AS350 Astar / AS355 Twinstar [Archive Copy]
Join Date: Dec 2003
Location: An t- Eilean
Posts: 20
Likes: 0
Received 0 Likes
on
0 Posts
How much is this going to cost me..
Who or what is the best thing to use to get accurate operating costings for UK aircraft? Is there anything like C&D or who are the best to speak to? The a/c concerned is an AS350B2.
Any advice from them older and wiser greatly appreciated.
Any advice from them older and wiser greatly appreciated.
I operate a BA and all i can tell you is...............A LOT !!! About double that at least of a 206 , and when it comes to the engine side.....well you are bent over and R****ed by Turbomeca....circa £200,000 if you are unfortunate enough to have FOD damage and have to have an exchange !! I can buy around 7or8 allison C20 engines for that. I cannot imagine a B2 will be much different.........great machine though!
Join Date: Mar 2003
Location: JAA land
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
LTE with AS 350?
Just confrontated with an AS 350 BA accident i'm interested if anybody of you guys have experienced a LTE on a AS 350. I have a few hundred hours on this type of helicopter but never encountered such a problem.
The ship was taking off with an external load on a 50ft rope when suddenly in 100ft it began to spin to the left. At this moment the IAS should be round about 10-20kt. There is no indication of any technical malfunction. The helicopter was short before the MTOW but not overloaded.
LTE would declare the reactions of the ship seen by the witnesses.
The ship was taking off with an external load on a 50ft rope when suddenly in 100ft it began to spin to the left. At this moment the IAS should be round about 10-20kt. There is no indication of any technical malfunction. The helicopter was short before the MTOW but not overloaded.
LTE would declare the reactions of the ship seen by the witnesses.
Join Date: Jun 2002
Location: 1 deg south, avoiding Malaria P Falciparium
Posts: 385
Likes: 0
Received 0 Likes
on
0 Posts
the As350 has tremendus t/r authority but altitude and high Gross Weights you can get your self in real trouble.
I had a 350B2 swap ends on me picking a sling load at nearly 10K. The load wasnt that heavy. light and varible winds 0-5 from every where. I went to pick the load up vertically at 75-100 feet the thing just swapped ends , weather vained into the wind and stopped. My heart went in to my mounth and I was nano seconds from punching the load off.
A good friend an someting similar happen on approach to land , near MGW at altitude, real light squirrely winds, shallow approach 10-15 off the ground swapped ends and stopped.
I have a heard a few other storys , all at alt near mgw.
hope this helps
RB
I had a 350B2 swap ends on me picking a sling load at nearly 10K. The load wasnt that heavy. light and varible winds 0-5 from every where. I went to pick the load up vertically at 75-100 feet the thing just swapped ends , weather vained into the wind and stopped. My heart went in to my mounth and I was nano seconds from punching the load off.
A good friend an someting similar happen on approach to land , near MGW at altitude, real light squirrely winds, shallow approach 10-15 off the ground swapped ends and stopped.
I have a heard a few other storys , all at alt near mgw.
hope this helps
RB
Last edited by rotorboy; 3rd Oct 2005 at 15:36.
Gatvol
Join Date: Jun 2000
Location: KLAS/TIST/FAJS/KFAI
Posts: 4,195
Likes: 0
Received 0 Likes
on
0 Posts
The ship was taking off with an external load on a 50ft rope when suddenly in 100ft it began to spin to the left
After you get those, Im sure you will see what makes the world go around............
Join Date: Apr 2003
Location: USA
Age: 75
Posts: 3,012
Likes: 0
Received 0 Likes
on
0 Posts
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. What was the power/rotor rpm during the incident?
Join Date: May 2001
Location: queensland australia
Age: 77
Posts: 563
Likes: 0
Received 1 Like
on
1 Post
thank you nick, thank you,
overpitching at last, instead of more of this crap about lte.
obviously if you run out of main rotor rpm you will lose tail rotor effectiveness. if the wind changes speed you get loss of tailrotor effectivness.
the chance of weather cocking with a heavy load load at altitude is to be totally expected and not a consequence of lte but a case of no more power available, something has to give.
i know why pilots like to think lte was to blame, it's because it is a good excuse for bad handling or inattentiveness.
better than telling the boss that you overpitched his machine and bent it.
"it had nothing to do with me boss", "it was that bloody lte phenomena", or "I could still pull pitch so i must of had more power left, then it started spinning all by itself".
thanks again nick for the reality check.
overpitching at last, instead of more of this crap about lte.
obviously if you run out of main rotor rpm you will lose tail rotor effectiveness. if the wind changes speed you get loss of tailrotor effectivness.
the chance of weather cocking with a heavy load load at altitude is to be totally expected and not a consequence of lte but a case of no more power available, something has to give.
i know why pilots like to think lte was to blame, it's because it is a good excuse for bad handling or inattentiveness.
better than telling the boss that you overpitched his machine and bent it.
"it had nothing to do with me boss", "it was that bloody lte phenomena", or "I could still pull pitch so i must of had more power left, then it started spinning all by itself".
thanks again nick for the reality check.
Join Date: Jun 2002
Location: 1 deg south, avoiding Malaria P Falciparium
Posts: 385
Likes: 0
Received 0 Likes
on
0 Posts
Imabell,
or perpahs direction.
Ok explain to me your deffenition of LTE.
When you have a light varaible wind, you position into the current/ most prevenlant wind direction, then wind shift slightly and you are at a high power setting and you "weathercock" or have an uncommanded yaw. Recoverable or not, how is that not a symptom or byproduct of LTE?
So all these 206 accidents at altitude with uncommanded yaw on short final to spots are all over pitching? not lte? Tailrotor authority has nothing to do with it?
rb
if the wind changes speed you get loss of tailrotor effectivness.
Ok explain to me your deffenition of LTE.
When you have a light varaible wind, you position into the current/ most prevenlant wind direction, then wind shift slightly and you are at a high power setting and you "weathercock" or have an uncommanded yaw. Recoverable or not, how is that not a symptom or byproduct of LTE?
So all these 206 accidents at altitude with uncommanded yaw on short final to spots are all over pitching? not lte? Tailrotor authority has nothing to do with it?
rb
Terminology: the bane of understanding!
Rotorboy, I see your points, but I think you are mixing the terminology between LTE, Authority and perhaps not understanding imabell's oevrpitched call. So we are all singing from the same sheet of music, I suggest the following terminology cut and pasted from another thread:
Loss of tail rotor control: You are not able to control the tail rotor pitch mechanism.
Loss of tail rotor thrust: Little spinning thing at the back stops spinning or falls off.
Loss of tail rotor effectiveness (LTE): "Newly" discovered and named in the 80's after many (in particular OH-58/B206) accidents. Although somewhat awkwardly named (as the tail rotor is still effectively working and must be providing thrust) 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". The yaw rotation can build up quickly enough to fool most pilots into believing they have experienced a loss of tail rotor thrust. The concept has come under fire lately because of the early thoughts that the tail rotor enters vortex ring state being a little hard to prove. Oh - and then there is fenestron stall that possibly fits into this category too, although strongly denied as a possibility by the manufacturer whilst allegedly being strongly experienced by the pilots!
Loss of Tail Rotor Authority (LTA): Also a new term to make the old Huey war story of "..and then I ran out of left pedal and..." sound a little more sophisticated and technical. In this situation, the tail rotor does not produce enough thrust to counteract the torque/crosswind combination you require, your power pedal hits the stop, and around you go - though often quite gently when compared to LTE or loss of thrust. A lot of aircraft are susceptible to this, but the UH-1D/H Huey is famous for it - and many people have had the earth come up and smite them as a result.
This is somewhat semantics, but the reason I used the term Loss of Tail Rotor Authority instead of “Over pitched” is that it confuses the situation a bit. Over pitched infers that the blade pitch angle is too excessive either for the engine power to overcome the induced drag, or that the blade may be in some sort of stall condition. Most commonly, over pitching refers to the main rotor case (as Nick says below) causing a RRPM droop and therefore LTA, or it could mean a T/R blade overpitch causing LTA. Either way, both manifest in a LTA situation - not an LTE.
But not all LTA is caused by over pitching. LTA also covers the other conditions where niether the M/R or T/R blade is over pitched but the T/R still cannot produce enough thrust to counter act the yaw. IE the T/R blade pitch angle is at it's max, but the resultant thrust is insufficient to overcome the yaw conditions caused by power, DA, adverse wind, pilot handling, etc.
So in green thumb's case, I don’t believe that the tail rotor or main rotor has “over pitched”, although as imabell points out, this common term has been clouded by the LTE hysteria, and somewhat forgotten - and with the forgotten term comes a forgotten condition and a forgotten recovery technique - and I share imabell's concern with this. Fly a UH-1H and you will be forced to remember.
In the AS 350 case, though you have yet to provide weight and DA details, I think an LTA case can be made: the T/R was unable to provide enough yaw authority for the power/DA/wind combination. Given that it was an AS 350, it is unlikely that the T/R blade was over pitched/stalled, and unlikely to be a main rotor droop – though the term over pitched certainly describes the aircraft reaction accurately, and the recovery actions are the same. (Unlikely does not mean impossible!)
edited to include corrections by AOTW!
Rotorboy, I see your points, but I think you are mixing the terminology between LTE, Authority and perhaps not understanding imabell's oevrpitched call. So we are all singing from the same sheet of music, I suggest the following terminology cut and pasted from another thread:
Loss of tail rotor control: You are not able to control the tail rotor pitch mechanism.
Loss of tail rotor thrust: Little spinning thing at the back stops spinning or falls off.
Loss of tail rotor effectiveness (LTE): "Newly" discovered and named in the 80's after many (in particular OH-58/B206) accidents. Although somewhat awkwardly named (as the tail rotor is still effectively working and must be providing thrust) 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". The yaw rotation can build up quickly enough to fool most pilots into believing they have experienced a loss of tail rotor thrust. The concept has come under fire lately because of the early thoughts that the tail rotor enters vortex ring state being a little hard to prove. Oh - and then there is fenestron stall that possibly fits into this category too, although strongly denied as a possibility by the manufacturer whilst allegedly being strongly experienced by the pilots!
Loss of Tail Rotor Authority (LTA): Also a new term to make the old Huey war story of "..and then I ran out of left pedal and..." sound a little more sophisticated and technical. In this situation, the tail rotor does not produce enough thrust to counteract the torque/crosswind combination you require, your power pedal hits the stop, and around you go - though often quite gently when compared to LTE or loss of thrust. A lot of aircraft are susceptible to this, but the UH-1D/H Huey is famous for it - and many people have had the earth come up and smite them as a result.
This is somewhat semantics, but the reason I used the term Loss of Tail Rotor Authority instead of “Over pitched” is that it confuses the situation a bit. Over pitched infers that the blade pitch angle is too excessive either for the engine power to overcome the induced drag, or that the blade may be in some sort of stall condition. Most commonly, over pitching refers to the main rotor case (as Nick says below) causing a RRPM droop and therefore LTA, or it could mean a T/R blade overpitch causing LTA. Either way, both manifest in a LTA situation - not an LTE.
But not all LTA is caused by over pitching. LTA also covers the other conditions where niether the M/R or T/R blade is over pitched but the T/R still cannot produce enough thrust to counter act the yaw. IE the T/R blade pitch angle is at it's max, but the resultant thrust is insufficient to overcome the yaw conditions caused by power, DA, adverse wind, pilot handling, etc.
So in green thumb's case, I don’t believe that the tail rotor or main rotor has “over pitched”, although as imabell points out, this common term has been clouded by the LTE hysteria, and somewhat forgotten - and with the forgotten term comes a forgotten condition and a forgotten recovery technique - and I share imabell's concern with this. Fly a UH-1H and you will be forced to remember.
In the AS 350 case, though you have yet to provide weight and DA details, I think an LTA case can be made: the T/R was unable to provide enough yaw authority for the power/DA/wind combination. Given that it was an AS 350, it is unlikely that the T/R blade was over pitched/stalled, and unlikely to be a main rotor droop – though the term over pitched certainly describes the aircraft reaction accurately, and the recovery actions are the same. (Unlikely does not mean impossible!)
edited to include corrections by AOTW!
Last edited by helmet fire; 3rd Oct 2005 at 21:40.
Join Date: Apr 2003
Location: USA
Age: 75
Posts: 3,012
Likes: 0
Received 0 Likes
on
0 Posts
rotorboy,
In an LTE study I did about 7 years ago, based on worldwide accidents of all helos, using four different data bases, this is what it showed:
95% of all LTE accidents involve Bell 206 models.
Virtually 100% of all LTE accidents involve Bell helicopters (one Robbie in UK was reported as LTE, but was probably over pitching).
My conclusion was that the inadequate size of the Bell 206 tail rotor was the principal cause of its LTE woes.
A second finding is that all tail rotor authority events were being called LTE because the marketing campaign conducted by Bell was effective on removing the heat from their design.
LTE really does not exist, it is a label used to blame the pilot when a marginal helicopter loses yaw control within its approved envelope. That does not mean that a 206 can be milked by an experienced pilot to not lose tail authority.
LTE cannot be experienced by any helo built to modern standards (larger tail rotor). It is impossible to get LTE in a Black Hawk, Apache, S76, H-500, EH-101, Lynx, etc because they have adequate tail rotors.
In an LTE study I did about 7 years ago, based on worldwide accidents of all helos, using four different data bases, this is what it showed:
95% of all LTE accidents involve Bell 206 models.
Virtually 100% of all LTE accidents involve Bell helicopters (one Robbie in UK was reported as LTE, but was probably over pitching).
My conclusion was that the inadequate size of the Bell 206 tail rotor was the principal cause of its LTE woes.
A second finding is that all tail rotor authority events were being called LTE because the marketing campaign conducted by Bell was effective on removing the heat from their design.
LTE really does not exist, it is a label used to blame the pilot when a marginal helicopter loses yaw control within its approved envelope. That does not mean that a 206 can be milked by an experienced pilot to not lose tail authority.
LTE cannot be experienced by any helo built to modern standards (larger tail rotor). It is impossible to get LTE in a Black Hawk, Apache, S76, H-500, EH-101, Lynx, etc because they have adequate tail rotors.
Overpitching (as I understand the term anyway) is when you pull too much collective for your engine's available power to overcome the drag, so the rotor system slows down; it doesn't necessarily imply a stall (even though I guess you could say that bits of the blade are stalled all the time). The only way to recover would be to lower the collective.
What I'm getting at is that in an 'overpitched' situation you'd have drooping Nr and the associated loss of main and tail rotor thrust, not necessarily the case in these so-called LTE situations.
As you say, helmet fire, the 206 LTE situation as we have had it explained to us is a rapid onset yaw probably caused by vortex ingestion.
I think that tends to support the Huey 'running out of left pedal' case being different to that, because you can sit there in the hover with the pedal bouncing off the stops but not be scared of whipping around to the right at a great rate - it feels controllable, while not necessarily comfortable.
What I'm getting at is that in an 'overpitched' situation you'd have drooping Nr and the associated loss of main and tail rotor thrust, not necessarily the case in these so-called LTE situations.
As you say, helmet fire, the 206 LTE situation as we have had it explained to us is a rapid onset yaw probably caused by vortex ingestion.
I think that tends to support the Huey 'running out of left pedal' case being different to that, because you can sit there in the hover with the pedal bouncing off the stops but not be scared of whipping around to the right at a great rate - it feels controllable, while not necessarily comfortable.
Join Date: May 2001
Location: queensland australia
Age: 77
Posts: 563
Likes: 0
Received 1 Like
on
1 Post
thanks again nick, "lte does not exist".
but its not a way to blame the pilot it's a way for the pilot to move the blame to the helicopter.
only ' thought' to happen to the bell 206.
and your right too arm out the window, when you demand more power than any helicopter engine (piston included) can supply you end up with full left pedal and no tail rotor authority, ergo loss of tail rotor effectiveness.
fly the aircraft properly and it won't happen.
but its not a way to blame the pilot it's a way for the pilot to move the blame to the helicopter.
only ' thought' to happen to the bell 206.
and your right too arm out the window, when you demand more power than any helicopter engine (piston included) can supply you end up with full left pedal and no tail rotor authority, ergo loss of tail rotor effectiveness.
fly the aircraft properly and it won't happen.
Join Date: Mar 2003
Location: JAA land
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for your answers. I will try to describe the accident better.
An AS 350 BA (converted from "B") hauling loads with a 50ft rope in 3000ft PA, OAT 20°C, light and variable wind. Take off weight seems to be round about 1950-2100kg. (the load is destroyed and it's not possible to determine the weight of the load exactly) The >5000h experienced pilot lifted the load without problems and began to climb and to accelerate when suddenly the ship turns to the left. The left spin accelerated and wasn't to stop, even not with lowering the collective or full right pedal the pilot later explained. The ship and the load turned around the heads of the ground crew some full 360's and chrashed 50m ahead into the ground. The pilot doesn't opened the hook and released the load because he afraid to hurt someone on the ground.
As i wrote before there are no indications of a technical malfunction. The experienced ground crew reported the tail rotor was turning all the time. I' m surprised because the whole thing seems to me to be a kind of loss of directional control. That's not easy to understand because i thought LTE is a problem of the 206 or 500 series. Of course a loss of directional control is also possible on a AS350, but i have never heard about such a problem on AS 350 and never experienced personally on this type of helicopter. But i believe the pilot is really experienced on this kind of work, doing such flights a lot of years and will not loose the a/c out of control on such a "simple" flight during accelerating. But we are all humans and nothing is impossible.
Good to say the pilot isn't to bad injured and we all hope he will made a good and fast recovery.
An AS 350 BA (converted from "B") hauling loads with a 50ft rope in 3000ft PA, OAT 20°C, light and variable wind. Take off weight seems to be round about 1950-2100kg. (the load is destroyed and it's not possible to determine the weight of the load exactly) The >5000h experienced pilot lifted the load without problems and began to climb and to accelerate when suddenly the ship turns to the left. The left spin accelerated and wasn't to stop, even not with lowering the collective or full right pedal the pilot later explained. The ship and the load turned around the heads of the ground crew some full 360's and chrashed 50m ahead into the ground. The pilot doesn't opened the hook and released the load because he afraid to hurt someone on the ground.
As i wrote before there are no indications of a technical malfunction. The experienced ground crew reported the tail rotor was turning all the time. I' m surprised because the whole thing seems to me to be a kind of loss of directional control. That's not easy to understand because i thought LTE is a problem of the 206 or 500 series. Of course a loss of directional control is also possible on a AS350, but i have never heard about such a problem on AS 350 and never experienced personally on this type of helicopter. But i believe the pilot is really experienced on this kind of work, doing such flights a lot of years and will not loose the a/c out of control on such a "simple" flight during accelerating. But we are all humans and nothing is impossible.
Good to say the pilot isn't to bad injured and we all hope he will made a good and fast recovery.
Last edited by greenthumb; 4th Oct 2005 at 07:43.
Join Date: Jul 2002
Location: Denver, CO and the GOM
Age: 63
Posts: 515
Likes: 0
Received 0 Likes
on
0 Posts
Would it be better to explain the "overpitch vs LTE" in this fashion?
It takes a fixed amount of horsepower to keep a helicopter hovering. For any horsepower, as RRPM goes down, torque (as expressed about the rotor mast) goes up. This demands more thrust from the tail rotor to maintain heading.
At the same time, the tail rotor RPM drops, therefore demanding a greater AOA just to maintain thrust. So you have two factors demanding left pedal, and there's only so much left pedal...
However, for most helicopters, the tail rotor is able to effectively counter any torque the engine/main rotor can develop as long as you keep the RPM in the green (and under most flight conditions). So for most helicopters, "LTE" can only happen if you overpitch, and droop the RPM while pulling a lot of power.
A few helicopters (B206, H269A) can, with RRPM in the (normal) green, regularly produce more torque about the rotor mast than the tail rotor can counter. So even if you are doing nothing "wrong", at high power settings you can find yourself running out of left pedal because the tail rotor is incapable of sufficient thrust even when operating at full RPM.
It takes a fixed amount of horsepower to keep a helicopter hovering. For any horsepower, as RRPM goes down, torque (as expressed about the rotor mast) goes up. This demands more thrust from the tail rotor to maintain heading.
At the same time, the tail rotor RPM drops, therefore demanding a greater AOA just to maintain thrust. So you have two factors demanding left pedal, and there's only so much left pedal...
However, for most helicopters, the tail rotor is able to effectively counter any torque the engine/main rotor can develop as long as you keep the RPM in the green (and under most flight conditions). So for most helicopters, "LTE" can only happen if you overpitch, and droop the RPM while pulling a lot of power.
A few helicopters (B206, H269A) can, with RRPM in the (normal) green, regularly produce more torque about the rotor mast than the tail rotor can counter. So even if you are doing nothing "wrong", at high power settings you can find yourself running out of left pedal because the tail rotor is incapable of sufficient thrust even when operating at full RPM.
Join Date: Apr 2003
Location: USA
Age: 75
Posts: 3,012
Likes: 0
Received 0 Likes
on
0 Posts
Flingwing,
The only quibble I have with your observation is that LTE is the wrong term to use if the overpitch causes LTA.
LTE is the moniker established by Bell to describe how a helicopter can lose control while within its normal envelope (in spite of imabell's statements otherwise). 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.
If we call every loss of yaw control LTE, we blur the reason why it happened, and thus blur the responsibility for who caused it, and also blur the method used to prevent it.
helmet fire's post above slices nicely thru the definitions, and is worthwhile, I think.
To imabell,
Your protests are noted, some people can fly a crummy helicopter and stay out of trouble, I agree, but when 95% of the mishaps are on one model helo, it says that model has a problem. I really dislike blaming the pilot when it is clear otherwise. As a former test pilot, I worked to try and make helos that helped us stay out of trouble.
When the Bell Cobra experienced LTE, the tail rotor was fixed, after an extensive campaign that the Army insisted upon.
When the prototype Bell Kiowa Warrier was flown by Army test pilots, they experienced LTE, and grounded the aircraft to require that the tail rotor be made more powerful.
When 10% of all JetRanger accidents are caused by LTE, Bell published an elaborate procedure that tells you how to baby the aircraft, and how to blame yourself if it happens.
As long as we apologize for our aircraft, we are doomed to have to deal with their shortfalls. When we as a pilot community stop blaming ourselves, we stand a chance at becoming a legitimate transport system. Please stop blaming your brother pilots and start focussing on how to get us better aircraft. Perhaps you could start by changing your username so that your biasses are slightly more hidden!
The only quibble I have with your observation is that LTE is the wrong term to use if the overpitch causes LTA.
LTE is the moniker established by Bell to describe how a helicopter can lose control while within its normal envelope (in spite of imabell's statements otherwise). 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.
If we call every loss of yaw control LTE, we blur the reason why it happened, and thus blur the responsibility for who caused it, and also blur the method used to prevent it.
helmet fire's post above slices nicely thru the definitions, and is worthwhile, I think.
To imabell,
Your protests are noted, some people can fly a crummy helicopter and stay out of trouble, I agree, but when 95% of the mishaps are on one model helo, it says that model has a problem. I really dislike blaming the pilot when it is clear otherwise. As a former test pilot, I worked to try and make helos that helped us stay out of trouble.
When the Bell Cobra experienced LTE, the tail rotor was fixed, after an extensive campaign that the Army insisted upon.
When the prototype Bell Kiowa Warrier was flown by Army test pilots, they experienced LTE, and grounded the aircraft to require that the tail rotor be made more powerful.
When 10% of all JetRanger accidents are caused by LTE, Bell published an elaborate procedure that tells you how to baby the aircraft, and how to blame yourself if it happens.
As long as we apologize for our aircraft, we are doomed to have to deal with their shortfalls. When we as a pilot community stop blaming ourselves, we stand a chance at becoming a legitimate transport system. Please stop blaming your brother pilots and start focussing on how to get us better aircraft. Perhaps you could start by changing your username so that your biasses are slightly more hidden!
Thoroughly agree with Nick here about the procedure on how to baby the aircraft and blame yourself when it all goes wrong! It was the same on the Skycrane thread: LTE is thrown about with such misunderstanding that it has succesfully hidden a design flaw in a shroud of aerodynamic faux-legitimacy! (I think I shoud resume drinking after that phrase - sorry!).
What green thumb describes is most assuredly not LTE, but that is the only one we can rule out from the description thus far. Without more info, we can only rule out LTE, we are left with Loss of tail rotor thrust, Loss of tail rotor control and LTA. We have a high power demand, with adverse wind direction ?? at relatively high DA (approx 4560 ft - plus humidity?) More questions are still required: was there any rotor droop? If so, was this due to N1 limiting, or governor malfunction? If not, was the tail rotor being driven (or just windmilling? The tail rotor was spinning - but was it powered? Were the t/r control mechanisms functioning? Was it a hydraulic event? Sounds like he held the load and crashed the aircraft? Was he able to move the aircraft away from the ground people, but not the load? Did he have the cargo release system active?
And others will bring more to the table I am sure.
What green thumb describes is most assuredly not LTE, but that is the only one we can rule out from the description thus far. Without more info, we can only rule out LTE, we are left with Loss of tail rotor thrust, Loss of tail rotor control and LTA. We have a high power demand, with adverse wind direction ?? at relatively high DA (approx 4560 ft - plus humidity?) More questions are still required: was there any rotor droop? If so, was this due to N1 limiting, or governor malfunction? If not, was the tail rotor being driven (or just windmilling? The tail rotor was spinning - but was it powered? Were the t/r control mechanisms functioning? Was it a hydraulic event? Sounds like he held the load and crashed the aircraft? Was he able to move the aircraft away from the ground people, but not the load? Did he have the cargo release system active?
And others will bring more to the table I am sure.
Join Date: Jul 2002
Location: Denver, CO and the GOM
Age: 63
Posts: 515
Likes: 0
Received 0 Likes
on
0 Posts
Hi Nick,
Yep, I'm just a poor ol' head CFI trying to thread the briar patch between reality and what's printed in the textbooks we still have to answer to come checkride time. Since it was OVC002 all day, I got to engage a couple of my instructors in a discussion of this very subject, trying to find the balance.
We decided that if you get the "uncommanded yaw", you have just that. a yaw. If you react promptly and correctly and stop the yaw, it was not LTE. If the yaw stops on its own, not LTE. However, if you respond promptly and correctly but cannot stop the yaw, you have LTE (this still keeps us safe with the FAA). If you don't respond promptly or correctly, then you goofed - and the result cannot be truely classified as uncommanded (even if the first bit was) - hey you had your chance, Tex.
So if Sammy Schweizer gets his tail pushed around by that 12G20 tailwind, but ends up facing the wind going "wha'happah?", not LTE.
Rebecca Robbie gets sideways on a steep approach but stomps the left pedal and stops things, not LTE.
Joey Jetbanger starts seeing the word go 'round while OGE and downwind, and full left pedal won't stop it, LTE.
I agree that it is not altogether appropriate to call low-RPM induced "unstoppable yaw" LTE, but at that point, it ends up the same - (even if you initially screwed up by drooping the RPM).
Yep, I'm just a poor ol' head CFI trying to thread the briar patch between reality and what's printed in the textbooks we still have to answer to come checkride time. Since it was OVC002 all day, I got to engage a couple of my instructors in a discussion of this very subject, trying to find the balance.
We decided that if you get the "uncommanded yaw", you have just that. a yaw. If you react promptly and correctly and stop the yaw, it was not LTE. If the yaw stops on its own, not LTE. However, if you respond promptly and correctly but cannot stop the yaw, you have LTE (this still keeps us safe with the FAA). If you don't respond promptly or correctly, then you goofed - and the result cannot be truely classified as uncommanded (even if the first bit was) - hey you had your chance, Tex.
So if Sammy Schweizer gets his tail pushed around by that 12G20 tailwind, but ends up facing the wind going "wha'happah?", not LTE.
Rebecca Robbie gets sideways on a steep approach but stomps the left pedal and stops things, not LTE.
Joey Jetbanger starts seeing the word go 'round while OGE and downwind, and full left pedal won't stop it, LTE.
I agree that it is not altogether appropriate to call low-RPM induced "unstoppable yaw" LTE, but at that point, it ends up the same - (even if you initially screwed up by drooping the RPM).
Nice work with the names there Flingwing!
Considering the start point of the thread, you'll have to come up with another one like 'Simone Squirrel' or 'Etienne Ecureil' now - or 'Anatole A-Star' for the Americans.
Considering the start point of the thread, you'll have to come up with another one like 'Simone Squirrel' or 'Etienne Ecureil' now - or 'Anatole A-Star' for the Americans.
wow flingwing - you really an instructor?
wow flingwing - you really an instructor?
I strongly suggest you review those text books with your mates. Perhaps you could quote them here because your conclusions do not match current aerody theory. There is a real difference between LTE and rotor drooped LTA, Loss of control or loss of thrust.
And guess what - they all have different recovery requirements, no matter how much you and your buddies decide it is all so simple.
Smash -
Mate that is not LTE, though let me assure you, LTE does exist. If you are putting in left pedal, that is due to streamlining unloading the T/R by enabling the vertical fin to provide some thrust and translational lift reducing inducd power, nothing to do with LTE, LTA, etc. The T/R is working too well, not well enough. Call it translational lift.
wow flingwing - you really an instructor?
I strongly suggest you review those text books with your mates. Perhaps you could quote them here because your conclusions do not match current aerody theory. There is a real difference between LTE and rotor drooped LTA, Loss of control or loss of thrust.
And guess what - they all have different recovery requirements, no matter how much you and your buddies decide it is all so simple.
Smash -
Mate that is not LTE, though let me assure you, LTE does exist. If you are putting in left pedal, that is due to streamlining unloading the T/R by enabling the vertical fin to provide some thrust and translational lift reducing inducd power, nothing to do with LTE, LTA, etc. The T/R is working too well, not well enough. Call it translational lift.