First off, thanks everyone for your interest and input in this - these discussions are why a lot of my non-flying (or fixing, or ground-schooling) hours are spent on-line!
OK so here's where we are (or I am, anyway):
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Nick Lappos:
Most LTE's are due to rotor rpm drooping when too much power is commanded. Lowering the rpm reduces the available tail rotor authority, and is really not LTE, but rather over-pitching, a good British term.
LTE is... <snip> ...how a helicopter can lose control while within its normal envelope. In contrast, if a pilot takes on an excessive crosswind (beyond the flight manual limits) or is he pulls too much torque or operates at too much gross weight or pulls the rotor rpm down below normal, the resulting loss of yaw control is not really LTE, it is LTA.
It is not LTE if you don't use the pedal all the way, it is "shy pilot".
helmet fire:
LTE refers to what is thought to be an ingestion of main or tail rotor vorticey through the tail rotor which causes an onset of yaw in the direction induced by torque that cannot be overcome by the application of full "power pedal".
There is a real difference between LTE and rotor drooped LTA... ...let me assure you, LTE does exist.
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So let me make sure I've got this. LTE is when you get a yaw when everything else is OK. It's NOT when M/R torque overcomes T/R thrust - that would be LTA.
So we get LTE because of a disturbance in airflow, then the yaw starts, and only when when we can't stop it with full pedal it's LTA?
(BTW, I'm not sure when the topic of loss of thrust (as in something breaks) or loss of pitch control (stuck pedal/busted linkage) got mixed into this - certainly it wasn't in anything I posted. I realize that you would react differently if the T/R stopped turning or the pedals no longer controlled T/R pitch.)
Bottom line, I am actually concerned enough to be asking for clarity from you guys on a few things:
1) Is the basic FAA description of LTE correct - as a definition of LTE ("LTE is a critical low-speed aerodynamic flight characteristic which can result in an uncommanded rapid yaw rate which does not subside of its own accord and, if not corrected, can result in the loss of aircraft control.")? IOW, the aircraft yaws while in a "normal" flight envelope, and if the pilot doesn't respond properly, the yaw can go out of control.
2) LTA is when full (power) pedal won't arrest a yaw? This could be due to any number of reasons, including low RPM, high density altitude, high gross weight, big crosswind, OR an undersized/underpowered tail rotor.
3) For LTE to become an emergency, does it have to become LTA? I would think so, or else you would arrest the yaw, at which point you are no longer experiencing LTE or LTA. If the Bell issue is due to an undersized/underpowered T/R, I would think it would also be more susceptable to LTA, which is the real emergency.
4) If 1) is true, are you then more susceptable to LTE (or can non-Bell helicopters become susceptable to LTE) if operating near or beyond the edges of the flight envelope as described in 2? Or is it simply that ALL helicopters become more susceptable to LTA, but Bell helicopters have the additional gremlin of LTE which increases the chances of LTA?
5) Since the FAA doesn't single out make/model, is it fair to allow a student to go to a checkride with the following: all helicopters are susceptable to LTA if you push things enough. The "phenomenom" of LTE is the susceptability of a helicopter to enter a uncommanded rapid yaw while still in a "normal" envelope - while all helicopters are susceptable to uncommanded yaw, certain makes/models will yaw earlier, faster and further than others. Certain makes/models can also experience LTA while in a normal envelope. If you experience a rapid uncommanded yaw which then leads you into LTA, the amount of trouble you are in is inversely related to your altitude, but it is trouble no matter what.