Added: 3 years ago
From: mushatrusha
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  • I thought LTE before anything even happened based on the shape of the mountain and most likely direction of wind in into the tail rotor blowing the turbulent air back in causing the right spin.

  • This is grim but very interesting. See at 0:32 main rotor sheared off and went skyward - with the mainshaft attached by the looks. There was a person on the summit near the start - hope they didn't get clobbered by bits! It's obviously a Bell Jet Ranger by the shadow and sound.

  • Perfect example of loss of tailrotor drive. You actually can see the helicopter yaw and the pilot almost emmediatelly does what the emergency checklist tells: collective pitch reduce to stop yawing. You can hear the N1 turbine speed down, when you listen closely to it. He just is to Slow n low to recover the chopper. Bad Luck beeing in the dead mans curve when tailrotor quits service.

  • Everyone is an expert.

  • definitely LTE----at the crest the mountain, mountain roll wind is a bitch!!!

  • How come the pilot doesn't cuss?

  • LTE? someone please explain this for me?:)

  • Glad to see the NTSB guy in the top-comments section,lol

  • I think shootbigbird got this one right, altitude is high and it's a perfect spot for the wind to rotor requiring an increase in collective to hold altitude resulting in over pitching and then, oh my gosh there's no more left peddle. thank you for the posting as it's educational to watch it unfold, hope the punters came out ok.

  • Wow, I can't believe that none of the comments posted the true cause. It was downdraft rotor, from the 40 mph wind hitting the sharp ridge. The helicopter flew behind the ridge, into the curling rotor wind and it forced him down to the ground. Glider pilots know all about this rotor because they fly near mountain ridges and they know never to get behind ridges in strong wind.

  • I find it somewhat strange that comment after comment is about the tail rotor or some mechanics or the other but no one mentions or tries to find out if these pax in the chopper survived!! Did they?

  • "A helicopter impacted the top of Pike's Peak at 14,100 feet mean sea level (MSL). The pilot said he had made a low pass over the summit into a 40-knot headwind before losing tail rotor effectiveness. He then lost directional control and struck the ground." source: dynamicflight.c o m/aerodynamics/loss_tail_eff/

  • this is one area where fixed wing aircraft have an advantage. you don't often here of wings breaking off fixed wing aircraft but it has been known to happen but usually due to over stressing the airframe. i hope they survived this

  • ...this

  • Well I think they.... died. But who has uploaded

  • ship was in a continuous left strafe and it sounds like a 206 so more than likely was lte/tr vrs.

  • This is very interesting and obviously appearances can decieve.

    So can anyone advise details as to groundspeed ,Airspeed,weather conditions, altitude/temperature/density altitude.

    What machine/version was it and what weight.

    Then its time to get the performance data out!!!

  • Didn't look too bad right?

  • lol

  • Yeh Im calling this VRS too ....that lead to LTE. High density altitude reduction of power and high rate of descent for that altitude. The pilot got in trouble but had insufficient altitude in order to recover.

  • lol @ the rotor blade flying off in the last frame

  • Tell me as I am uninformed What is LTE?

  • @KC8YOQ Loss of Tail Rotor effectiveness, which is loss of tail rotor thrust and anti-torque capability from aerodynamic causes (excluding mechanical failures) like tail rotor ring vortex state, main rotor tip vortex interference and weathercock stability, to name a few.

  • Thanks! Did all survive the crash?

  • Tail rotor vortex ring state?  Mountain flying is a bitch!

  • Yes, causing the LTE

  • @lukefled ya..thats true

  • My vote is in for LTE

  • Owch

  • Poster please can you provide further info please.

    Dramatic footage.

    Initially I would doubt LTE, as the airspeed is too high. Appears more like a tail rotor failure.

  • This and the other video you commented about, were shown by Bell Helicopter Textron as examples of LTE on a operation and maintenance conference to helicopter pilots and mechanics. Therefore I took it to be true, but who knows, maybe you are right.

  • Now I am really intrigued!!

    Did the conference discuss what aircraft this occured too. Is there a rego so I can look up the NTSB report.

  • I agree. It was also presented to me during training as a LTE incident and it looks every bit of that considering what the wind was described as. Those downwind turns to the right at low airspeed...watch out.

  • @mushatrusha how did u survive and btw is ther anyway to survive a tail rotor failure and if

    necessary is it possible to jump out wit a parachute

  • @danielpilot95 would you jump out with spinning blades above and behind you? cause i wouldn't. best case, ride it out

  • @obese1konobe  As stated, it is LTE...briefed by Bell factory pilot. Airspeed was too low with the high power demand, hence the LTE.

  • @obese1konobe  How can you tell what the airspeed is in that right turn?

  • Comment removed

  • Comment removed

  • There was no indication of a tail-strike, and unless its a tail rotor mechanical (doesnt sound like it) safe to say its pilot error.

    He was at a safe height initially, but descended closer toward the angled plateau. If Im correct in what Ive written below, then by 0:23 sec, he was screwed. But with an additional 100ft, he may have been quite safe, perhaps not affected at all!

    Cause; complacency, and/or bad judgment, and/or inexperience.

  • What really happened? Firstly it occurred just past the cliff while traversing the plateau. A wind coming up and over the cliff face would tumble over and down onto the plateau increasing main rotor in-flow angle and loss of lift.

    In sequence;

    1. Abrupt inflow change.

    2. Pilot compensated with collective, and possibly used up available torque in arresting it, maybe ran out of pedal movement also; LTE scenario (Altitude/Over-Torque type LTE).

    3. Insufficient height/time for effective recovery.

  • Listen to the audio, all the information you need is right there.

    In sequence;

    1. Hear - Normal translational lift up to 0:25.

    2. Hear - Blade pitch change at exactly 0:26, thats not loss of translational lift, thats inflow dropping the relative wind angle (AoA).

    3. Hear - Rpm droop between 0:28 to 0:31 means heaps of collective being applied and new underpants reqd.

  • The more interesting question is whether LTE is always due to pilot error. Helo pilots know the situations where LTE can occur, such as hovering with lots of power in a strong tailwind, and need to avoid them at all costs. A careful pilot will not let himself get into a situation where LTE might develop.

  • I'm just now seeing these comments on the video I posted. If you check out the other videos I posted you'll find a visual example of a simmilar situation as the one nais very clearly explained.

    Suprafrase, yes there are ways to prevent and recover from these situations, but I will leave it for nais to explain them. He'll do it much better than I can.

  • is there a way to combat and prevent that or perhaps recover a helicopter in that situation

  • LTE is not the same as tail rotor failure, although is some or most instances feels the same. As stated earlier posts.. its exact same effect as settling with power (vortex ring state) in the main rotor.. The Tail rotor's thrust, or vorteces, are being pushed back into itself, causing the tail rotor to try and operate in a washing machine or turbulent air. The Tourque of the main rotor (or lack there of if reducing power) causes an uncommanded Yaw! Further it gets out of control, worse it gets!

  • wats LTE?

  • LTE is Loss of tail rotor effectiveness, it is a condition where the tail rotor thrust can't oppose the yaw produced from the main rotor due to a few possible reasons.. One of the most common is a vortex ring state situation, where the airframe yaw stability is lost due to the horizontal stabilizer becoming erroneous when the aircraft slows for landing, loss of translational lift demands more power on landing and the mix of slow airspeed and increased power presented in a turbulent environment

  • become a perfect situation for vortex ring state (also known as settling with power). The tail rotor begins to yaw so fast that it "recycles" its own thrust.. greatly decreasing total thrust pruduced by the tail rotor. Therefore the "Loss of tail rotor effectiveness.

    This is one possible cause of an accident like this, but it's impossible to tell unless you were there.

  • Are you a pilot? or are you like I was before I became a pilot, and just know more than any normal person should haha, I was certainly the helicopter nerd in my platoon haha

  • Nice demonstration of knowledge! I am impressed!

  • @nais26 Oh. Now in English please :)

  • @nais26 You know your stuff.

  • @nais26 Still another name for death.

  • @nais26 Thanks for that comment, interesting. I'm not quite clear on the loss of tail rotor command: So is it only the 'bleed' of power (due to landing power increase) ? How does the 'vortex ring' part work? Is this the main rotor down wash interfering with the tail rotor thrust projection? Doesn't the horizontal stabiliser help with pitch not yaw? Cheers

  • @Deinacrida No probs mate, basically in the event of a LTE, theres a few different nasties that can affect how the tail rotor works, whether that be mechanical or an effect of how the outside forces can change in different circumstances during flight. But as a main rotor can lose effectiveness due to VRS during flight, so can a tail rotor. In gusty conditions wind gusts can travel through the tail rotor in the direction of thrust causing a VRS situation if the heli is moving too slow

  • @Deinacrida I stated that horizontal stabilizers lose authority and you're right, it's the vertical stabilizers that do, not horizontal, I don't know what I was smoking that day, i was probably reading something else while I was writing. But their loss of effectiveness in hover or low airspeed can accelerate the yaw, increasing the speed of the tail rotor VRS situation. This is when there is a total loss of effectiveness. Notice theres no loss of control, but control effectiveness.

  • @Deinacrida Everything control wise is mechanically sound, but it doesn't effectively do what it should. As far as a loss of translational lift is concerned, at low airspeed or in hover (anything below translational lift) you need more power as the effectiveness of airflow over the disc is reduced. So more power pulled means more torque between the main rotor and airframe, which needs more pitch on the tail rotor to counteract it, which means more chance for tailrotor VRS.

  • How does LTE happen?Its not the same as tail rotor failure is it?

  • Loss of Tail rotor effectivness. that sucks

  • LTE

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