Chas Sheriff's 407 Mishap

[Snowbound 612]

Mishap was 1 Aug. Should he have been able to run this one on.

Charleston Sheriff's helicopter missing parts when it crashed, preliminary report says | News | postandcourier.com (https://www.postandcourier.com/news/charleston-sheriffs-helicopter-missing-parts-when-it-crashed-preliminary-report-says/article_7a48a09e-3b91-11ee-b290-0b47abf875fb.html)
www.postandcourier.com/news/video-of-charleston-sheriff-helicopter-released/article_f77dd626-32fc-11ee-a044-2b0374348f9a.html

[Hueymeister]

I hope he bought a lottery ticket...lucky son of a gun...

[Snowbound 612]

Airport is the civillian side of Charleston AFB. Sumter airport is a short flight. Less than an hour.

[SASless]

Lots of questions begged (based upon the extremely detailed news article and its quoted sources) that might bear answering at some point in the future when the Lawyers get to nosing around in the feed trough.

I would love to be a bug on wall when the various folks get quizzed upon their actions that had a bearing upon the event.

[[email protected]]

It is amazing he survived that - it was a proper crash!

I wonder if he just let the airspeed drop off a little too much on his approach - ground rush tends to do that to pilots - but his subsequent reaction should have been to go around carefully and reposition for another attempt rather than end up in almost a high hover running out of ideas

Wonder how much TR control/failure training he had done.

[heliduck]

A good pre-flight inspection will prevent most crashes, after “routine maintenance” I struggle to understand why you wouldn’t put your fingers on every bolt/nut that was tampered with!

[OvertHawk]

A good pre-flight inspection will prevent most crashes, after “routine maintenance” I struggle to understand why you wouldn’t put your fingers on every bolt/nut that was tampered with!

You can certainly have a good look at what has been worked on but there is no way that you can see or access all the nuts, bolts and other components that may have been worked on by engineers. You have to trust them and that is why critical components require duplicate inspections after they have been worked on.

If there was an engineering error in this case then the individuals, systems and working practices need to be investigated to find out where it went wrong.

[60FltMech]

I suppose the original poster thought the better of his post(hopefully) or the moderators took it down(thankfully), but I saw it and feel the sentiment he expressed needs addressed.

The gist of the now deleted post was “from my experience, some country bumpkin mechanic was probably responsible for this accident in this backwater airport”

I grant that the original poster may have a strongly held opinion based on experience that informs his opinion of the southern United States. However, as we should all know by now, Human Factors accidents know no geographical, cultural, political etc boundaries. Humans are humans everywhere, and as long as we are in the chain, we can mess up, no matter how sophisticated we may think we are.

As humans we all fall victim to our own feelings of superiority, I know I surely was when I composed what I was originally going to say regarding that now deleted post!

But that stuff doesn’t do anybody any good. The facts are, somebody(possibly more than one) made a great big mistake that will possibly cost them their job and that nearly cost somebody their life, regardless of how well/poorly they did their job up til this point.

The only thing I know about this incident, as a mechanic who also flies as a crewmember: I don’t ever want to feel what either one of those individuals is feeling right now.

And I don’t ever want to be so arrogant that I believe that it can’t happen to me.

FltMech

[FH1100 Pilot]

It's easy to armchair-quarterback any accident. Pompous pilots say, "Well, what *I* would have done..." or "What he should have done..." Yeah, yeah...you weren't in the cockpit with him, so shut up. It's a tough situation when the aircraft does not do what you want it to do. Adrenaline starts pumping. It's hard to be as cool and calm as a test pilot, and we tend to want to just get the dang thing on the ground because we don't know what *else* is going to go wrong. The 407 did have a history of tail rotor problems.

The pilot reported that it felt like the pedals weren't connected to anything, indicating a loss of t/r pitch control. So, not a complete loss of thrust, but a "stuck pedal" situation. The report says that of the *two* levers that control the tail rotor, one was disconnected and the other was loose. Are they referring to the "dogbone" pitch-change links? If so, a running landing would have been called for, and that's what it looks like he was attempting. But it went "pear-shaped" as our British friends like to say. Oh well, we can't all be Yeager. The pilot is alive and I'm sure Bell will happily sell them a new 407.

But I'm curious. If it *was* one of the p/c dogbone links that became disconnected... Hmm. That would mean that the hardware securing the p/c links must have been both loose and unsaftied. I have to ask the uncomfortable question: Could that not have been caught on preflight? And, more importantly, would *I* have caught it on preflight?

[[email protected]]

It's a tough situation when the aircraft does not do what you want it to do. Adrenaline starts pumping. It's hard to be as cool and calm as a test pilot, and we tend to want to just get the dang thing on the ground because we don't know what *else* is going to go wrong. The 407 did have a history of tail rotor problems.
That's where the training comes in and why I wondered how much, if any, he had done.

If you have never trained for such a scenario then you will be poorly placed - and most likely panic if it doesn't go right as per the video.

If you have trained for it, there is no guarantee you will get it safely on the ground but you stand a far higher chance of applying some basic techniques to maximise your chance of survival.

​​​​​​​If you have no idea how to deal with TR malfunctions, you really shouldn't have a licence.

[wrench1]

If the NTSB report's (https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/192772/pdf) nomenclatures are close or correct, there is one "lever" that could cause complete loss of T/R control and be associated with a scheduled inspection task. The lever (walking beam) is located in the aft hatrack area where the TR servo attaches on one end and the TR long control tube on the other. And is not visible at all once the aircraft is closed up.

And just to reiterate what FltMech said: It can happen to anyone regardless of skill, experience, and even 135/121 ops with all the rules. Nothing worse than the gut punch you feel when something like this happens from a maintenance perspective.

[FH1100 Pilot]

If the NTSB report's (https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/192772/pdf) nomenclatures are close or correct, there is one "lever" that could cause complete loss of T/R control and be associated with a scheduled inspection task. The lever (walking beam) is located in the aft hatrack area where the TR servo attaches on one end and the TR long control tube on the other. And is not visible at all once the aircraft is closed up.
That certainly would give the pilot an indication that the pedals weren't hooked up - they wouldn't be! But... "Inspectors with the Federal Aviation Administration who responded to the crash site observed one of the two bolts that secure the levers that move the tail rotor was missing, while the other bolt was loose because of a missing pin." If it was the walking beam bellcrank behind the hatrack, how could the FAA guy have seen that so readily? It will be curious to find out exactly which pieces came apart.

I can see how these things happen. I had *two* tail rotor failures during my time at PHI - driveshaft couplings came apart. Both were after maintenance had been performed and were in areas that were not preflightable (under the t/r driveshaft cover). The first happened right after the skids touched down on an offshore oil platform. Good timing, I'd say. The second one happened just after I'd lifted off to a hover in preparation for departing an oil platform. There was a bang and suddenly the world started spinning sideways. 30 seconds later and I would've been well into my takeoff. So, good timing again, I guess. Made me glad I wasn't one of those "yank and go" guys we often see.

[SASless]

Hands up....who routinely practiced Tail Rotor failures on six monthly Base Checks...where you actually manipulated the Throttle(s) and adjusted the collective setting to control yaw and did landings to the ground as part of the practice?

Or was that box checked following a verbal discussion with no actual hands on allowed or provided?

[Ascend Charlie]

Done a million of them over the years. When I transitioned to the S76B, I did the endorsement training and later went to Flight Safety in West Palm for the sim training.

When it came to tail problems, the instructor insisted that only an auto should be attempted, demo'd one, and I then did one. I then asked him to back it back up the glideslope while I showed him how we dealt with them. I flew the approach to a slow, gentle controlled run-on straight ahead. He was flabbergasted, said "do it again", so I did.

He grinned, and said "I'll lose my job if I teach that, so now we go back to the auto."

[[email protected]]

Lynx and Sea King sim every year (from TR failures in most stages of flight to TR control failures in every pedal position), AS 365 every sim trip plus practising TR control malfunctions regularly in the aircraft to fast running landings on the runway, 412 sim every sim ride.

The stuck pedal practice in the 365 backed up the teachings in the sim - it's all about training.

[wrench1]

If it was the walking beam bellcrank behind the hatrack, how could the FAA guy have seen that so readily?
Since the tailboom broke off be easy to see it. However, given no fatals the FAA guys probably did all the initial field work (open panels, interviews, etc) for the NTSB.

[SASless]

AC,

The FSI Instructor told you straight....the policy is to only teach FSI approved curriculum.

I know that from first hand involvement in such discussions where improvements were endorsed but not yet approved by the Standards Department.

That process at times could be like moving mountains but did ensure standardization on what was being taught by each Instructor.



Current 407 Pilots might compare this text to current RFM language for accuracy......

COMPLETE LOSS OF TAIL ROTOR THRUST

1. Uncontrollable Yawing to Right ( Left Side Slip)
2. Nose down tucking
3. Possible roll of fuselage
Hovering - Close Throttle and perform a hovering Auto landing. A slight rotation can be expected on touchdown.

In-Flight - Reduce Throttle to idle, immediately enter autorotation, and maintain a minimum AIRSPEED of 55 KIAS during descent.
FIXED TAIL ROTOR PITCH FAILURE - HOVER
Do not close throttle unless a severe right yaw occurs. If pedals lock in any position at a hover, landing from a hover can be accomplished with greater safety under power-controlled flight rather than by closing throttle and entering autorotation.
FIXED TAIL ROTOR PITCH FAILURE - IN-FLIGHT, LEFT PEDAL APPLIED
In a high power condition, helicopter yaw to left when power reduced. Power and AIRSPEED should be adjusted to a value where a comfortable yaw angle can be maintained. If AIRSPEED is increased, vertical fin will become more effective and and an increased left yaw attitude will develop. To accomplish landing, establish a power-on approach with sufficiently low AIRSPEED (zero if necessary) to attain a rate of descent with a comfortable sideslip angle. (A decrease in NP decreases tail rotor thrust .) As collective is increased just before touchdown left yaw will be reduced.
FIXED TAIL ROTOR PITCH FAILURE - IN-FLIGHT, RIGHT PEDAL APPLIED
In cruise flight or reduced power situation, helicopter will yaw to right when power is increased. A low power run-on type landing will be necessary by gradually reducing throttle to maintain heading while while adding collective to cushion landing. If right yaw becomes excessive, close throttle completely.

[60FltMech]

Forgive my ignorance on how the T/R controls work on the 407 and the nomenclature of the components in the system, I did a brief stint on the OH-58D back in 2008 which I think would have had a similar setup as the 407, but I don’t think I ever saw the installation of the controls that is being mentioned here.

Would the emergency procedures still apply if the tail rotor controls were completely disconnected/severed as in this case? Would the effect of this be the same as a “jammed” T/R control?

Or to ask in another way, would this still be a “fixed pitch” type situation, where I would assume the hydraulic servo would drive in one direction or another due to there not being equal pressure applied to the control rod that moves the servo pilot valve?

Thanks to anyone who can clarify, especially with pictures!

FltMech

[[email protected]]

discussions where improvements were endorsed but not yet approved by the Standards Department That's great when your Standards Dept are leading the way with the most up to date teaching and techniques - if not.............

[SASless]

That's great when your Standards Dept are leading the way with the most up to date teaching and techniques - if not.............

Yes....All professional training establishments......even the CFS is subject to that grain of wisdom theyt not?

Do RAF CFI's/QHI's teach whatever they fancy or are they expected to conform to approved standardized methods, procedures, and practices as a part of a formal curriculum and course of instruction?

Why would you think it odd for FSI or any other training system to use a similar method to formallze training standards and exercise a careful consideration when changing or altering those standards?

Aviation is an endeavor that involves change and progress as a constant......it takes time to effect useful and provident change.

[Two's in]

Any work or disturbance of a flying control system should be followed by an independent or dual signature maintenance check, i.e an independent set of eyes to confirm the controls still operate in the correct sense and have been secured/locked as appropriately. This seems to have fallen down the cracks here, through omission or error.

[wrench1]

but I don’t think I ever saw the installation of the controls that is being mentioned here.
The 58 controls are similar with several differences. Can't get a diagram to post but here's a basic explanation on the 407. Each pedal connects via a rod to a common pivoting bellcrank on the pedal mount. Then there are a series of single control tubes via 3 bellcranks and one walking beam (fwd) that route under the pedestal, up the broom-closet, through the roof box-beam until one tube connects to the TR servo linkage. The aft end of the servo is connected to another walking beam in the aft hatrack area which in turn is connected to the long TR control tube that terminates under the TR GB at a bellcrank. There is a short adjustable rod that connects this bellcrank to the TR blade pitch change mechanism mounted on the TR GB. Loss of hardware from this short rod could also cause a similar issue but it can be seen via a small access panel in the cowling normally checked during a preflight. As to the emergency procedures for loss of TR control I dont believe they address any physical break in the control system i.e, a missing bolt.

Any work or disturbance of a flying control system should be followed by an independent or dual signature maintenance check, i.e an independent set of eyes to confirm the controls still operate in the correct sense and have been secured/locked as appropriately. This seems to have fallen down the cracks here, through omission or error.
While a double check of critical system maintenance tasks is a good idea, it depends on a few other things whether that double check is required. And given the aircraft operated as a Public Aircraft will have to wait for the factual report/public docket to be released to see how their maintenance was performed and by who. And being a Public Aircraft does add another dimension to incident on several levels.

[lelebebbel]

Tail rotor failure and tail rotor control failure is known among the most difficult types of emergencies to be simulated accurately without a full motion rig. So, at least until it is known exactly what condition the tail rotor was in (full pitch, no pitch, negative pitch, anywhere in between, anywhere in between but moving, both blades the same or not....) I wouldn't be so quick to blame lack of training for anything. The difference between theory and practice is larger in practice than in theory.

[[email protected]]

Yes....All professional training establishments......even the CFS is subject to that grain of wisdom theyt not?

Do RAF CFI's/QHI's teach whatever they fancy or are they expected to conform to approved standardized methods, procedures, and practices as a part of a formal curriculum and course of instruction?

Why would you think it odd for FSI or any other training system to use a similar method to formallze training standards and exercise a careful consideration when changing or altering those standards?

Aviation is an endeavor that involves change and progress as a constant......it takes time to effect useful and provident change. Standardisation is good - staying in the dark ages isn't.

The instructor's response to ACs demo speaks volumes about an organisation.

If he had said 'let me get the CFI so you can show him that' - that would be a progressive training organisation.

[Bell_ringer]

Are we not assuming the tail rotor was stuck in a fixed position?
With a loss of linkage, would it not be possible for the blades to travel and pitch to be variable?
If such a scenario is possible that could make it a bit more unpredictable and challenging to deal with.

[meleagertoo]

Two questions occur to me.
Isn't it a good idea to use the runway for a running landing if yaw is likely as skids skid better and trip less on tarmac than on grass? (Assuming he had enough control to hit a runway).

What level of training and licence does a US Police Lieutenant have? Is he likely to have had the levels of tail rotor failure training that have been described above?

[[email protected]]

BR - yes a non-fixed TR pitch would make things considerably more difficult and the Leicester 169 crash showed what full travel to negative pitch can do - it looked very controllable on the first part of his approach - at least he is still around to give more details of what he had to deal with.

Mel2 - he may have had no access to a simulator for detailed TR malfunction training so I guess it would be limited to his Type Rating training and subsequent LPCs - plus whatever experience he had before on other types.

[Bell_ringer]

BR it looked very controllable on the first part of his approach - at least he is still around to give more details of what he had to deal with.


My initial thoughts looked like he was on track for a successful run-on, perhaps a bit too steep, but he bled off too much speed and it caught him out.
Initially, it appeared there was enough control for a second attempt, or perhaps, just using the remaining runway to get it pointing in the right direction.
It skids quite nicely at a rakish angle, so the outcome is a little surprising.
If memory serves, Bell now has pretty decent sim facilities for the type, whether US services are put through that degree of training I would not know.

[Lonewolf_50]

If memory serves, Bell now has pretty decent sim facilities for the type, whether US services are put through that degree of training I would not know.
The depth, quality and frequency of training can be budget constrained for a variety of reasons. (Or excuses).
The question you raise is a good one that one hopes is addressed in the final report.

[60FltMech]

I confess I hadn’t watched the video till now, didn’t realize it was there🤣 As others noted he looked pretty good on approach, I wonder if the ground rush freaked him out, it’s almost like he was descending then was like “oh crap!” and ballooned up. It was like he was set up for a great run-on landing, like he had a good grasp of the process but not enough “reps” actually flying the profile?

When our guys go through their annual stands ride that’s unfortunately the only time they are able to do autorotations low level, terminating at a hover or rolling on (touchdown autos are not allowed) The ground rush is unnerving to me as a back seater for sure, tho most guys take the opportunity to do a few while the boss is in the other seat.

i wish we could do them as a crew more often but the regs say have to have stands pilot up front. And SOP says instrument rating required for the job but no instrument flying allowed. As others have already mentioned, risk aversion strikes organizations pretty often, right or wrong.

FltMech

[[email protected]]

60 Flt Mech - yes the ground rush is a problem - helicopter pilots are conditioned to reduce speed as they get close to the ground because they normally come to the hover. On a fast approach many pilots sub-consciously reduce speed to make the picture appear 'normal'.

[SLFMS]

Are we not assuming the tail rotor was stuck in a fixed position?
With a loss of linkage, would it not be possible for the blades to travel and pitch to be variable?
If such a scenario is possible that could make it a bit more unpredictable and challenging to deal with.

I wondered the same thing there was a little bit of left yaw that was quite quick just before the right. Possible it was from lowering the collective or from wandering pitch.

Pedal jams do not require committing to a bad approach or excessive urgency. Up to about 90deg off centre it’s possible to go around although at that angle you have to be aggressive. He looked perfect on approach just too high. Perhaps a second run lower would have gone better but who knows without been there.

Good tip is change speed or collective individually but never together. Small inputs too, unless aggressively accelerating with cyclic because you’ve got to slow

[JimEli]

Based upon my experience developing and qualifying helicopter simulators with the FAA (from a test-pilot perspective) the flight model of a simulator is based upon actual flight test data. The data incorporates most phases of helicopter flight (hover, climb, descent, cruise and autorotation). Obviously, loss of tail rotor is not measured. Then engineers take the recorded flight data and turn it into a flight model. The flight model is the simulation. Test pilots then tweak it and confirm it to fit what they know as "real."

Since the dynamics of a loss of tail rotor can vary (immediate or slow onset, partial to total loss, component shedding, incidental damage, etc.), the resulting enactment you experience in a simulator is closer to fantasy rather than reality.

During development, the engineers apply the physics to the method selected for the loss of tail rotor scenario. Then the test pilots fly it and tweak it. Here's the important part to understand: the failure MUST be survivable otherwise there is no constructive point to the simulation; FSI doesn't exist to produce frustrated and hopeless pilots.

It has been my experience that most tail rotor failures when based upon just the engineering physics quickly lead to loss of control and catastrophic results. And the interplay of everything (environment, onset conditions, aerodynamics, dynamics and physics) makes it just a guess based upon some theory and a little experience. And we always needed to "calm" or "dampen" the theoretical guesses down to allow survival of the situation for most pilots.

Consider all of this the next time you step from the simulator slapping your back.

[RVDT]

+1 - What he said.

[helichris]

+1 - What he said.
Agreed.

[Bell_ringer]

It is obvious that trying to simulate a complete loss of a tail rotor would have limited value.
This accident has nothing to do with tail rotor loss, it was operational, from a drive perspective, control was impaired.
That is something that can be worked in a simulator, after all we can do that that in an actual aircraft to varying degrees, so I wouldn't write off time spent working on that scenario.

[[email protected]]

Agreed - TR drive/total failures are difficult to model but TR control failures (ie stuck pedals) are easier to model and also practice in the aircraft - as I mentioned earlier, doing stuck TR exercises in the aircraft to fast running landings on the AS365 proved the simulator teaching was valid.

[ShyTorque]

In the mid 1980s I was one of two RAF QHI pilots who were tasked by MOD to use a Puma simulator to come up with better guidance wrt tail rotor malfunctions. At that time there was very little in either the pilot manual or the flight reference cards of any use. Some of the “old school” RAF QHIs were of the blinkered opinion that if a tail rotor failure of any sort occurred (note the different wording to that I used) it could be resolved by shutting down both engines and autorotating. That’s all very well until a tail rotor control failure occurs where the TR is still producing thrust but that thrust isn’t controllable by the yaw pedals, especially one that sticks at positive pitch. In that instance, shutting down the engines might be the last thing a pilot ever did.

We came to realise that some control failures, ie those where the blade pitch runs away to either maximum positive, or maximum negative pitch, are likely to be non recoverable. The latter occurred in the Leicester football club disaster, where high main rotor torque was being used and TR blade pitch ran away to maximum negative, or close to it. There’s no getting away from that.

However, most modern helicopters have a safety device of some sort or other such that following a disconnect of the pilot controls the TR pitch is placed in a near neutral position. This should allow, in some cases, for the pilot to fly the aircraft for some sort of controlled landing; probably a running one.

Following our simulator work, we used to teach our RAF Puma students to try to achieve a configuration whereby the aircraft nose was held off to the side on the approach to a constant speed running landing and then to apply just sufficient (but very careful) collective pitch to bring the nose back into line for touchdown. This may result in running on at some speed. On the Puma the MR blades pass the nose from left to right so the nose had to be held off to the right. Raising the collective applies more MR torque and this brings the nose round to the left.

An aircraft with blades that rotate the opposite way, ie passing the nose from right to left, needs the nose held off to the left.

Without regular training on type this can be difficult to visualise in the air, especially once adrenaline kicks in. However, I used to tell my students that the safe side for the nose on the approach is the retreating blade side. This obviously works irrespective of aircraft type and hopefully pilots will remember that from the aircraft start up they just did! If that configuration can be achieved, there is a reasonable chance that a successful landing can be made.

If on the approach the nose swings from the “safe” side through the twelve o clock to the other side, it’s unsafe and things will get worse at touchdown so either more airspeed or less collective pitch is needed. Obviously, finding this out close to the ground is a very bd situation so if possible the pilot should carry out a dummy approach at some altitude before committing to a landing.

Fly safe out there! ;)

[[email protected]]

Shy - that is exactly what we taught on the 365 and it worked.

We also taught how to assess your minimum approach speed by carrying out a level, very gentle decel (at a safe height so you could dive on speed if required) to identify when the nose started to break away.

Once the basic technique is understood then it can be finessed - but if you have never had any training you will be lucky to survive it.

Good to see the RAF being so proactive 40 years ago

[JimEli]

It is obvious that trying to simulate a complete loss of a tail rotor would have limited value.
This accident has nothing to do with tail rotor loss, it was operational, from a drive perspective, control was impaired.
That is something that can be worked in a simulator, after all we can do that that in an actual aircraft to varying degrees, so I wouldn't write off time spent working on that scenario.
FWIW, fixed-pitch tail rotor situations are not necessarily easier to model. It is hard to determine fuselage and appendage aerodynamics, especially at varying airspeeds with increased yaw and roll angles. Data recording flights are generally limited to just the basics. And the interplay of factors (stability augmentation systems anyone?) makes any abnormal/un-measured situation a guess. Again, my experience showed that when pure engineering physics were applied, the situations didn't always work the way the manual read. Most fixed-pitch scenarios I worked on included varying degrees of tweaking in order to produce acceptable results.

All of this is exacerbated by something you may not be considering. The process of fine-tuning the flight model further distorts reality. Slightly tweaking one thing here, can have huge undesirable effects on something else. It could even result in unknown effects: things I lose sleep over.

For example, one aircraft I worked on didn't seem to have the yaw stability exhibited by the actual aircraft (or any aircraft for that matter). It would swap ends in cruise flight with insignificant amounts of pedal application. It was obvious some component(s) of the model were wrong. But how is the fix accomplished? Do you reduce the power of the tail rotor, fudge with the vertical fin contribution or fuselage influence, amplify the airspeed impact, or just increase the overall yaw stability factor? Et cetera. One avenue we toyed with resulted in a helicopter that no matter the amount of pedal applied it was incapable of turning in a hover. All of this contributes to the realism of the whole simulation.

Helicopter simulators might be closer to a unicorn than the real animal.

[[email protected]]

Yet the 365 handled exactly like the sim with regard to TR control failures so Airbus/Aerospatiale must have got something right.

Disregarding training in the basic techniques because the sim isn't exactly like the aircraft is more dangerous than believing everything the sim can do will be exactly representative of the real aircraft.

If on the day - heaven forbid it happens - you have a real failure and the aircraft doesn't behave exactly like the sim, then chances are you will at least have a reasonable idea of how to deal with it rather than none at all if your training organisation has completely disregarded such scenarios.

[JimEli]

Yet the 365 handled exactly like the sim with regard to TR control failures so Airbus/Aerospatiale must have got something right.
...
Manufacturers have access to data that mere mortals only dream about.

[RVDT]

And "mere mortals" is a wide variable.

[[email protected]]

It wasn't the Airbus sim at Mariagne but the Heli-Union sim at Angouleme - probably the same data set though.

[ShyTorque]

Yet the 365 handled exactly like the sim with regard to TR control failures so Airbus/Aerospatiale must have got something right.

Disregarding training in the basic techniques because the sim isn't exactly like the aircraft is more dangerous than believing everything the sim can do will be exactly representative of the real aircraft.

If on the day - heaven forbid it happens - you have a real failure and the aircraft doesn't behave exactly like the sim, then chances are you will at least have a reasonable idea of how to deal with it rather than none at all if your training organisation has completely disregarded such scenarios.

Agreed. One RAF Puma pilot suffered a TR pitch spider failure over the sea, with positive pitch applied. The aircraft was flown to a good water landing and there were no injuries. Despite not having floatation gear it was later recovered more or less intact. I didn’t get to speak to said pilot directly but I was told he said that he was very glad that he had done the sim syllabus because without the TR malfunction training we devised he reckoned the outcome would probably have been very different.

[SLFMS]

I understand the point made in reference to Sim shortcomings. It’s obvious when you’re in the Sim when some modelling doesn’t feel right. Often I find comparison to rotor droop on auto entry vs recovery doesn’t feel right.

Surely jammed pedal from control been locked is not too hard to emulate. After all in singles it is simulated by the IP fixing their feet on the pedals and not moving them. Incidentally that is quite hard to not instinctively do while close to the ground and not straight.
It is not to hard to verify if it’s like the actual aircraft. I’ve done simulated jams in the actual 76 and the sim felt exactly the same to me.
Happy to be educated if I’m wrong?

I understand completely T/R failure is a different ball game and is theoretical with test pilot input.

[ShyTorque]

SLFMS,

Of course to some extent it can certainly be practiced in the real aircraft but I expect that you’ve not tried doing it with anywhere near full pedal offset (for example, the Puma tail rotor range in pitch is plus 35 degrees to minus 17).

But it’s good that you know the principles of how to deal with it.

The RAF began using a Puma simulator (which was actually a AS332 Super Puma model owned by Helikopter Services at Stavanger, rather than a more representative HC1) following a fatal accident during a civilian engine failure practice. Until then we used to load the aircraft to MAUW using a floor frame and lead weights and pull throttles all the way back, both in forward flight and in the high hover (the sortie was known as “Swoops and droops”). There were quite a few close calls and the civilian accident was the final straw. An ex Puma squadron boss, who had always been against the way the RAF carried out these practices, got himself promoted and into the office which made these decisions. I think he was right. I once experienced quite a close call myself when a squadron instructor ran the undercarriage through a crop of cabbage after a flare recovery during his demo and flared too low. A MAUW running landing at 40 kts into a soft field would have been interesting….we only just got away with it.

Tail rotor malfunctions training was added to the syllabus quite early because RAF students went to the simulator before flying the actual aircraft. It was used as a procedure and emergencies trainer and was far from representative of RAF aircraft because the cockpit was totally different and the actual aircraft are physically different.

[SLFMS]

Shy Torque that sounds like a good decision to me re the fully loaded flights. I imagine brown pant moments were fairly common.

You’re right about the pedals not been at full deflection. I’ve always thought that’s a different scenario and recovery is go to be difficult or near impossible. The 169 at the football field didn’t have much of a chance. Assuming pedal doesn’t hard over for failure I’ve always considered moderate jams more realistic as full deflection is uncommon for the vast majority of flights. Some types for control linkage failure will go to neutral position.

One thing I have always wanted to experiment with is cross wind with jams in heavier aircraft. In light pistons and light turbines the wind on the left(anticlockwise) makes a huge difference to the run on speed for a right jam. I’ve always wondered how effective it is in larger aircraft.
that’s something I don’t think the Sim models well it just seems to factor airspeed over the nose.

[ShyTorque]

Yes, but “Lucky left / Rotten right” as some say, only works for anti clockwise rotors. Which is why I always referred to the retreating blade side as being the safe side for offsetting the nose in the unlucky event of…

Throughout my RW career (now done, apart from the odd trip) I regularly changed to and from aircraft with MR blades that rotated in opposite directions (Sikorsky Aerosptiale/Westlands - Sikorsky - Aerospatiale- Sikorsky - so I always knew it was important for me to remember what was what!

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SLFMS - with larger aircraft there is often more fuselage area for a crosswind to affect and in some RFMs the drills encourage a crosswind approach with the wind from the retreating side to aid directional control.

[SLFMS]

Shy lucky left rotten right is what I’ve always used too but not something that works well for French Helicopters….

Crab while the surface area is much larger so is the torque reaction on larger helicopters. I’d like to play with it a bit as I did in singles but can’t see that happening any time soon. I suspect it is type variable.

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Fair point - you are also dealing with twins that often don't have throttles on the collective so some of the finessing you might do in a single is difficult to do.

I have tried doing it single engine in a twin with the remaining engine in manual control for fast running landings but not really a realistic option single pilot.

With stuck pedals in higher pitch settings we used to look at decreasing NR to reduce the TR thrust as well - didn't try that in the aircraft though.

[Ascend Charlie]

It took some gentle manipulation of one of the roof-mounted throttles on the S76 to keep it straight on the (simulated) runway. Not too difficult at all. But it was a simulation, in the real event the pilot might be reluctant to take his hand off the collective.