As350 Hydraulic System Failures: too many??

[rotorpol]

Just read the new of hawaii as350 crash, high experience pilot, with Hydraulic Failure, apparently not being such a difficult procedure, results extrange to me, the sad final result.

Last week I was informed of the way an accident happened in France at SAF helicopters some time ago, with a helicopter property of Heliand.
High time instructor and a pilot training "Gov failure procedures" in a AS350B3.

At some point in flight, having normal rotorRPM variation due to flying in manual mode, helicopter started shaking violently and the controls were extremely difficult to move.(Just like with Hyd Failure but worse due to vibration).
Final result: crashed in a field, both survived.(helicopter completely destroyed)
Eurocopter explanation:Hydraulic system servos entered in resonance due to Hyd Fluid pressure variations caused by Rotor Rpm variations.
There is already an SB to solve it, that as far as i know is not aplied to new AS 350´s.



HOW MANY OF YOU KNOW OF SIMILAR HYDRAULIC SYSTEM FAILURES IN AS350B3??
AND WHAT EXPLANATION OF THE CAUSE WERE YOU GIVEN??:confused:

[gulliBell]

I think there was an accident in Los Angeles (early last year?) involving a media AS350. Aircraft experienced a hydraulic malfunction and female pilot crashed (fatal) whilst attempting to land.

I am also aware of instances of Training Captains scrubbing female students qualifying on type, due to not enough physical strength to fly the helicopter without hydraulic boost.

Fortunately us 76 & 412 pilots don't get scrubbed for the same reason!

[DeltaFree]

I do not know about the B3, I know B1s and B2s are stiffer to fly hyd out than the Bs but I am surprised to hear of crashes, and people being chopped due to lack of physical strength. Is it insufficient training? Or is it really a problem EC should be looking at?
It is not easy, but slow steady control movements work for me. Suddenly hoofing loads of power after a quick approach does cause all kinds of wobbles, but as with most helo flying smooth flying and pre-empting what will happen makes life much easier. OK engine out hyd out would be v interesting but then it really would not be your day.

[TheShadow]

that are too close together - and suck away the hyd press. (should be toggle switches for the test function - there's an STC out for the swap-around of the push-buttons)

http://www.airsafety.com/reports/ROWS070308B.pdf

[SASless]

I have flown several types of helicopters that produced hard to move controls when the hydraulics quit (and some that were impossible to move) but none should have caused a crash during landing.

If one were to add an engine(s) failure forcing an autorotation....I would imagine the result would be a bit interesting.

Why is it the 350 has such a miserable record for inability of controlled flight after a loss of hydraulics? Thus far it is also the only aircraft I have heard of that has "jack stall" issues as well.

Is there something lacking in the design of the flight control system?

Rumors have been heard the particular aircraft has had a history of problems.

[stas-fan]

I'm sure this has been thrashed to bits before as a subject, but for a very good reason Auz military do not allow, and Brit mil recommend you don't, fly below 10 knots hyds out. Several lost helicopters have proven this around the world. Last time I was in McAlpines in Oxford there was a victim being repaired. :O

In the Gazelle days we had to take 2 pilots up below minus 10(?) degrees C due to Hyds out properties. Lower temp was possible by proof of performance at lower increments with 2 bods on the sticks.

Same reason Brit Mil do not fly thier BBs IFR single Pilot, it can take too long to get it down single pilot Hyds out before fatigue gets you.

(Expect a heap of tosh about friction nuts and more beans for breakfast but I'll ignore them in advance!)

[Fun Police]

i'm going on 2K hrs on type so i have done a number of hydraulic failures in training. i have never had a real one, but in my experience, the astar without hydraulics is entirely manageable. it is a lot of work and may involve getting the appropriate knee involved in order to some of the load of the shoulder, arm, wrist, and hand.
whether or not the hydraulic system is adequate for the job has been debated many times before, but if you are not doing something that you should not be doing, then servo-transparency or jack stall is very unlikely. most of the time i have in this type is doing production longline work all over North America, and in the course of normal duties i have never experienced it.
the design of the system may leave something to be desired. keep in mind i am not an engineer, but there is something about running a constant pressure pump in a closed system that seems questionable. also, the belt drive might be considered "fromage" but again, it has served me well enough.
fly safe.

[SASless]

A trick that works a treat on the Bell 204/205 single hydraulic versions and Bell 206 as well as the Sikorsky S-58T with the Aux hydaulics out.....was to apply a very gentle pressure in the direction you wanted the cyclic to move and wait while the feedback forces motored the stick to the desired position and then relax until you needed to move it again.

The collective on most Hueys was easy up and hard down which could be a reason to eat Gorilla Grits in the morning but still not a big deal.

I always felt I was carrying the helicopter with my left hand when doing without the Aux Hydraulics on the 58T.....perish the thought of a two hour flight like that.

Having never flown the 350.....does any of that sound like what a 350 flys like without hydraulics?

[nigelh]

I think you will find there is no "motor" on the cyclic on the 350. When you do hyd out training there is a very simple set of rules as to the order in which you disable the system....this is in order to use the reservoir available which will give you around 6 -10 control inputs before it runs out and then when you have slowed the aircraft to say 80 kn you turn off the hyd all together . This is to avoid having partial hyd support to one or other servo. When you turn the main hyd back on you first need to have replenished the reservoir by re pressing the hyd test button. I think sasless has his own issues with 350 ,s and find his " is there a problem with the system ?" somewhat insincere !! Certainly girls have crashed these machines in the past due to very heavy controls without hyd and even for a man they are heavy especially in the hovver. ( i know ...not recommended )

[Fun Police]

the flight manual states very clearly that "hovering should not be attempted" because it is a bear to handle in the hover. I know of a machine that was written off in canada because the driver tried to put down a load and then, lay down the longline and he lost control in the hover.
a low speed run on is recommended, which is tough enough, especially with a B3 tail rotor. it is definitely doable though.
i can see how some of the fairer sex would have trouble with a hyd failure as the machine does become very heavy

[SASless]

I think sasless has his own issues with 350 ,s and find his " is there a problem with the system ?" somewhat insincere !!


Having clearly stated I have not flown a 350.....I posed a question where I asked if the 350 flight controls "felt" like some aircraft I have flown before without hydraulics.

Perhaps you read more into the question than was asked.

[Hidden Agenda]

I find it interesting that in most organisations we concentrate on two aspects of a hydraulic failure, immediate actions and the landing.

Certainly the control forces on the AS350B3 are heavy and they are no better, and probably worse, on the EC120. I wonder how many of us would handle a hydraulic emergency say some 60 + miles out to sea with no option but a return to land. I fear that many of us would be absolutely knackered by the time we were ‘feet dry’ that the landing might be rather exciting and that some of us might not even make it; either running out of fuel because they flew so slowly (with less force required on the controls) or just running out of stamina trying to keep the aircraft in a higher speed range.

Does anyone have any experience of a practice, or a real, hydraulic failure in one of these types that lasted for more than just a few minutes? How did you do?

[wiisp]

Hello,

We work and train in EC 120 and AS 350. The machines behave quite alike, but 350 need almost 2 times more power to control at low speed.. They are both controllable in flight, landing , hover and take off. A very few tricks but lot of pwer and guts is required.. Most important is the 350 goes right down to 15 knots, then it goes to left with EVERYTHING, be prepared with the controls. If you loose the machine to left it is very tough and you need LOT of control movement to get it back.
SASless, the problem is the elastomeric stuff, straight and level works with small movements w/o any bigger effort but at low speeds it feels like whole world is against you. And wrong rubber parts below -25 C makes it impossible.

fly safe

[Arm out the window]

SASless, I've done a lot of practice hydraulics off in the Huey and AS350B and BA, and never noticed one being particularly harder than the other control-forces wise, with run-on landings or in the hover (not common practice, but done a few times).
Never had a real hydraulics failure in the AS350 so can't comment on any differences from the practice case - as nigelh mentioned above, there are accumulators on the cyclic / collective servos that give you a little bit of time to get the speed down, then you isolate the hydraulics and run it on.
Similar magnitude of push and pull forces to the Huey, I reckon, although maybe pedals a bit harder in the Squirrel.

[RVDT]

In response to SASless question and NOT pertaining to what may or may not have happened in this accident:-

The gross weight limitation of the 350 is the controllability without hydraulics at the first instance.

Of the models in current production the B3 has the WORST useful load internally due to this restriction. The B2 is lighter and the B4 has Dual Hydraulics and subsequently a higher MTOW (2427 kg). Frankly unless you are conducting sling or high altitude work I have never understood why you would want a B3. There is no significant internal performance over a B2, unless of course you are operating as mentioned before, and you have a slightly lower specific range ~ 2.5 - 3%.

Problems you can have................

Hydraulic failure and assymetric or no pressure in the accumulators meaning one servo will run out of pressure before the others. The hydraulics should be turned "OFF" prior to the deletion of the accumulators to be sure.

Misuse/Misunderstanding of the "HYD TEST" and "HYD OFF" switches.

"HYD TEST" simulates a failure of the hydraulic pump and is a method of testing for the assymetric problem. Move the cyclic until the accumulators deplete and make sure the assistance stops symmetrically.

"HYD OFF" is exactly that. Turn the hydraulics "OFF" and thats what you get no assistance from the accumulators, but you WILL still have assistance in the yaw channel via the compensator.

Now heres the catch - when there is no hydraulic pressure and you push the "HYD TEST" button you will purge the accumulator in the yaw channel compensator which is standard procedure after shutdown. In flight with a hydraulic failure if you activate the switch this accumulator will no longer assist you and you are out of the bounds of the certifcation limits. The pedal pressure required will lift you out of the seat and the yaw will more than likely be uncontrollable to the left on reduction in airspeed. Couple this with a heavy cyclic and it's interesting. Its worse in the B3 than the B2, have a look at the difference in the tabs added on to the TR blades which you are in competition with.


Exceeding gross weight:- In a B3, unless you keep an eye on what you are loading into the helicopter, it is easy to exceed the maximum internal gross weight without seeing any obvious indications of exceeding these limits. This helicopter can exceed its internal gross weight limit by 550 kgs (1212 lbs) using TOP at SL ~ 25 deg C - i.e 25% over internal MTOW!!!!

This accident report will probably enlighten you as to how it all works. Unfortunately there have been numerous cases of misunderstanding of the system.

http://www.tsb.gc.ca/en/reports/air/2003/A03O0012/A03O0012.asp

[oldbeefer]

We operate a fleet of 30+ BBs, each of which has over 5000hrs. Since day one, we have had NO HYD FAILS, so the system is reliable if serviced correctly. A hyd fail in flight gives the pilot at least 20secs of manoevring before the accus exhaust - more than enough time to reduce speed to 65kts. At this speed, there are virtualy no loads on the controls - it's only when speed is reduced on short finals that the loads increase. As long as a run-on lamding is made with 10kts across the disc even small, feeble students are able to put down with no problems. But, ignore the instruction in the RFM and try to reduce speed to a hover, and life gets more difficult (but not impossible).:=

[Shawn Coyle]

If I'm not mistaken, the Australian military did a lot of testing of these machines hydraulics off, and didn't much like the results...
I don't believe the report was ever made public.

[Finnrotor.com]

wiisp
Join Date: Nov 2005
Location: Finland
Posts:7
We work and train in EC 120 and AS 350.

Not here to steal the thread but i'm just wondering what company in Finland operates both 120 and 350? I quess there isn't any..:hmm:

[Arm out the window]

Australian military-wise, we operated the B, which was then modded to BA, without the compensator in the tail rotor hyd system.
Many, many practice hydraulics off approaches were flown without much in the way of dramas using the flight manual procedure of detecting the problem, slowing to an appropriate speed if required and then operating the hydraulic isolate switch to dump all pressure from the accumulators at once and proceeding to a running landing.

There was an accident where a student wasn't sufficiently strong to control the helicopter during a running landing and the instructor couldn't recover - they rolled it on its side on the grass. I don't know the full details of that one but I vaguely remember hearing it might have been that the hydraulic test switch was used to simulate the failure, but they didn't subsequently use the hydraulics isolate, which may have contributed to the problem.

Some time after I left, I believe they fitted the tail rotor compensator, probably after the investigation Shawn referred to? Perhaps someone in the know can elaborate on that.

Anyhow, my point is that in my experience, flying those variants of Squirrel / Astar with hydraulics off a lot (including hovering although that wasn't done as a rule), there wasn't a problem for the average pilot if flight manual procedures were followed. Maybe the other models are significantly harder, I don't know, but at least in the B and BA there was no big scary issue.

[Aynayda Pizaqvick]

Does anyone have any experience of a practice, or a real, hydraulic failure in one of these types that lasted for more than just a few minutes? How did you do?
I have done about 15 mins Hyds out (simulated) ending in a run on landing. Yeah, it can be hard work but if you make the most of the accumulators to get the aircraft in a level attitude (ideally for 60 knots if my memory serves me correct) then you can just let the collective come up and then control the cyclic with two hands until you need to begin the approach. I have done dozens of Hyds out landings in the Squirrel and as long as you keep the touch down airspeed above 10 knots and avoid a cross wind from the right then they do not present a problem!

[wiisp]

Finnrotor.com,

Currently working in Sweden and Greenland.. Just livin' in Finland..

fly safe

[Aser]

Recollection of PREVIOUS accidents:
Causes of previous helicopter crashes include worn, rusty hydraulic pump, pilot error
• Probe's focus: hydraulics
By Jan TenBruggencate
Advertiser Staff Writer
Previous cases of hydraulic failure on helicopters include:
# An AS350BA helicopter operated by Heli USA that crashed near the Peach Springs, Ariz., airport after a hydraulic failure on Sept. 11, 2002. In this incident, the pilot reported the controls were not responding. Witnesses said the helicopter began spinning when it was 30 to 50 feet from the ground. In the hard landing, the main rotors cut off the helicopter's tail boom. One of six passengers received minor injuries, but the pilot and the other five were not hurt.
The National Transportation Safety Board investigation found that the helicopter's hydraulic pump had failed due to lack of lubricant, and that even though it had been serviced only 15 days earlier, the pump was severely worn and rusty.
"A metallurgical examination of the hydraulic pump revealed that it had failed due to the wearing away of the splines on the coupling sleeves. ... There was rust on the front retaining rings and bearings, which indicated that there was insufficient grease in the splines to retain it or lubricate the splines," the NTSB report said. It cited as causes of the crash the pilot's failure to follow correct procedures for a landing with hydraulic failure, Heli USA's faulty maintenance, as well as a manufacturing flaw in making part of the hydraulic pump.
# An AS350B3 operated by Native American Air Ambulance crashed near Scottsdale, Ariz., on Nov. 2, 2003, after the pilot inadvertently hit a hydraulic switch and was unable to prevent a resulting spin. Injuries were minor.
# A Texair Helicopters crash on May 24, 2000, in Patterson, La., with an AS350B2 in which hydraulic failure was listed as the cause. The pilot and single passenger suffered minor injuries when the helicopter flipped on its side on landing. Investigators found that the pilot had inadvertently turned off his hydraulics after a tail rotor failure.
# A Helinet Corp. AS350B crashed March 26, 2000, in Van Nuys, Calif., after a loss of hydraulics due to a mechanical failure. The helicopter rolled on its side, seriously injuring both the pilot and her passenger, a television news cameraman.
The NTSB said that the pilot, who was 5 feet 1 and weighed 108 pounds, should have landed as soon as possible, instead of flying back to her home airfield. She simply wasn't strong enough to control the helicopter for as long as she needed to for the flight, the NTSB said.
"The National Transportation Safety Board determines the probable causes of this accident as follows. The pilot's failure to land as soon as practical. ... Contributing to the accident was the pilot's physical stature and strength," the agency's report said, in part.
Reach Jan TenBruggencate at [email protected].
source: http://www.honoluluadvertiser.com/apps/pbcs.dll/article?AID=/20070310/NEWS/703100330/1001
Regards
Aser

[RVDT]

Synopsis
The helicopter was positioning for forestry spraying operations and was being flown by a student pilot who was receiving type-rating instruction. The instructor simulated a hydraulic system failure by pressing the HYD TEST (hydraulic test) button. Whenthe student pilot began to experience control difficulties, the instructor took over and asked the student to turn the hydraulics back on. The student mistakenly selected the auxiliary hydraulics button, by which time the helicopter was uncontrollable in yaw. The instructor managed to reset the HYD TEST button, but hydraulic power was not restored. He was unable to prevent the rotation continuing so elected to place the machine on the ground before the situation worsened. The helicopter rolled onto its side upon touching down. Hydraulic failure is normally simulated in the AS350 series by depressing the HYD TEST button. This depressurises the system, and the three accumulators in the roll and pitch circuits will continue to provide hydraulic assistance long enough for the pilot to reduce speed to the safe operating range of between 40 and 60 knots. Once the accumulator pressure has been exhausted, the aircraft is effectively under manual control, and the pilot will feel significant loads on the controls. The flight manual actions for hydraulic failure are firstly to reduce collective pitch and adjust the airspeed to between 40 and 60 knots, and secondly to operate the Hydraulic Cut-Off switch on the collective lever. This switch serves to eliminate any residual pressure on the servo pistons, minimising the mechanical loads required to move the control linkages. It also cancels the warning horn, which sounds when hydraulic pressure is lost. The B2 model has an additional accumulator in the yaw control circuit. Operating the HYD TEST button depressurises this accumulator immediately, but in the case of an actual hydraulic failure, this accumulator remains pressurised indefinitely (according to the flight manual), even when the collective switch is operated. Simulating hydraulic failure in the B2 model by using the HYD TEST button will result in control loads being felt immediately in the yaw circuit, with the normal delay in the roll and pitch circuits. There is a note in the emergency section of the flight manual that states: "Do not press the HYD TEST button; this will cause immediate depressurisation of the accumulator and the resulting control loads may be heavy." In this occurrence, when the instructor simulated hydraulic failure by means of the HYD TEST button, the student would have immediately felt control loads though the yaw pedals but normal forces on the cyclic and collective until the accumulator pressures discharged. By the time the latter occurred, he should have had the speed within the recommended range and operated the Hydraulic Cut-Off switch on the collective lever. However, the collective switch was not operated in this case, and the instructor did not reset the HYD TEST button until after control difficulty was experienced. This action did not immediately restore the hydraulic system to its normal operation. The instructor was of the opinion that this was due to the time the accumulators took to recharge.


10,000 hour pilot with approx 4000 on type.


Looked at the BEA site in France and back as far as 1997 there has never been an accident recorded with the 350 involving the hydraulics.

A thing to remember with all of this is if you have a hydraulic pump failure (in a machine with the yaw compensator) and engage the "HYD TEST" button, you have cooked your goose with the yaw compensator. You cannot get the assistance of the compensator back as you have depressurised it and as you have no pump there is no way of re-pressurising it!! The yaw channel forces on reduction of speed will be larger than you really need or may be able to contend with.

[3top]

Hi all,

just received a factory transition for the B3.
The instructor would not use the HYD button on the console to simulate a failure, but hit the warning light button (incl. the gong) and call out the emergency.
If it was to be a HYDR failure, I would slow down to 65kts and switch off HYD at the collective and then slow further to about 55 to 60.
Reinforced with a video clip from some botched test flight in Mexico, I was indoctrinated to NEVER touch the HYD button of the console in flight when a real HYD failure is suspected, as it would render the TR basically unusable.
The only time ever one should touch the HYD-console button (in flight) is when a loss of TR-control is suspected (pedals stuck, etc.) In this case pressing the console-HYD-button will return the pedal/TR position to somewhere neutral.
After that - 4-6 sec, one would reset the HYD button in the up/on position to restore hydraulics to the rest of the system.
The resulting approach was done at about 75 kts with left slip, slowing down for a running landing at about 35-25 kts, but with hydraulic control on cyclic and collective.

It was mentioned that a few accidents (like the one news-copter in New York) where due to inadequate pilot training:
Something goes wrong with the hydraulics and for lack of knowledge they just hit "some" hydraulic button, with resultant loss of TR-control.

If in a B3 and suspecting anything wrong with hydraulics, the collective is the only place to switch them!!

3top

[Dynamic Component]

If you don't like the single hydraulics on the B3, get the dual hydraulics. (Should be standard equipment if you ask me:})
Or go fly a 407 ,which they say chops its own tail off, or a 206L which won't carry the same payload, or a Koala.........(ahhh shucks- I can't find anything wrong there except for the uncomfortable seats):hmm::E:ok:

[Devil 49]

3top, have they relabelled the hydraulic's "TEST" buttom as "HYD"?
What you're expounding on sounds like the "TEST" circuit to me...

[3top]

The button is called HYD TEST. In the FLight Manual we got for the course it is still called ACCU TEST.
You are right, it is the accumulator test circuit.
According to the instructor, some accidents happened, because less than well trained pilots "paniced" and pressed "whatever" HYD button when the hydraulics failed.
By switching the collective HYD switch off you get non-hydraulic control back, but not on the TR, as the compensator is depleted too - that would only apply if you have a TR-control loss and want the pedals/TR somewhere centered, you still don't get control back, but you have a chance to run it on.
Without hydraulics this is going to be a hard game. (...as was wit the NY newscopter - this one went around a few times, before "coming to a stop"...)
You are also adviced to land as soon as possible if you have a HYD failure, because you will fatigue in short order.
My instructor said 2 min without HYD every day will take care of any workout needs you have!! :))

3top

PS: Watch the B3, this beast will destroy any piloting skills you might have had - there is just NEVER any lack of power - just pull collective. If you get just somewhere near the yellow arc you know you are severly overloaded :))

Also the Koala is no good for tall pax, and have yet to figure out where 6 pax would put all their feet....

[IHL]

In January 2003 there was a fatal AS 350 B2 accident in Canada. The pilot was very experienced but lost control.
The conclusion from the Transportation Safety Board of Canada (TSB):

Causes and Contributing Factors
1)After experiencing a hydraulic system failure, the helicopter departed controlled flight and crashed while manoeuvring for landing. The reason for the departure from controlled flight could not be determined.
...
Full report :A03O0012

http://www.tsb.gc.ca/en/reports/air/2003/A03O0012/A03O0012.asp

[oldbeefer]

My instructor said 2 min without HYD every day will take care of any workout needs you have!! - but if you fly at the recommended speed of 60kts or so, it takes no effort at all. Landings are simple if a 10kt run-on is possible. Harder work if a hover is essential, but still possible for all but the feeblest pilots.

[3top]

beefer,

you are right, "workout" will need some other than 60kt speed.
We did hover landings and take-offs without hydraulics.
Instructor said, it is not recommended, but one could even ferry a helo to the shop if necessary (wityhout hydraulics).....

3top

[JimEli]

>
We did hover landings and take-offs without hydraulics.
Instructor said, it is not recommended, but one could even ferry a helo to the shop if necessary (wityhout hydraulics).....
<

Factory school operating in direct violation of the RFM? We might have found the root of the Astar's reputation for misbehaving hydraulics.

[3top]

Jim,
don't get me wrong or get the instructor in trouble.
Certainly the RFM says "no", but there is a lot of things that say "no" for legal reasons, that where okay before.
You may not believe it, but there are places you cannot repair a ship, because it is not accessable, but by helo. If there is one onthe only place to land you are done.
You might walk in, but if it is possible, get a ferry permit and fly it out....
(if you know the airframe can do it without a - further - problem)
3top

[Devil 49]

No flipping way that I'm taking an AS350 off the ground with malfunctioning hydraulics, period. Yes, in my experience, it's flyable with the boost off, but that's entirely beside the point. Emergencies are best handled on the ground, and compromised controls qualify as an emergency. Taking off into an emergency is STUPID, even if it's not illegal where you are.
Really sorry about grounding the aircaft a few days hike away from the road, but that's what I'm paid to do- make the hard and inconvenient calls. This aircraft regularly kills pilots with hydraulics failures, and I have no wish to find out why.

Rant mode off...

[JimEli]

>
(if you know the airframe can do it without a - further - problem)
<

Interesting slippery slope you’re landing on there. At what point, do you start to follow regulations?

[Finnrotor.com]

Interesting slippery slope you’re landing on there. At what point, do you start to follow regulations?

Yep. Looks like another accident just waiting to happen..:uhoh:

[3top]

Jim,
I am following regs to the point, we are talking emergency here, are we?
In my end of the world the authorities take the regs rather serious, but they do allow for emergencies, even when not airframe related.
E.g. There is no VFR/single -night flying for helicopters here, cut-off is Sunset. However I (and other helo pilots) had various times atended to medical emergencies on the ground and the returnflight ended definitely after hours (up to 2.5 hrs into the night) - no legal problems in these cases, mostly not even a report requested - no one here dares to declare a medical flight and land on the only hospital helipad in town for fun!

Devil, maybe you haven't been in a "situation" before, I was - luckily without any emergency at this point.

Wet day - put geologists onto a gravel bed in a river (about 1 foot) above the water, at that the precise spot, you cannot get away, unless you are a supreme free climber (or Spiderman) or have rafting equiment with you.

One of them is his 60s and has a bad hip.

Before the rotor came to a stop I realised that the river was rising (again).
I restarted immediatly and recalled the 2 scientist (taking water samples).
By the time I was ready for take off, I had the skids under water.... (about 2 min, whatever it takes to start an R-44 and load 2 pax and get fully engaged and to 100% rrpm)

If you are on the spot, you will try the lesser of 2 evils.

Given my (so far very little) experience in the B3 and the practised maneuvers during the transition course, I would definitely try to take the helo to a different spot.

Also the Canadian accident mentioned earlier in this thread may have had an electrical problem, that could have rendered the hyd switch on the collective (hydr. cut-off) un-usable - as mentioned in the report.

If I experience a hydr. problem in the air and deal with it in a manner to keep flying (switch off HYD on collective) and the bird is flyable, where is the problem, except having selected the wrong place to land the first time.....



3top

[Devil 49]

3top-
I started flying in '69 as a US Army helo pilot, 1st duty assignment- VietNam. My callsign while there is the source of my forum name, "Devil 49". I've been in a situation or two.
I'm not new to the type being discussed, either. Over the years, I've gotten something on the order of:
5000 hours (over 15 years) in the TwinStar/AStar;
approx 30,000 landings in the airframe;
Flown EMS in it for the last 6 years, and I've seen people die in it;
And I've had the occasional failure in the type. It's my favorite of all the helicopters I've flown.
I'll repeat, I've been in a situation or two, and I would so leave the broken aircraft to fend for itself, so quickly, that it's not funny. Sorry about the couple days hike in or hoist down to fix it, but...
As to passengers and any life and death scenarios imaginable, that's an individual call. As we say in EMS, I won't kill 4, 3 or even 2 trying to save 1. Add the fact that taking passengers aboard a disabled aircraft is a violation of professional trust.
One is casual regarding airworthiness at one's own peril. It tends to become a fatal habit, in my experience. This aircraft regularly kills pilots dealing with hydraulic problems. I have to believe that in all those events, there's been at least one pilot who was as good as I am. It can happen to me, if I let it.

[3top]

D49,

thanks for the numbers.
I pull the ferry permit off the list (wasn't a smart one to begin with - if I can get the permit, I can get the mechanic....).
No intentions to load anybody on the machine, they would be there long before it happened.
Note taken about airworthiness - was there, gott'n away with it. Am rather very intolerant when it comes to airworthiness today (I am also working for a different company now....).
Certainly hope to never have to put my emergency training to the real test (did that before, I hope once is enough....).
Details, I am only assuming a simple belt failure - no pressure - switches working - bird keeps flying controlable....
If hydraulics freeze/lock/jam you can't do anything than prey anyway...
I envy you for your flight training, though not for your overseas tour after.

Got enough "learned from this" experiences without the heavymetal air....


Fin and Jim,

mentioning slippery slope:
.. did it ever happen to you, that you arrived on a site and it turned out to be to steep or slippery? What you do then with HYD out, but flyable?

I know we can dream up scenarios all day, but you know what? Actually not a bad idea, because it does make you think - what if?

Thinking about "interesting" landing-sites I ran into, I do ask myself what I would/could do if an emergency would occur/or had occured on approach...

The river here is for real, just so happened the helo was okay (... and has a "no action needed" HYD failure mode).

I had other scientists repeatedly on such a remote pinacle location, there IS NO walk out ..... (D49, where I live you are lucky IF they find you, and IF the winch works....)


enough,...
3top

[Madocus]

http://www.aaib.dft.gov.uk/sites/aaib/publications/bulletins/may_2006/eurocopter_as350b3_ecureuil__g_bzvg.cfm

If this link works it will take you to the AAIB report which explains that one of the factors of this accident was the HYD TEST button being left depressed, thereby leaving the tail rotor accumulator depleted, during hydraulic failure training.

[3top]

The training procedure calls for pressing the HYD-TEST, Student reacts by slowing to about 60kts and switching off HYD on the collective. Instructor switches HYD-TEST back on (up-position).
My instructor prefers NOT to use the HYD-TEST button in the air, except for the loss of TR-control procedure.
He will only push the Warning-lights-button and call out "Hydraulic Failure", Student reacts by slowing to 60 kts and switching off collective HYD.

Reasons:
a) If correctly tested at start-up the accus should provide enough pressure and time to slow to 60 kts, so this should be transparent, whether the HYD-TEST is pressed or not.

b) Training is to learn procedures and habits. By NOT using the HYD-TEST with HYD-failure training he avoids a possible confusion when a real one hits.
He does emphazise to "Never touch the HYD-TEST in the air, except for TR-control loss!"
(First round of practise I forgot about it and would not know how to procede with the TR-control-loss procedure, but for sure I had it marked "to never touch HYD-TEST in the air....")

c) If for any reason the HYDs suffer any damage or incident while practising HYD-failures, the TR stays controlable and a non-HYD landing should be a non-event. With HYD-TEST pressed or locked for any reason (CB popped??), it would become a TR-control-loss + HYD-loss approach/landing = very heavy and very tough...

3top

[Jack Carson]

The fact is that there have been far too many hydraulic system related mishaps in the AS-350 series. Having been checked out in only the B2 and B3 models my experience is some what limited. But my experience tells me that any extended flight in the AS-350 with the hydraulic system inoperative can be very fatiguing to a point where control may be compromised. While attempting not to sound sexist I cannot help but believe that most women pilots would have difficulty controlling the aircraft after experiencing a hydraulic failure. This may have been evident in AS-350 mishap in Apache Junction Arizona in 2005. The following was copied from a previous post on PPRUNE concerning hydraulic servo transparency. Something has to be said about an aircraft design where even the hydraulic system is not capable of over coming flight load in some situations.

I am really surprised that the AS-350 series was successfully certified with published control forces so high. Even after a single system failure (Hyd or Servo transparency) the resulting control forces must not exceed those outlined as Arm strength N (lb) Design criteria levels in Chapter 14 of the US Federal Aviation Administration Human Factors Guide. Table 14.5.2.1 of this guide clearly states the maximum force for a right hand, lateral control motion to the left should be no more than 6 to 8 pounds. This is far in excess of what is published in the AS-350 RFM. US designed and certified aircraft are required to meet these requirements. These standards were applied when Sikorsky included viscous cyclic control dampers in the H-53 Series to insure that in the event of a control damper bind it could be easily over ridden within the force limitations of the aforementioned table.

[I-IIII]

I everyone
I am pretty new in this forum .........but not in helicopter operations,I spent 22 years fly and maintenance on 350 most on B2 and B3 series and I never heard so much **** like this.Fortunatly some of you has a brain in the head,Hyd failure means failure!!!!!!red ******* light!!!!!! In B3 series the force on controls without hyd is about 25kg each side in normal helicopter weight.When is at max gross weight is more than 25kg.So I read lot of you very brave ....takeoff whitout hyd just to see if is possible or just to show that the instructor is a good pilot...........the instructor shold be carrefull to teach that never show a student something that is not wrote on FM and never wrote it on a forum where u can find pilots with a lot of experience and pilot with few Hrs and of course everyone take an example .This is the most stupit aeronautical mentality.Red light gives u the time to land immediately and safely.Thats it no bull****.So in every condition red light go down immediately no metter where u are.This is the mentality to save your life.And the biggest **** is to flight back the hely from the field without Hyd.Hyd failure is tested for a short fly time and if u not believe me check the dimensions of the controls bar fron the control to the Hyd sistem.Flight with FM in the brain not under the sit.

[Anthony Supplebottom]

I-IIIIIIII, what an interesting post.

Not.

[Jack Carson]

The fact is, a failure of the belt that drives the hydraulic pump will result in the illumination of the hydraulic warning light and an immediate loss of hydraulic pressure. The accumulators are provided to allow for sufficient control of the aircraft to reduce airspeed to 65 KIAS. From this point forward control has to be maintained while overcoming between 15 and 26 lbs of lateral cyclic force. This is not trivial and is part of the justification for going to a duel hydraulic system in EC-130 and having the option for duel hydraulics in the AS-350 series.

[FH1100 Pilot]

Jack, in the second paragraph of your post #41 (which I think you were only quoting) there is some information I believe to be incorrect.

The AS-350 is certified in the U.S. under 14CFR27.

When it comes to a flight control activated by hand, 27.397 would appear to apply. This allows for 100 pounds (45kg) of force to be needed to move a control fore-and-aft, and 67 pounds (30kg) of force to move the control laterally.

This is, as you note, quite high.

[AnFI]

... er so the AS350 has hydraulic failures , pump drive belt failures , many crashes - NY roof landing on video great example ...

BUT R66 !! oh no ! has a hydraulic system which has none of those problems (like the R44) but can't get certified - because it's against the certification rule....

Shurley shome mistake methinks .... clearly the rules are broken

Must the R66 have hydraulics as bad as an AS350 to get certified - I hope not!
Change the rule - or get the interpretation, "extremely remote", right...

... this is arse-about-face

[Jack Carson]

FH1100 , 14CFR27.397 pertains to the structural integrity of the flight control system. Should a gorilla enter the cockpit and move the controls then the controls should not break, bend or fail at loads up to those listed. The numbers I sighted are from an FAA human factors report. 14CFR27.141 addresses the control of the aircraft under normal flight conditions and 14CFR27.695 address control after a failure. Both paragraphs are sufficiently vague and list no specific numbers. I can send you a copy of the Human Factors report if you would like.
Jack

[FH1100 Pilot]

Oh Jack, I'm familiar with the HFDG. I'm just hazy on how you're interpreting the numbers. I get different ones from that chart. In any event, the HFDG does not appear to be regulatory.


http://i603.photobucket.com/albums/tt114/n206th/14521.jpg

[Shawn Coyle]

The AS-350 series were certified in the USA under a bilateral agreement with France. The FAA did not certify it to meet Part 27.

[FH1100 Pilot]

Well I don't know about all that, Shawn. All's I know is that there is an FAA Type Certificate Data Sheet Number H9EU (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/47e99eb745b78d8586257a79004946e6/$FILE/H9EU%20Rev-21.pdf) that covers the AS-350 and EC-130.

Below is an exerpt from it. Look under "Certification Basis." I took this to mean that the AS-350 was certified under Part 27. No?

http://i603.photobucket.com/albums/tt114/n206th/AS350TCDS.jpg

[Shawn Coyle]

Since the machines were not initially built in the USA, the FAA would not have done the certification. Bilateral agreements are the way this is overcome.

[FH1100 Pilot]

Well that's not really the point, is it Shawn?

*MY* point is this: Jack Carson wondered how the AS-350 ever got certified with its hydraulic-off control forces so high? He referenced an FAA design document and said the FAA calls for a maximum of only 6-8 pounds of force to be applied to a control (which seemed pretty low to me). He implied that this maximum is/was mandatory. But if you look on the chart that Mr. Carson referenced, look at movement #6 and we see that the recommended force is defined at 71 to 78 pounds. Perhaps Mr. Carson mistakenly referred to this chart and really meant to reference something else.

But even this is all moot because the FAA's Human Factor Design Guide is *not* mandatory, *AND* our U.S. FAR part 27 defines no maximum amount of control pressure. And whether the FAA did the original testing or not, the AS-350 has a U.S. Type Certificate and the certification of the aircraft is based on...wait for it...FAR part 27.

So. Are the hydraulics-off forces in an AS-350 high? Most certainly. Are they unacceptably high? Perhaps for some pilots, yes although no pilot worth his salt will ever admit to it. How did the AS-350 ever get certified with such high control forces? Easy! There are no standards.

For comparison, I had an hydraulic failure once (recently) in a Sikorsky S-55. It made the Astar seem like a piece of cake. Foolishly (and arrogantly) thought I could just fly back to my LZ and land, but abandoned that plan pretty quickly when I realized how much effort it was taking just to fly the bitch. It was horrible. Sometimes you have to admit to yourself that it's not worth it trying to be the hero. So I found a level patch of land and put 'er down. It flew so poorly that I was realistically prepared for it to "not work out so well" (i.e. roll over on landing). It did not...not due to my superior airmanship, but rather sheer dumb luck.

Dang, give me back my JetRanger!

[Jack Carson]

FH1100
The S-55 first flew on 10 Nov 1949. One would wonder exactly what specifications it was designed built and certified to. I would hope that the system (FAA and manufacturers) became a little more intelligent over the years. By comparison the AS-350 was designed, built and certified in the 1970s in Europe. The AS-350 was brought into the US under the bilateral agreement between the FAA and the European authorities cited by Shawn. It was only recently that the AS-350 was certified for complete manufacture in the US. Up until then all aircraft were manufactured, flown and certified in Europe then disassembled and shipped to Texas where they were reassembled for completion and delivery. The question then is: Could the AS-350 have met the entire spectrum of US certification requirement outlined for helicopters in the 1970s? I hope that Shawn may be able shed more light on this subject. To answer FH1100, YES I believe that the B206L-4 Long Ranger is a great machine and under appreciated.

[AnFI]

"Equivalent level of safety in lieu of direct compliance"

That's how you certify something which is safe but the rules are wrong - like R66 hydraulics ... which are excellent

Also protectionism is short sighted and leads to worse product and terminally uncompetitive companies which go out of business - many examples (eg Islander etc etc). this regulatory nonsense needs to be fixed asap.

[Grenville Fortescue]

I should like to hear the FAA's take on this matter.

Even better if they would review this matter with a view to requiring Eurocopter to demonstrate (practically) the safety of the AS350's un-boosted flight control capability in all flight modes.

[RVDT]

§ 27.397 Limit pilot forces and torques.
(a) Except as provided in paragraph (b) of this section, the limit pilot forces are as follows:

(1) For foot controls, 130 pounds.

(2) For stick controls, 100 pounds fore and aft, and 67 pounds laterally.

(b) For flap, tab, stabilizer, rotor brake, and landing gear operating controls, the follows apply (R=radius in inches):

(1) Crank, wheel, and lever controls, [1+R]/3 × 50 pounds, but not less than 50 pounds nor more than 100 pounds for hand operated controls or 130 pounds for foot operated controls, applied at any angle within 20 degrees of the plane of motion of the control.

(2) Twist controls, 80R inch-pounds.

[Amdt. 27-11, 41 FR 55469, Dec. 20, 1976, as amended by Amdt. 27-40, 66 FR 23538, May 9, 2001]

Type certificate for the 350 was issued to FAR 27 Amdt 1 thru 10

This stuff is probably over 40 years old. It is addressed on some of the later models.

But hey -

caveat emptor |ˈempˌtôr|
noun
the principle that the buyer alone is responsible for checking the quality and suitability of goods before a purchase is made