Edited by r22butters, 21 February 2018 - 23:30.
LTE,...or perhaps a different gremlin? What do you think?
Posted 21 February 2018 - 23:30
- TeoerryNug likes this
Aaaaaaaany day now!
Posted 21 February 2018 - 23:58
What the heck did he expect to happen???
* Already at 100% Tq (nothing left)
* Already at full left pedal (nothing left)
*Already had low RPM warning horn on, (losing anti-torque power with decreasing RPM)
.....but he still tried to slow down more for the landing.
No, this wasn't "LTE", this was simply not having enough power, or left pedal, to make the approach. It certainly wasn't "unanticipated yaw" because any pilot should have anticipated this would happen.
- Hand_Grenade_Pilot likes this
Posted 22 February 2018 - 18:17
You are exactly right, Eric! It was typical pilot dumbassery. It was a classic case of a (probably young) pilot exceeding the performance limitations of the aircraft.
But see, pilots would rather blame the machine than themselves. Ol' Clint could have said, "We were at the power limit, and a control limit and we were still coming down, so I should have expected that something bad would happen." But no, he pushed on and seemed (still seems) surprised that the ship rotated. And now we have yet another bonehead NTSB guy who believes in LTE and that's it's the fault of the aircraft.
Hey, I got some free advice for you new guys out there: Anytime you're on approach and you hit a limit of any kind, ABANDON THE FRIGGIN' APPROACH and go figure something else out. You're welcome.
- Wally, Mikemv, SBuzzkill and 2 others like this
Posted 22 February 2018 - 18:47
High DA degrades tail rotor authority.
High GW requires more anti-torque.
Certain wind angles can degrade tail rotor authority or cause a strong weathervane tendency.
These factors can be managed, if the pilot knows what they are doing.
But allowing the helicopter to rapidly yaw and subsequently losing control is 100% pilot error, regardless of how you dice it. I was not impressed with his analysis of the incident; I see a (former?) pilot blaming the aircraft (206 vs the 206L3) and job pressure while missing the variables that created the problem.
He lacked the knowledge and experience to realize that being at 100% TQ, still above ETL, on approach to a pinnacle is a disaster waiting to happen. It snowballed into dragging the RPM down (which means that he was over-temping or over-torquing the hell out the aircraft) and ultimately lost so much TR authority from dragging the RPM down that he lost control.
In a turbine aircraft, if you are drooping rotor rpm, you are creating a major exceedence. You are losing RPM because the engine can not produce any more power; drag exceeds everything the engine is putting out. And in order to reach that point, you will be well beyond your TQ, NG, or TOT limit. Total power available goes beyond the red line. Its not like a recip engine with no MP limit; in that case, reaching 100% output is fine by design. That is why he landed to check the aircraft out. Conviently leaves out the why, while claiming TQ was only at 100%. He had that thing pegged into the transient and more than likely ruined the engine and transmission.
All that needed to be done was a power check early in the approach (or in his case, understanding what a power check is). Reduce a bit of collective, nudge the cyclic to get best RoC airspeed, do a go around, drop weight at an open LZ that allows a normal approach, and then do the pinnacle drop off in two or even three trips.
But yeah, lets just blame that whole thing on LTE and human factors, instead. From an NTSB rep of all people, go figure.
- Wally, Cod, apacheguy and 1 other like this
Posted 23 February 2018 - 09:40
NTSB Saftey Alert Video - Overpitching
With the emphasis being that improper planning and technique in a performance limited environment can be catastrophic.
And then included notes and interviews from real experts on proper performance planning and approach techniques. In addition to stressing the importance of conducting a power check before reaching a point in the approach where you are committed. That would be much more informative to an inexperienced pilot then placing the bullseye on the symptom rather than the cause.
Posted 24 February 2018 - 17:31
Surely the video is made to make people think.
As a low hours pilot \private If I maxed out any single limit my self preservation would be telling me
"DO NOT CONTINUE" you are heading for a world of hurt.
Please tell me that it is not a serious view of the incident
- Wally likes this
Posted 24 February 2018 - 20:15
He came in downwind. 95% of problems in a helicopter can be avoided by not coming in downwind.
- apacheguy likes this
Posted 24 February 2018 - 23:18
The sad part about the video was the NTSB dill saying that it was LTE and that every single-rotor machine was susceptible to it.
Horse feathers. If it ever existed, it was purely a B206 problem, and usually the small-tail-rotor version. Never had enough anti-torque power, right from the design, but the spin merchants invented LTE to cover up the fault. And then when the NTSB stands up and declares it to be LTE, it gives a pilot a ready-made excuse for stuffing up.
"Oh, not my fault, it was Dolly..... err...no, it was LTE."
Posted 25 February 2018 - 06:57
Here is another video of a very similar pinnacle approach that didn't end well. Lessons learned - power check and know wind direction.
Props to our high time guys here for their wisdom.
Posted 25 February 2018 - 09:57
Anticipate the situation: know where, what and how your proposed flight might be limited and fly the aircraft with a REAL plan to deal with the limitation by eliminating, minimising or aborting, if and when whatever limitation starts to appear to minimize, prevent successful execution of whatever maneuver.
You do fuel planning, right? You do performance planning too. You do weight and balance. You plan the safest flight path. All these and more are planning to stay within limits. Oh, and relative wind direction, it's effect on performance will be an issue- downwind is fast, upwind is slow, and crosswind is somewhat slow... because the aircraft doesn't know where the wind is coming from, only the pilot. You have to plan for these things.
"Always make your approach to land into the wind. Amen." Yeah, sure. After you are on the 'pad' over the landing point, might you turn the aircraft to clear the tail rotor? Or you might turn it to avoid exposing ground personnel to the hazard. Or lots of reasons, but if you do so, you think about control limits, right? It might even be reasonable to turn tail into the wind!!!!
Might you not dog-leg the final? How high is too high to do that? The aircraft doesn't know that you dog-legged and now you're crosswind or downwind, only you know and you should have considered control, power, emergencies before you did it, and you did it for good safety reasons, right? Good safety reasons MIGHT even require a significant portion of your approach (or other operation) be tail into the wind... Like, which is better- a power failure followed by a perfect auto into-the wind zero ground run but into terrain that will destroy the aircraft? Or a sliding auto, downwind onto a 6 lane highway? Like the man says, the aircraft was broke when you initiated the engine out landing, now it's making your survival an issue- you owe the airplane NOTHING, it owes you crash safety and survival.
So, go in downwind if that's what it takes to maximise the probabilities of everybody avoiding injury. But know that you can't fly it like a solo student pilot might do, into the wind, to the runway numbers. Your approach might be high and hAVE extremely slow rate groundspeed, it might even zig zag all over. Or it might be low, flat or even rise to reach the landing. You might abort a couple times if turbulence bounces you around, twitches the tail, or a pax in back drops something (ha ha ha. You scared me...) but you planned the path and angle so that the aborts were annoying delays, and didn't 'render the successful outcome of the planned maneuver doubtful'. And you adapted the plan after each attempt to eliminate whatever issue you encountered in previous attempts. As to LTE, if the yaw/power required equation looks problematic at any point in the approach, or the tail wiggles the least bit before I'm comfortable....
Or you might just say, well I can't do this, and go home. That is success, going home.
Edited by Wally, 25 February 2018 - 10:07.
- Hobie likes this
Just a pilot (retired, so I have a LOT of time)...
Posted 25 February 2018 - 10:51
The lesson I'm taking from the video is that, if you feel pressed for time, force yourself to stop for a moment, relax, and really think about what you're about to do.
Rushing to get the job done is the best way to cause an accident!
Aaaaaaaany day now!
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