Hydraulics failure- helicopters

[pilot_tolip]

Who's got any real world experience with in-flight hydraulic failure? Not simulated/training hydraulics off - but sudden real-world failure. What were your experiences with the failure of hydraulics? I'm interested to hear your experiences so I can learn from you. Thanks

[SASless]

It all depends upon the aircraft, it’s systems, and where you are re landing sites.

[Gordy]

Who's got any real world experience with in-flight hydraulic failure?

Had hydraulic failure in an Astar in an out of ground effect hover at 1,000', me plus 6 passengers over Napali coast in Hawaii back in 2002. 27nm from Lihue airport. Had the front seat pax hold the pressure on the cyclic to save my arm strength for the landing 30 minutes later. I did tell my pax what was happening, (kinda hard to hide when the horn goes off for 25 seconds). Flew back, did shallow approach to a "slow" quick stop flare to the ground. Not a huge deal---just do what you do in training. Mine was caused by the failure of the A/C belt which then took out the hydraulic belt.

Take aways: Always declare an emergency as you will get priority handling and always take it to a hard surface so the skids can slide if needed without digging in---I touched down from a hover--but I have been trained to do that.

[timprice]

Its not how you have been trained! its what's in the Flight manual, I am fed up with people thinking they are better than the manufacturer, follow the flight manual (hopefully that was how you where trained as per flight manual)
Once had hydraulic runaway on one servo in Jetranger many moons ago, cyclic kept motoring aft, just switched off hydraulics and landed.:ok:

[Thomas coupling]

Utility hyd failure in a S61.
The MGB cooler fan drive belt(of which there are two) - snapped and severed a utility hyd pipe running alongside. The hyd supplied the undercarriage.
Had 3 MAJOR problems:
1. Back of the cab filled up with hyd mist expelling @ 3000psi!! As you know, hyd mist is a carcinogenic, so all the back seat crew had to come up front as we vented the rear of the cab.
2. No U/C. So RTB and hovered for 15 mins while we blew the gear down and dropped a crewman out the back to pin the gravity fed U/C before landing.
3. No MGB cooling. Flew the last few minutes of the sortie with the gauge just shy of max (115 degrees from memory). Caption lit during our hover.

[Gordy]

Its not how you have been trained! its what's in the Flight manual, I am fed up with people thinking they are better than the manufacturer, follow the flight manual (hopefully that was how you where trained as per flight manual)


Errrr, the flight manual is created for people working from airports---I normally see an airport a few times a year, the rest of the time I operate from a pad or field in the middle of nowhere, hence we train for the conditions we will likely encounter. Sometimes the flight manual does not keep up with reality due to "potential litigation". Clearly I need to find a higher horse.

Look at all the accidents that occur doing Hyd off in an Astar---if only they were taught correctly.

[Flyting]

Had one in a Bell 205 IFR @ 12500' somewhere over Nigeria on a ferry flight.
With horrific noises coming from the back we elected to make an emergecy desent and land in an opening in the bush. Made an inspection (with rotors running) and then left the Hyd off and flew 90min to the next airport. Ended up with a Popeye arm after that!

[GrayHorizonsHeli]

Once I ate too much KFC and while driving back to the city had a blowout of the number 2 seal....Oh wait, sorry, thats a different kind of hydraulics.

[SASless]

I do so love "Cook Book " Pilots....who must lead a very sheltered existence. (Not referring to Gordy of course!)

Flying, On some aircraft I found applying some pressure to the cyclic in the direction you wanted it to move and then letting the feedback pulses to move it for you to be far easier than making like Popeye after a Can of Spinach or Charles Atlas.

The 206, 205 (single hydraulics), 58T and others generally liked that method.

The 58T's Collective used to make me feel like I was carrying the aircraft around in my left hand!

A flying Buddy and I in Tactical Training in a UH-1D had a hydraulics failure and flew the thing back to Home Plate.....the Cyclic was a bit stiff but manageable but the Collective was very...very...very easy up.....and a bugger bear to move down even with two of us grunting and straining against the seatbelts.

In a 206 in Iran.....at a Bush site....had a Collective freeze tighter than the Black Sardine's purse clasp. Fortunately it was at a power setting that allowed for a very slow speed run on landing at the normal parking spot.

I did. have one hydraulic fed cockpit fire in a Chinook that was a bit sporty.

[Gordy]

I do so love "Cook Book " Pilots....who must lead a very sheltered existence.


Me too.....


A flying Buddy and I in Tactical Training in a UH-1D had a hydraulics failure and flew the thing back to Home Plate.....the Cyclic was a bit stiff but manageable but the Collective was very...very...very easy up.....and a bugger bear to move down even with two of us grunting and straining against the seatbelts.

The two Hueys I fly have the same issue, we have played with the rigging but almost impossible to get rid of it....basically have to get the thing to a hover, (higher pitch setting), and then lean all my weight on the collective to get it down.

In training we turn the Hydraulics off in a 150' hover simulating the failure right as you pick up the long line load, and take it straight back down in a Bell product, and use the accumulators in the Astar to get forward speed and bring it back shallow approach to a hover landing----simulating our only "pad" to land on. We use former factory pilots for our outside vendor training---they do it day in day out and really do teach you to be comfortable with the machine.

SAS---as you know I had the stuck pedal years ago----had no clue what I was doing, (former company with no training), but got it down. Have since practiced it every year since and feel confident I would do better now.

For those still reading, I had a wire strike 2 weeks ago and survived, cut a 60kv 3 phase line with the blades on one and the other two went into the wire cutters---FWIW, they do work.

[krypton_john]

For those still reading, I had a wire strike 2 weeks ago and survived, cut a 60kv 3 phase line with the blades on one and the other two went into the wire cutters---FWIW, they do work.

Isch! Gives me nightmares.

[SASless]

Fellows....and Ladies too.....if ever you get near Gordy.....please do rub his shoulder an pray some of his good luck rubs off on you!:D

There's plenty of ways of getting killed in our business....and Wires will straight up kill you!:{

Gordy beat the house big time two weeks ago!:eek:

[Gordy]

Isch! Gives me nightmares.
Me too....

https://abc7news.com/helicopter-strike-on-power-lines-sparked-grass-fires-outage/4354526/

Unlike the article stated, I hit the ones going above me, not the ones I was patrolling. They were not marked and were about 200' off the ground.

I'm not welcome in Calistoga or Middletown anymore after cutting their power for a few hours...:cool::cool:

[PAXboy]

Did the unmarked cables belong to the same utility as the ones you were patrolling? Whose responsibility is it to update the maps given to you and other line inspectors?
Lastly, for those of us that keep away from 60kv lines :eek: where are the wirecutters? They will have to work damm fast!

[SASless]

Ingrates the lot of them.....look how look how much money you saved them on their electric bills!

[krypton_john]

Seems like a line crossing the inspected line is a super risk as you're watching the line you are inspecting and less likely to spot the cross line with which you've been placed in a certain collision course. Nasty combination.

How did the blades fare? Am curious to know how well the wire cutters worked - did you just slice through without feeling anything or ... ?

[EMS R22]

Errrr, the flight manual is created for people working from airports---I normally see an airport a few times a year, the rest of the time I operate from a pad or field in the middle of nowhere, hence we train for the conditions we will likely encounter. Sometimes the flight manual does not keep up with reality due to "potential litigation". Clearly I need to find a higher horse.

Look at all the accidents that occur doing Hyd off in an Astar---if only they were taught correctly.

I agree Gordy. Most of the time I have now where flat to run a machine on to.

Good to practice different scenarios with an experienced instructor.

I too have cut wires with a wire strike kit. Not a scratch on the machine.They work.

[Twist & Shout]

I agree Gordy. Most of the time I have now where flat to run a machine on to.

Good to practice different scenarios with an experienced instructor.

........................

Not without its risks.

https://www.atsb.gov.au/publications/investigation_reports/2017/aair/ao-2017-109/

[RVDT]

And another fatal in the UK 6 months prior to the one in Oz.

G-MATH (https://www.gov.uk/aaib-reports/aaib-investigation-to-as350-b3e-ecureuil-g-math)

[RVDT]

A flying Buddy and I in Tactical Training in a UH-1D had a hydraulics failure and flew the thing back to Home Plate.....the Cyclic was a bit stiff but manageable but the Collective was very...very...very easy up.....and a bugger bear to move down even with two of us grunting and straining against the seatbelts.

Single HYD 205's had an adjustment to the inboard strap fitting so you could take the load off at about mid range Q. Not everyone used to be aware of it and some were pretty hard to fly HYD OFF.
Was a little worm drive arrangement from memory. HYD OFF single hydraulics 205's were hardly noticeable in the cyclic above about 30 knots from memory. Also depended if the blades were swept at all.

[pilot_tolip]

Thanks for the replies and details. Interesting to hear

[Saint Jack]

Many years ago, a 206B on short finals to land on a dock-side when suddenly cyclic and collective go stiff. Pilot managed a decent landing and all was well. Investigation revealed that one (I don't remember which) of the hydraulic system quick-disconnect fittings had not been connected properly and became completely undone, probably through vibration. Simply reconnected properly and all as well..

[Gordy]

The investigation is still on-going---will post more when I can.

[SASless]

Wires are very hard to see no matter how careful you are.

While Cherry Drying in Washington State....I would always do a Recon (Recce) of the field before I flew in it blowing the water off the Cherry Trees.

Despite that....one afternoon with the Sun in the wrong direction....I came scary close to cutting down a set of wires going to a water pump house.

A few days later....two other aircraft hit wires....one being a Fatality.

If you have done utility or ag work with a Helicopter for any length of time.....you probably have had a close call or two with wires.

[albatross]

Had a Hyd failure in a 206. Leak which made it much harder to fly vs a pump fail. (pull the hyd CB to make sure it is not just a switch failure...pulling the CB will restore pressure if it is an electrical problem.)

Had 2 in a Astar. First order of business.. turn off that +*^% horn so you can think.
205...,remember that you should never lower the collective below 35 PSI because it will be a bitch to pull it back up.

[ShyTorque]

Failure of the collective pitch boost system on a Blackhawk can result in a very heavy collective. IIRC, it can push up with the equivalent force of 80lbs of weight. It was certainly enough to lift me out of my seat, even with the leg straps done as tight as I could bear them, it's really a two pilot job to fly it in that condition.

[SASless]

105's and 117's are a delight when it comes to Hydraulic Failures!

Even Cook Book pilots can handle hydraulic failures in them.

[Vertical Freedom]

Had a Hydraulic Failure in a JetBox.......scary on take-off from a pinnacle, but quiet manageable :ooh: Also in a B2 Squirrel.......F.F.F.F damn serious when You only have fuel to go back to the marginal confined H & Your heavy :eek:
Practise, practise, practise & have a plan is the secret to success :rolleyes:

[vaqueroaero]

Last year we had a creeping failure on our 206. You could feel it starting to fail. If you moved the controls fast you would feel resistance. If you moved them slowly you maintained pressure. The problem was that after we had changed various components we thought we had fixed it. But no. It would come out of nowhere. Nothing quite like a hydraulic failure coming off or landing on our mix truck for ag work. We finally ended up changing out the quick release couplings and that cured the problem.

None of the above is written in the flight manual either......

As for wires. Had a few close calls, but so far have not hit any.

[nigelh]

Can’t think of many people I would rather be in an emergency than Tim Price ... he probably has more experience in real flying than most here so ignore him at your peril ! ( I am sure there are exceptions to the rule book on special operations but the pilots doing those generally know what they are doing . Most here are just Sunday vfr flyers and don’t need to be told to ignore their flight manual )

[SASless]

Nigel, You do understand most RFM's are written by Lawyers with some input from Engineers and Test Piots?

RFM's by necessity are a one size fits all approach with its main focus being relieving the Manufacturer from liability.

As most Regulations and RFM's are not etched in Stone....Training has to fit reality and there is not a RFM out there that can accomplish that.

Mr. Price may be very experienced and perhaps meant something different than the way his post came across.

That being said.... training must take into consideration what the RFM has to say about Emergency Procedures but if those procedures do not fit your operation then what do you do?

[ShyTorque]

I was flying in echelon starboard formation with another Puma when the sky a few metres ahead of us suddenly turned bright red!
When hydraulic fluid mist sprayed all over our windscreen I realised what was happening and called on the radio: "Two to Lead, Looks like you've got a major hydraulic failure!"

Reply: "Negative, everything's normal here.....Oo - er! PAN PAN PAN!"

Twenty seconds later he was parked in a field.

[nigelh]

Only he can say , but I think he was saying go with what it says in the manual .... don’t try to wing it and come up with your own idea on the hoof !!!
obviously it is not a one size fits all but for over 90% of pilots and the flying they are doing it will be correct . Are you saying that all that flying by test pilots coming up with the correct actions are not correct and you know better ??? Again I have to repeat myself because many on here just like to show off their skills .....,I am not talking about mountain sites with no flat ground to land on ....I’m not talking about flying sling load over dense forestry . The pilots reading this do not need encouraging to “try out “ what worked for you 20 years ago flying drilling rigs !!! In those circumstances I can well see instructors / high time pilots making their own plan for an emergency.

[SASless]

Now you are being obtuse.

Everyone of us has said training must be done with actual tasks in mind and that the RFM does not always lend itself to those situations.

No one has said "ignore" the RFM.

What we have said is you have to tailor your procedures to fit the need.

If you think any RFM is sacrosanct then why are there Amendments and changes to them over time?

As you note in your own post....not every situation is the same.

If the RFM fits what you are doing....of course you can follow its procedures.

What do you do when there is no Emergency Procedure for the malfunction you are experiencing.....don't you have to come up with a way to cope with that?

Pick a topic....say Tail Rotor Malfunctions and layout all the possible situations.....how thick would the RFM Emergency Procedures Section be if they tried to address each variation of the range of failures possible?

That is why I endorse the notion that the RFM is the guide....not the law.

Are there variations within the RFM as approved by different Authorities?

[nigelh]

It was this remark .....

I do so love "Cook Book " Pilots....who must lead a very sheltered existence.... that I objected to . Firstly you probably have no idea of what he does and what his experience is and lastly you just sound arrogant referring to most of the pilots here as “ Cook Book “ Pilots .
A tiny bit of humility wouldn’t hurt .
of course I agree that the book doesn’t cover everything......

[SASless]

Merely responding to his post.

I did not address my comment to him personally or to "most" the pilots attending this forum.

There are "Cook Book Pilots" out there.....not only in our Industry but throughout all aviation beginning shortly after Man began to fly.

The accident records are full of examples.

[GrayHorizonsHeli]

To tailor a response or reaction to something new, requires experience.
if you have no experience your best bet is to follow a procedure written by someone who had that experience. Hence why flight manuals were created.
they can become legally binding in situations. Dont believe me, go toe to toe with an ornery prosecutor who is holding your actions up to a published and approved procedure.

[SASless]

Ornery Lawyers is why RFM's are written the way there are to a great extent.

But bear in mind....the FAA understands why deviations from the FAR's (which incorporate the RFM) and for Commercial Operators, FAA OPSPECS), are up to the discretion of the Pilot-in-Command during emergencies.

https://www.law.cornell.edu/cfr/text/14/91.3

[Paul Cantrell]

re: hydraulic failures... I'm glad this was brought up. My question isn't about losing boost - I spend so much time teaching loss of boost that it really doesn't worry me (but I don't fly anything larger than a Bell L3 so I might think differently if I was flying bigger aircraft). [btw, Frank Robinson once told me that feedback forces go up as the cube of the blade chord. yikes!].

My question, that I've asked about 10,000 people is, does anyone know anyone who's had a hard-over, i.e. where one of the servos malfunctions and goes full stroke in one direction or the other? Nobody has ever responded in the positive, so either it just doesn't happen, or everybody it's happened to is dead. Anyone here have any input? I usually tell people (half jokingly) that if it happens, the first thing you do is turn of the hydraulics, and the second thing you do is recover from inverted flight.

Can anyone comment from first or second hand experience? I'm assuming nobody is strong enough to fight a servo and that the stick is simply going to go full deflection in some direction, depending on which servo has had the failure?

[ShyTorque]

Some helicopters simply can't be controlled without hydraulics, which is why larger helicopters have two separate hydraulic systems.

[212man]

Failure of the collective pitch boost system on a Blackhawk can result in a very heavy collective. IIRC, it can push up with the equivalent force of 80lbs of weight. It was certainly enough to lift me out of my seat, even with the leg straps done as tight as I could bear them, it's really a two pilot job to fly it in that condition.

Can’t it be turned off? The S92 has a control boost system on al 3 controls, but has an ON/OFF switch on the overhead panel.

[SASless]

212Man,

Are you asking if each Hydraulic System can be turned off individually by a Control Switch?

I cannot imagine this day and time the Blackhawk would have the old S-58T/S-61 AUX/Primary Hydraulic set up as I cannot imagine the US Army not spec'ing a dual/equal system with the ability to shut off a malfunctioning system.

[LRP]

212Man,

Are you asking if each Hydraulic System can be turned off individually by a Control Switch?

I cannot imagine this day and time the Blackhawk would have the old S-58T/S-61 AUX/Primary Hydraulic set up as I cannot imagine the US Army not spec'ing a dual/equal system with the ability to shut off a malfunctioning system.

The UH-1C/M, AH-1G/S had a dual hydraulic system with no provision for turning off a malfunctioning system. There was a Test Switch that was spring loaded to BOTH, you could momentarily turning off a single system to do run-up checks. The AH-64 series has dual hydraulics with no HYD control switches at all. The AH-64 series have no hydraulics off capability, the flight controls simply move an input lever on the servo which moves the spool valve, the servo is bolted to the deck and cannot be manually moved.

[SASless]

Memory serves me the 540 rotor system Charlie Model had accumulators too.....for the Collective system was it?

It was designed to allow for two full cycles of the Collective....meaning from full up to fully down twice.

As it was only fifty years ago I flew the B and C model Hueys......the recollection of those days is getting a bit dim.

[LRP]

Memory serves me the 540 rotor system Charlie Model had accumulators too.....for the Collective system was it?

It was designed to allow for two full cycles of the Collective....meaning from full up to fully down twice.

As it was only fifty years ago I flew the B and C model Hueys......the recollection of those days is getting a bit dim.

The 540 system had an accumulator charged by the #1 system for the collective in the event of a dual system failure. On shutdown you would "bleed" the accumulator by making slow strokes of the collective. For this test you were supposed to get four full strokes (full up, down, up, down). In the event of an actual failure there was no guarantee of the movement allowed and I can tell you that without hydraulics the collective was not movable, you would bend the lever before the blades moved. The AH-1G and AH-1S(MOD)/(PROD) had the same system. The AH-1S(ECAS)/(MC) had an electric pump emergency hydraulic system for the collective.