Bell 429 crash in China
Agree with AC and DT - just a poor piece of piloting and decision making. Who could have envisaged performance problems on a mountain site at just below MAUM? And in an aircraft known to have TR performance issues! I can't believe he didn't throw the approach away far sooner but at least he is still around to tell the tale - more by luck then judgement!
Back to the 429 accident - looks like a TR control issue - stuck pedal type scenario - since the yaw is affected markedly by airspeed. Could be a physical restriction in the yaw controls or a thrust bearing or a TRGB mounting problem.
Back to the 429 accident - looks like a TR control issue - stuck pedal type scenario - since the yaw is affected markedly by airspeed. Could be a physical restriction in the yaw controls or a thrust bearing or a TRGB mounting problem.
Let’s use another wording, instead of
LTE - loss of tailrotor effectiveness
let us use
RTRA - reduced tailrotor authority 😉
reduced can be anything from a little to nothing left 😉
Hmm, or we have to come up with another wording, cause the problem can also arouse with NOTAR
added weight resulted in not enough authority left....
similarities, altitude, weight....
LTE - loss of tailrotor effectiveness
let us use
RTRA - reduced tailrotor authority 😉
reduced can be anything from a little to nothing left 😉
Hmm, or we have to come up with another wording, cause the problem can also arouse with NOTAR
similarities, altitude, weight....
"Reduced Tail Rotor Authority" or just simply "Running out of tail rotor"?
Don't confuse a poor technique with some real or imaginary series of unavoidable events. Perhaps I am just lucky, having flown for 45 years and 15000 hrs, of which over 8000 were in that pesky 206, and never ran out of pedal. Always was aware of where my feet were, the rate at which that left foot was moving forward, the position of the collective, the power available, if any, the relative winds, and always keeping an escape path to fly away. LTE is horsefeathers. An invention to cover a lack of tail rotor power from the design stage. Despite what some FAA publication says, it is horsefeathers. Remember that those same publications tell you that "gyroscopic effect" is real, that "flapping to equality" is happening in forward flight, and that there is a "ground cushion" of higher pressure under the rotor in the ground hover.
All designed to allow the most rockape of student to understand his rockape instructor who only has 100 hours more than he does, and to grasp some basic concepts.
Don't confuse a poor technique with some real or imaginary series of unavoidable events. Perhaps I am just lucky, having flown for 45 years and 15000 hrs, of which over 8000 were in that pesky 206, and never ran out of pedal. Always was aware of where my feet were, the rate at which that left foot was moving forward, the position of the collective, the power available, if any, the relative winds, and always keeping an escape path to fly away. LTE is horsefeathers. An invention to cover a lack of tail rotor power from the design stage. Despite what some FAA publication says, it is horsefeathers. Remember that those same publications tell you that "gyroscopic effect" is real, that "flapping to equality" is happening in forward flight, and that there is a "ground cushion" of higher pressure under the rotor in the ground hover.
All designed to allow the most rockape of student to understand his rockape instructor who only has 100 hours more than he does, and to grasp some basic concepts.
LTE is horsefeathers. An invention to cover a lack of tail rotor power from the design stage.
Sometimes pprune fishing can take a while...sometimes not so long!
As is being said.....be very careful when saying "LTE" as it might be caused by something other than the other and thus it is not "LTE" per se.
Brother Lappos was very clear in his discussion of the issue.
Here is an archived exchange including Brother Lappos.
Please note he does include "all" single rotor helicopters.
https://yarchive.net/air/loss_of_tai...ctiveness.html
On a less serious note....
Last edited by SASless; 2nd Aug 2018 at 11:55.
Txs for the link.
interesting reading.
With no experience on the 429, just looking through the numbers of tailrotor diameter and all up mass, is it comparable with the 206 in tailrotor authority? (more than double the mass of a 206 with nearly the same diameter, but 4 instead of 2 tailtotorblades.)
interesting reading.
With no experience on the 429, just looking through the numbers of tailrotor diameter and all up mass, is it comparable with the 206 in tailrotor authority? (more than double the mass of a 206 with nearly the same diameter, but 4 instead of 2 tailtotorblades.)
Part of what Nick has to say about the issue has to do with Certification Requirements...and Demonstrated Cross Wind capability.
That in turn determines the parameters that must be met when operating the aircraft.
Unless the Tail Rotor has a surplus of thrust in excess of that required to meet the Certification Requirements then Tail Rotor Control issues might arise if the aircraft encounters situations beyond the envelope the Certification approved.
That in turn determines the parameters that must be met when operating the aircraft.
Unless the Tail Rotor has a surplus of thrust in excess of that required to meet the Certification Requirements then Tail Rotor Control issues might arise if the aircraft encounters situations beyond the envelope the Certification approved.
I didn't following the Nick Lappos reasoning. My way of thinking, if you need to baby the helicopter because the tail rotor margin is what it is, well, baby it. And if you don't baby it and you get stung because of it, well, to me, blame that on the pilot. Don't blame it on the design, and don't solve the problem by using a helicopter with better design (unless of course it's practicable to do that). You just have to use the tools you are given, in such a way as to remain within the safety margin. Using as much baby as you need to.
What part of poorly constructed Certification Criteria do you not understand?
Should we continue to live with plastic fuel tanks knowing they are not crashworthy and incur needless death and maiming as a result.....or do we as we learn....improve the Certification Criteria (using a much simpler but analogous example for you)?
Should we continue to live with plastic fuel tanks knowing they are not crashworthy and incur needless death and maiming as a result.....or do we as we learn....improve the Certification Criteria (using a much simpler but analogous example for you)?
Gullibell - if you fly your helicopter outside its certification limits or RFM and you get LTE, you can blame the pilot - if you fly it within the RFM and certification and get LTE, you can blame the aircraft.
@gullibell,
accidents happen, cause there is a chain of events, failures.
If you need to nurse a helicopter cause it was designed so, every unexpected gust can lead to desaster, cause you’re already operating at the edge of its envelope.
With a proper safety margin from design, even a unintended excursion outside the envelope would only scratch your pride but won‘t take your live.
and I can tell you, once you‘ve operated a powerful machine and have felt the advantages, you won‘t like to go back to a bird you have to nurse to get things done!
accidents happen, cause there is a chain of events, failures.
If you need to nurse a helicopter cause it was designed so, every unexpected gust can lead to desaster, cause you’re already operating at the edge of its envelope.
With a proper safety margin from design, even a unintended excursion outside the envelope would only scratch your pride but won‘t take your live.
and I can tell you, once you‘ve operated a powerful machine and have felt the advantages, you won‘t like to go back to a bird you have to nurse to get things done!
Yeah, right. It is China. Loss of face. They will find any excuse to pin it on somebody other than the person sitting in the pilot seat.
The problem comes when something happens that is not in the script.
All in all the fact that she and the passengers survived should be applauded.
Originally Posted by [email protected]
Gullibell - if you fly your helicopter outside its certification limits or RFM and you get LTE, you can blame the pilot - if you fly it within the RFM and certification and get LTE, you can blame the aircraft.
You can't always blame the aircraft, even within its limits.
It is fair to say that perhaps some aircraft are more crashable than others, but when there is a warning on the tin should you blame the designers? (Robinson's being the exception to the rule)
Bellringer - we had a few incidents that were put down to Fenestron Stall - a condition that didn't exist and Aerospatiale proved it. Not a design issue, just a lack of awareness about the handling characteristics of a Fenestron equipped aircraft.
I should have qualified my earlier comment with 'as long as you don't fly it like a drongo;
I should have qualified my earlier comment with 'as long as you don't fly it like a drongo;
Txs for the link.
interesting reading.
With no experience on the 429, just looking through the numbers of tailrotor diameter and all up mass, is it comparable with the 206 in tailrotor authority? (more than double the mass of a 206 with nearly the same diameter, but 4 instead of 2 tailtotorblades.)
interesting reading.
With no experience on the 429, just looking through the numbers of tailrotor diameter and all up mass, is it comparable with the 206 in tailrotor authority? (more than double the mass of a 206 with nearly the same diameter, but 4 instead of 2 tailtotorblades.)
If I'm doing high altitude heavy sling loads to mountain tops in a 206 (or 212, or whatever helicopter), I nurse it in sensible ways so the unexpected does not lead to disasters. And it's real simple, slow down to a speed that maintains stable load in flight, keep it pointed outside the critical wind azimuth on arrival, keep the NR at 100, keep the sink rate near zero, keep the apparent closure rate until you have arrived where you need to put it. And if you can break the loads up into lighter sorties, do it. We all know these things. Short of the donk stopping at the perfectly wrong time, which would be a disaster, nursing a helicopter so it can safely complete a task is just basic operational airmanship.
If I'm doing high altitude heavy sling loads to mountain tops in a 206 (or 212, or whatever helicopter), I nurse it in sensible ways so the unexpected does not lead to disasters. And it's real simple, slow down to a speed that maintains stable load in flight, keep it pointed outside the critical wind azimuth on arrival, keep the NR at 100, keep the sink rate near zero, keep the apparent closure rate until you have arrived where you need to put it. And if you can break the loads up into lighter sorties, do it. We all know these things. Short of the donk stopping at the perfectly wrong time, which would be a disaster, nursing a helicopter so it can safely complete a task is just basic operational airmanship.
you don’t catch the point.
Sure you can baby a helicopter, like most of us do or have done.
Itˋs the question of reserves available, when the last chainlink tries to spoil your day.
May be the lack of scan, cause a flu is on its way and you missed the creeping in decendrate, the f... big bird which surprises you and you instinctively try to avoid, the gust you haven’t anticipated or the fool, who hasn’t seen you and flies over you giving you just an extra bit of downwash to play with.
Thatˋs when reserves, pulling power AND having tailrotor authority, comes in handy.
As long as you stay lucky through your career, everything seems ok. It´s interesting, when luck isˋt with you all the time.
