbers you need the following to hover OGE.a. An extra one and half inch of left pedal
b. An extra 15% TQ
c. An extra 50 degrees of TOT

How does that work with a headwind say 15 kts?

One has to assume the wind will be roughly the same once down close to the ground and works fine, just zero the ground speed.

Of course ass others have noted there are other ways to check also, can you maintain 300 fpm climb at 60kts you should be able to hover, you can also try HOGE at the same altitude MSL, but next to the pinnacle with 100' AGL to be able to get out if you cannot hover, Many different ways to check.

And if all else fails you could read the performance section of the RFM I suppose?

Well let's not get too logical..... lol

Fixed wing driver here.
So you guys are saying at that altitude above MSL he didn't have enough available power to hover OGE then proceed to a safe landing?
When he pulled more collective, main rotor RPM decayed and the horn sounded...
Is the procedure Gordy is referring to effectively giving you the option to put the nose down and fly away from the landing attempt if you don't have enough power while still having sufficient altitude?

Yes, but that is the key phrase.... Altitude and/or speed are your friend.

Well, its a good start. But as winds, turbulence and downdrafts not always is faverable, a HOGE according to the chart on the spot isnt always possible.

I havent ever really been on the wrong side in the charts but still aborted at least hundred landings(or final touch down part of) due to insufficient power/reaching max allowed torque etc.

Tartare - in simple terms, a helicopter uses more power to hover than it does in cruise flight and so speed is your friend.

If you haven't got speed but have the altitude to dive on speed, then that is also your friend.

The difference in power required from zero airspeed hover to 15 to 20 Kts IAS is very marked and so, coming below that speed without having sufficient power to hover is going to cause you problems - as in the Colombian accident.

He could have made a steeper approach, all the way to the ground without coming to the hover at all - the brit mil call this a zero speed landing - but he would have to offload pax before trying to depart.

As AAKEE says, the winds around hills are often at odds to the main flow with up and downdraughts and turbulence - that is why HOGE power isn't enough, you need a thrust margin to allow for those factors if you want to stay safe.

Gordy - your technique actually seems very similar to the LDP for many PC1 profiles.

Any wind is always to your advantage and the stronger the better. Makes it easier to identify as there are more cues. And in my experience I have never seen the wind blow into the ground. Steep approach to a site like that is textbook myth that unfortunately is still talked about. Pinnacle approach is much easier done climbing up to the site from below. If you run out of performance it will be patently obvious. The aircraft will turn around on its own to face back where you came from! The type of approach in the video without knowing your performance and verifying is just “suck it and see”. As with most things in aviation “ hope” is still not a good strategy! Seems that flight school must have been just a convenient lunch venue?

“Altitude is your friend”.

Aircraft performance reduces with increasing altitude so it’s probably more correct, in a case like this, to say that height above the surface is your friend…

Yes, that would be a better way to put it..... I was attempting to be concise.

Very interesting - thank you gentlemen.

That is simply untrue, I've used that day and night in hot and high situations in the past.

Coming level or for beneath retaining an escape route is a great technique and one I have used and taught many times over the years, especially at night where rates of closure are more difficult to assess.

However in the Colombian accident it doesn't look like he thought about escape routes as he could have approach from a slightly different direction and retained the ability to dive away as he got to Nr decay.