S61 at Humberside, offshore engine failure! [Archive]

NavyTorque

15th Oct 2008, 18:59

I was flying the S61 in question on final approach to Energy Enhancer - A "Jack Up" rig approx 85 miles NE of Humberside.

We had just commenced the turn onto finals at approx 400' 70 kts when a classic bang bang bang (although much quieter than I had always expected) was heard with the associated torque split and then fluctuations.

It was recognised as a surging number 1 engine (T5 was subsequently seen on HUMS as having peaked at 945 prior to it's shutdown) and the aircraft was turned away from the rig and the situation was dealt with as per the many times we have all done it in the sim and OPCs LPCs!

Company traffic that heard our Pan Call offered to divert to us because obviously we were only able to climb very slowly and were not showing on Anglia Radar. Also it is always nice to have a comfort blanket.

I can post the weights, fuels etc if any one is really interested - but will need to get out the flight log!

These events always get you thinking - no matter how experienced you are; Most of the return trip to Humberside was flown at 70 kts due to limited power. We had a ground speed of about 60 kts - now IF the winds had been what they were last week - then our ground speed would have been 25kts.

As always - perhaps the real heroes of all of these incidents are the radar controllers - and again on this occasion of particular note was how calm and professional Anglia Radar were:

1. No hassle after acknowledging Pan Call until we had sorted out aircraft.
2. They responded to the offer from the other company helicopter with a DR estimate of our position pending a GPS update from us after we had sorted out the problem.
3. RT was spot on - not too much, not too little and completely calm and accurate.

I telephoned Anglia Radar afterwards to say thank you to the obviously "Experienced Controller" to be told that he was a controller "Under Training" - hopefully he passed that assessment!!

On speaking to the Passengers afterwards they said they were still 100% confident in the S61 and perhaps even more so now that it had been proved to them that the old girls CAN fly on on engine even at perhaps the most critical point of flight!

Thank you for reading this.

RT

helimutt

15th Oct 2008, 21:48

Thanks for your input. Always nice to get the info first hand.
I always wonder how it will go if it ever happens to me. :hmm:
The fact I also fly out of Humberside makes me think the chances of it happening again out of the same airport in the near future are slim, so I should be okay for a while at least!
Glad to see it all worked out like it should, no matter if you are the competition.;)

I see the 61 was flying the next day. Quick engine change and Roberts your fathers brother!:ok:

Outwest

15th Oct 2008, 21:52

Thanks very much for the info Navy Torque and a big pat on the back to you and your crew. :D

I agree with your pax, the old girl can still hold her head high.

Would be interested in the weights and OAT and if you had fuel jettision available, if not to much trouble.

Leading Edge,
well mine was 10 years later and a lot less exciting....cruise flight, inbound to base with a light load......actually a non-event.

AviatorAtHeart

15th Oct 2008, 23:26

A rotary enthusiast speaking here...

Great to hear everything worked out well. I was really curious about the landing tough - did you guys have enough power to bring it to a hover and land or was a run-on required ?

Cheers..

[email protected]

16th Oct 2008, 05:46

Aviator - since they flew back at 70 kts due to limited power, I think it very unlikely that there would be enough to hover on and the safest profile (in case the other one quit) would be a high level VMC transit followed by an autorotative approach to a flare recovery and running landing.

Navy - are they P and W engines in the 61?

ScotiaQ

16th Oct 2008, 06:00

Crab,

No they are General Electric CT 58-140.....and usually very reliable.

unstable load

16th Oct 2008, 06:06

Crab,

General Electric CT58-140-2 most likely or the 140-1 maybe.

Outwest,

I have not worked in UK but the ex North Sea ships I have worked on all had fuel dump fitted. I believe it is a UKCAA requirement.

Well done again, Navy Torque!

helimutt

16th Oct 2008, 06:58

AviatoratHeart, just to let you know, from reliable sources who witnessed the run on landing, it was 'textbook'!! :ok:

PS Twice a year, this sort of engine failure training, and lots of other stuff, is carried out for exactly this reason. Comforting to see that it works.

JimL

16th Oct 2008, 07:45

Crab,

high level VMC transit followed by an autorotative approach to a flare recovery and running landing.That was tongue-in-cheek wasn't it?

Jim

cmwangs

16th Oct 2008, 08:01

Well Done, Son!!:D:D:ok:!
CMW

simfly

16th Oct 2008, 13:37

Well done Navy torque....

ps, check you pm's!

Variable Load

16th Oct 2008, 14:02

Crab,

Quote:
high level VMC transit followed by an autorotative approach to a flare recovery and running landing.
That was tongue-in-cheek wasn't it?

Jim

Everything Crab says is a joke, isn't it :E

NavyTorque

16th Oct 2008, 15:40

Yes aircraft had fuel jettison available - elected to keep what we had since we could maintain a gentle climb if required and only engine exceedance reported on GOOD engine was a slight prolonged T5 exceedance - we assume that this is due to the possible slight difference between what is displayed on the gauge and what is recorded by Hums and because we were using nearly all the T5 availble to us within Intercon. We flew back at 690-695 Intercon limit T5 - torque was in region of 100% most of way home

Engine question answered by others.

Detailed fuel, HUMs figures - well feel free to PM me for fear of boring you all.

No not all S61s on North Sea have dump - the BIH cab currently working Donegal Doesn't have it! (yes it does work the North Sea at times).

You are right - there was not enough power for a hover landing.

Regards

NT

gribbs

16th Oct 2008, 15:42

I sincererly hope that Crab's comment wasn't meant to be taken seriously. Hopefully nobody will heed that advice; I can't think of a more dangerous way of making a single engine approach in a '61.

NavyTorque

16th Oct 2008, 15:48

Sorry but the aircraft wasn't flying agian the next day - it was G BDIJ the ex SAR machine, we took the passengers out the next day - we carefully briefed the oncoming pax at the rig in case they were overly concerned.

On approach back to Humberside we heard a whistling 1R that sounded very benign - like loosing a strip of blade tape on the Sea King. The noise then stopped and became a very slight 1R whistling with NO associated effects on the controls or feedback or change in flying characteristics or power required etc.

Upon inspection on landing we had lost the complete underside of one of the blade pockets - ie you could see the spars and formers!!! That happened much to anyone else???

Is the good Lord trying to tell me something.

NT

JimL

16th Oct 2008, 16:18

One further point before all become weepy-eyed about the capability of the S61; if 'Navy Torque' was flying it and his account is accurate (as I assume he was and it is), an engine failure at 70kts (very close to Vy) and just about 500ft is as benign as it can get.

Without discounting the trauma of any engine failure; there should have been very little droop and, providing the topping was correct (which it seldom is), the power should have settled with little speed adjustment and there should have been 150ft/min climb performance at the intercontingency power.

An engine failure at below 35kts and closer to the rig might have yielded a different outcome.

Regardless, the crew are to be congratulated on performing the drills as required and recovering the aircraft in one piece to Humberside.

Jim

[email protected]

16th Oct 2008, 16:22

If you have had a single engine failure in a twin engined machine, you are now a single engined helicopter with poor performance carrying fare-paying passengers. In case the remaining engine quits (and you don't know exactly why the first one stopped) you should fly a profile that allows for that to happen and still permit you to safely enter auto and carry out an EOL.
Now this might not be possible due to weather but I would love to hear the arguments against this course of action when day/VMC.

And no, this is not tongue in cheek.

JimL

16th Oct 2008, 16:42

Crab,

There are profiles in the RFM should there be an engine failure; these are practiced during the OPC and the pilot is recommended to follow them.

If the reliability of the engine is 1:100,000/flight hour (as most of them are), the probability of one of two failing is 2:100,000/flight hour; the probability of one failing followed by the second (from independent causes) is 1 in 10,000,000,000.

Most pilots of twins do not (have to) practice autorotations; if they do they are never flown to the ground (there is no need and it exposes the aircraft and crew to unecessary damage).

Because you are an articulate and experience aviator, most on this site pay attention to what you say; for that reason alone, you should be guarded and considered about any advice you give.

Jim

Bertie Thruster

16th Oct 2008, 18:00

What Crab suggested is standard military practice after single engine failure on a twin.

ie after a single failure fly the machine like a single and be prepared for the other engine to stop. (especially if dodgy fuel upload or heavy precipitation is suspected in the cause of the first failure.)

I've only had one single engine failure in a twin . The other engine stopped about 2 minutes later.

skadi

16th Oct 2008, 18:21

In case the remaining engine quits (and you don't know exactly why the first one stopped) you should fly a profile that allows for that to happen and still permit you to safely enter auto and carry out an EOL.

I agree with that statement for the enroute phase of the flight, but ( even in my military training ) the final landing should be carried out according to normal OEI landing profile, no autorotation at all! ( and we practised ARs a lot)

skadi

Spanish Waltzer

16th Oct 2008, 18:35

Have to agree with Skadi. I have enjoyed the priviledge of receiving and then later giving instruction within mil flying circles on single engine failures whilst flying a twin. Whilst I can see up to a point the concern crab raises I do not recall carrying out autorotative approaches during OEI training.

Crab - I would be interested to hear if the CFS training has changed or is this your personal viewpoint?

helimutt

16th Oct 2008, 19:10

Nice to see the old 61's still required in service. Just to cheer CRAB up a bit, it would appear that the AW139 is now, for the time being, day only for SAR and the 61 is standing in. Now that has to put a smile on his face!

[email protected]

16th Oct 2008, 19:57

Helimutt - that little snippet hadn't escaped my notice and you are absolutely right:)

Jim - an auto to a flare recovery (ie the hover taxy) should be a basic skill of any helicopter pilot but especially those flying twins since it is the closest they will come to practicing an EOL. One of the first things you learn in helicopter flying is how to autorotate and for very good reason. If you say this is hazardous then the training is wrong because having to complete a real EOL with no idea of the profile is far more hazardous. I am well aware of the arguments about the fatigue that autos impose on the airframe but profit (ie extending the aircraft TBOs) shouldn't affect safety.
If you want to let probability decide for you then be my guest - I am always ready for a single engine failure in my line of work so why shouldn't I be ready for the second one to let go as well (quoting probability in this case is like trusting statistics)

Spanish - the military teach a variety of techniques for single engine approaches but most are within a tactical ie low level remit and the basic SE approach will be from 500' or below trading speed for power until 10% (to pluck a figure from the sky) below your max available to reduce the groundspeed and hence the ground run (useful where space is limited ie not at an airfield). Airmanship, in a non tactical environment, can be superimposed on that teaching and lead you to surmise that floating around at low level on one engine could be a less than ideal scenario - the first thing I encourage people to do is climb to give you time and options.

roundwego

16th Oct 2008, 20:51

According to Crab's logic (see his first post on this thread), in my single engine helicopter, every flight has to terminate with "an autorotative approach to a flare recovery and running landing" just in case the engine fails - What is this guy on?

Well done to the crew of this flight. I have circa 19,000hrs (99% twin) and am still waiting for my first engine failure. Does that mean the odds for me having an engine failure are much higher and you should avoid flying with me?

Fareastdriver

16th Oct 2008, 20:53

Crab

Navy - are they P and W engines in the 61?

As unstable load said, CT58s, of which the RR Gnome is a licence built version. I thought you would have known that.

helimutt

16th Oct 2008, 21:00

Roundwego, I would imagine that statistically you'd be the most likely to have an engine failure. 19,000hrs.? You been sleeping in them or something? :D

Whirlygig

16th Oct 2008, 21:02

Does that mean the odds for me having an engine failure are much higher and you should avoid flying with me?
No, the odds are the same; engines don't know who is operating them and statistics have no memory!

Cheers

Whirls

HeliComparator

16th Oct 2008, 21:50

My worst nightmare - having Crab as stude on an EC225 conversion. Can't get a word in for the "when we were in the military we did it like this..." (pauses to tie hankerchief with red spot round brow, enters auto on simulated single engine finals whilst pressing cyclic trigger and muttering dagerdagerdager under his breath). This is of course because the military are only trained to kill people, they are not trained nor allowed to carry fare paying passengers.

But sorry JimL I just have to pick you up on one point - the probablility of a second engine failure after the first one failing is not your further 1 in 100,000 or whatever, its greater than that because now you are running the remaining engine much harder than its used to. Nevertheless its still not that high and certainly doesn't warrant Crab's kamikazi dive.

HC

arandcee

16th Oct 2008, 22:42

"This is of course because the military are only trained to kill people"

:rolleyes:

Bravo73

16th Oct 2008, 23:25

19,000hrs.? You been sleeping in them or something? :D

Probably 'just' flying offshore for 20+ years. Might only be early 40s by now (if started at 18).

Brian Abraham

17th Oct 2008, 00:20

would be a high level VMC transit followed by an autorotative approach to a flare recovery and running landing.I can understand where crab is coming from. Had an engine failure at CDP on a rig take off which was accompanied by a massive explosion as the turbine let go. Once safely in the climb my major concern was had the "good engine" suffered in any way (it was that massive an explosion). A mayday had been put out, course set for home and altitude gained so that a comfortable auto could be carried out should need be. On land fall ensured that a suitable paddock was available for an auto and made a lever on the floor approach to the runway with a run on using available power (about 30-40 knots). The only reason for the steep approach in this case was the thinking I don't trust the "good" engine due possible inflicted damage from the failed engine. The line of thinking was primarily influenced by the massive explosion when it let go. I had plenty of previous experience of single engine landings flying the line (precationary shutdowns, particularly when the 76 was new to the industry) and in those cases flew the text book flight manual approach. While Speechless Two is correct in his "requirements of a civilian crew to abide by both the Flight Manual profiles and the requirements of the Company Operations Manual" at times you need to fall back on your judgement and experience and cut the cloth to suit the situation.

Practice autos (power recovery) were a feature of our regular base checks (six monthly) and one intrepid C & Ter on a one off basis would purposely "forget" to put the throttles up in the flare so you ended up with a surprise full blown auto to the ground (S-76).

roundwego, you are well overdue :p The above was my first full blown chew em up and spit em out failure. About 18 months later had an identical failure in the same aircraft but now the other engine. Although the mechanics of the failure were exactly the same (high power at take off and turbine letting go) this time it was accompanied by just a quiet almost inaudible "pop". And that was at about the 19,000 hour mark. Good luck and may the Gods continue to smile on you.

gnow

17th Oct 2008, 06:05

Well Done Navy Torque and welcome to the club. In my 14 000 hrs plus of flying S61N,(total time now 19 000hrs) I had 6 engine failures on S61N including a reject at 20500 lbs from the airfield near to the CDP for a modified Group A departure (300ft/45 kts). They used to say I have arse luck but after so many arse luck incidents, I tend to be very careful and cautious!
You were right..and I have always given that a thought. On one engine at intercon power you are lucky to get close to 80/90 kts. in a bad headwind situation, we may not have enough fuel to reach home.
I had one incident which even Sikorsky did not managed to explain.We were cruising along happily at 2000 ft (and condeming the management as usual!) when suddenly the cross hatch symbol appeared on the fuel shut off valve. That means it has gone to a CLOSED position sudddenly(All this while the valve is physically opened). Within a minute the engine flamed out. Now all our manuals says that the fuel shut off valve will "remain in its last energised position no matter what happens..eg total loss of electricity).
The rule of this game is always try and be a good boy scout..BE PREPARED!

JimL

17th Oct 2008, 07:16

Helicomparitor,

Accepted - in that case make the probability of the second failure 1:1,000 and the probability of one followed by the second (from independent cause) will still be 1:100,000,000.

Crab,

Clearly you are conditioned by your military experience; those of us who left the military and then flew as civilians are conditioned more by that experience.

Examine your proposition; the engine failure has been contained and the helicopter flown back to an airfield. On arrival at the airfield, the helicopter is kept at altitude until an autorotation is initiated.

Now consider the probability of an engine failure (using Helicomparitor's probability and the minute spent on finals 1: 60 x 100,000,000) against that of successfully completing an autorotation with (up to) 19 passengers on board.

Add to that the knowledge that there are far more accidents associated with training for autorotation than the real thing and that most engine failures in flight leading to autorotation do not result in outcomes without damage and the risk assessment is now in perspective.

Jim

oleary

17th Oct 2008, 07:35

In the early days of the Okanagan Helicopters Beaufort Sea & High Arctic ops we always ran 26 pax in the 61 with no F/A. I understand they are now down to 19.

In Edson we ran 29 (OKB?) pax with the 61L and 26 pax in the N. The destination at the mine was Hd 8500'+ in the summer.

No fuel dump on any of these a/c, but they were mostly shorter legs, so we didn't carry much center tank gas. We still used 20,500 for T/O though (or 22,000+ lbs external load), mostly.

Note 1: The Canadian East Coast was much different and more like the North Sea but with less wind and more fog.

Note 2: I was never good enough to pull off a full-on auto with this kind of load in a 61.

Generally, for an OEI approach we used a fairly flat rotor-disc-loaded (but with a little bit of power in reserve for Momma) and ran the the puppy's on.

Note 3: If you let the IAS drop below about 42 knts (at high GW) - she will fall like a stone.

Keep her above that and she's perfectly happy on one engine.

ps Been there

[email protected]

19th Oct 2008, 07:32

JimL - you make it sound like an autorotation is a. dangerous and b. difficult - even at MAUM it is a straight-forward manoeuvre, especially straight in to a runway.

Consider your proposition - one engine has failed (for an undetermined reason) and you elect to fly a normal approach to running landing on your runway. During the 60 seconds on finals (I think it would probably be a bit longer), the second engine decides to let go as well and you crash into the undershoot trashing the aircraft and injuring/killing the pax. What exactly is your defence? I was following the RFM and anyway we don't practice autos because it's not good for the airframe?

I'm not saying this is the only way of doing it or that it would be possible or practical in all situations but I offer it up as an airmanship consideration to those who might not have considered this course of action because they have only been conditioned by their civilian experience.

I am clearly not alone in my thinking vis Bertie and Brian so maybe those who were so quick to condemn out of hand should maybe pause for thought.

Roundwego - in the many hours of single-engine helicopter flying I have done, the consequences of an engine fail were seldom far from my mind but as long as you kept out of the avoid curve (H-V curve) you could operate safe in the knowledge that you could enter auto and make an EoL.

A heavy twin full of pax on a single engine would have a much bigger avoid curve and so the procedure for flying a SE approach should be modified to accommodate that.

Troglodita

19th Oct 2008, 10:23

Crab,

Consider your proposition - one engine has failed (for an undetermined reason) and you elect to fly a normal approach to running landing on your runway.

Keeping it simple (No Vtoss/Vy/Vbrocs etc.)

We at Bristow (and CHC I believe) irrespective of twin type fly Commercial Air Transport (CAT) take-off and landing profiles to either Performance Class One (No exposure in the event of a power plant failure) or Performance Class Two (possible exposure for minimum period) depending on space available for take off or landing. We calculate and adhere to decision points (TDP and LDP) for each profile.
In the event of an engine failure in flight we would in almost all circumstances elect to fly a normal approach to running landing on your runway.

Until LDP we are well outside the SINGLE ENGINE H/V curve and at LDP (for example in a Bell 412 at 100 feet rad alt and 40 kts IAS) reach the leading edge of the SINGLE ENGINE H/V curve - we maintain 40 kts to 50ft rad alt then reduce speed and altitude by flaring for a running landing staying under and clear of the curve throughout the profile.
With both engines performing impeccably or following a failure we avoid any exposure!

Hopefully you will now appreciate that we have absolutely no requirement to attempt an autorotation which may be a "piece of cake" (as Biggles and your good self would probably say!) to Chaps of your calibre but to most of us other mere mortals normally takes several attempts during Sim rides before you avoid the "red death" since we have little opportunity for practice during our day jobs.

Even in the event of a tail rotor control failure where normal options are either a full autorotation or high speed run on landing - I personally advocate a mid option which is a 1000 ft/min powered descent at 40 knots (approximately) to the left or right side of the runway (depending on rotor rotation direction) followed by a gentle flare and rapid throttle shut off (to a last minute auto landing) at approximately 30 feet to a short run on remaining at all times on the runway. Try it next time in the Sim (doesn't matter which type) - it works and has a much higher survival rate than either of the other options!

Trog

Toohey29

19th Oct 2008, 12:58

Just wanted to echo the congrats of others to the two guys concerned, was a pleasure to escort you guys in even if it did seem to take forever at 70kts!

[email protected]

20th Oct 2008, 05:55

And I thought we were talking about an S61 full of pax not a 412 Trog - I suspect the SE HV curve is a good deal bigger than the 412s.

Your defence is that you don't do it because you don't practice it - my answer is then go and practice it. You shouldn't be flying pax around if you can't do autos.

An ex BA 747 training captain told me that senior pilots were having to hire light twins to keep their flying skills going - their sim training was more systems failure and management thereof and they never got to fly the real aircraft because they were always full of pax. Their pure flying skills eroded in the same way you are bemoaning yours going, simply because no-one mandates you do GH every month (not profitable). Do you really think that is safe or sensible?

Many people believe that what can be done in the sim will work in real life, especially with TR failures, without understanding that the sim (any sim) isn't modelled accurately for TR malfunctions - you need the data from the real aircraft in the real configuration for that, not a best guess from interpolated data.
You carry on convincing yourself that you know better than evryone else but you'll find that 40 kts isn't sufficient to keep the nose straight with no TR and you can't expect the pitot-static system to measure it accurately anyway, especially with the high levels of sideslip involved.

Troglodita

20th Oct 2008, 07:40

You carry on convincing yourself that you know better than evryone else

Crab,

Forgive me please for offering an opinion with my limited experience!:oh:

After leaving the RN in 1979 with only 2500 hrs of Seaking time including SAR I have obviously in the last 29 years and a further 14,000 hrs (including over 6500 on S61N North Sea and Far East) not yet amassed sufficient experience to comment or offer suggestions to an Aviator of your calibre. As a TRE/IRE/SFE I obviously believe that everything that I teach in a Simulator is absolutely accurate and I have failed over the years to notice the differences in observed simulation scenarios between simulators built by different companies.
My suggestion that we follow Well Established Approved Civilian procedures obviously offends you and what do we know anyway?
My presumption that descending at 1000 ft/min at associated low power setting will greatly reduce the need for anti torque and permit almost any helicopter to fly straight without as much bank applied up until the point that you enter autorotation as you flare is obviously bollocks and I would be much better in full auto.

I will crawl back to my cave dwelling immediately.

Trog

[email protected]

20th Oct 2008, 08:55

Trog - I guess I hit a nerve there then.:) At the point where you have to start telling me how experienced you are and all the things you have been to defend your position, your argument is weakened.

By your own admission the accepted procedures for TR fail are either auto or high speed run on yet you advocate something different - how many TR failures have you had to base this technique on? And have you ever prcatised this technique with zero TR thrust in a real aircraft?

BTW do you mean single engine HV curve (ie when you are on one engine and it fails) or do you mean the Safe single engine envelope (where you are on two but will still fly if one goes)?

The military have never seen fit to produce a SE HV curve for a twin, maybe it is different in the civvy world.

MINself

20th Oct 2008, 09:55

A very interesting thread... for my tupence if I still had an engine working on a ME type and on the balance of probability of the remaining engine also failing isn't it safer and easier to stick with a tried and tested SE profile and run the aircraft onto a runway rather than decide to go for an auto, which you may not have practiced for a while? I guess thats where the military have the advantage when it comes to not having to worry about trivia, like costs!
I guess there are numerous variables to this argument no least the aircraft & AUM, crew recency, airfield and weather... in this case the crew got home safe... :D

Farmer 1

20th Oct 2008, 09:59

Troglodita,

Why can't you accept it? You're wrong.

You, and the manufacturers, and the operators, and the CAA, and the FAA, and the...

helimutt

20th Oct 2008, 11:45

All Hail Crab. All Hail Crab!!
Just kidding guys.

:E:E:E:E:ok:

Aser

20th Oct 2008, 12:57

Trog,
I like your thinking about the event of a tail rotor control failure, but this sentences about OEI lading confuses me.

In the event of an engine failure in flight we would in almost all circumstances
Quote:
elect to fly a normal approach to running landing on your runway.

Until LDP we are well outside the SINGLE ENGINE H/V curve and at LDP (for example in a Bell 412 at 100 feet rad alt and 40 kts IAS) reach the leading edge of the SINGLE ENGINE H/V curve - we maintain 40 kts to 50ft rad alt then reduce speed and altitude by flaring for a running landing staying under and clear of the curve throughout the profile.
With both engines performing impeccably or following a failure we avoid any exposure!

I may be not understanding your post, are you telling me that staying out of the H/V you are safe in case the last engine fails in short finals? that curve in the 412 RFM doesn't mean your are safe to do an auto, it's just the profile to achieve a safe lading with OEI onto a prepared surface, I'm sure you know that, but the issue here is the landing in OEI condition.

As crab says
BTW do you mean single engine HV curve (ie when you are on one engine and it fails) or do you mean the Safe single engine envelope (where you are on two but will still (ACHIEVE A SAFE LADING) fly if one goes)?

I can't remember a safe single engine H/V curve in the 412 RFM.

Regards
Aser

Troglodita

20th Oct 2008, 17:00

Farmer

Why can't you accept it? You're wrong.

You, and the manufacturers, and the operators, and the CAA, and the FAA, and the...

You are right - it's amazing how we survive.

With both engines performing impeccably or following a failure we avoid any exposure!

Absolute CRAP - would you agree with: -

With both engines performing impeccably or following a failure we reduce exposure to an absolute minimum!

BHT-412-FM-4

1-10. HEIGHT-VELOCITY
The height-velocity limitations are critical in the event of single engine failure during takeoff, landing, or other operation near the surface (figure 1-4). The AVOID area of the Height-Velocity diagram defines the combinations of airspeed and height above ground from which a safe single engine landing on a smooth, level, firm surface cannot be assured.

The graph at 1.4 is titled "Height velocity diagram (OEI)"

I can't remember a safe single engine H/V curve in the 412 RFM.

I didn't actually say "safe single engine H/V curve" but I can see where I caused confusion.

Re the T/R failure thing - think it through - the last 30 or so guys that I have discussed this with and asked to play with the profile in 3 x different Sims agree that it is at least worth considering as an option!

Trog

Artifical Horizon

21st Oct 2008, 09:26

Is Crab suggesting an autorative descent over an airfield and then converting to a running landing? A full blooded auto to the flare recovery does seem a little drastic old boy!!!!

[email protected]

21st Oct 2008, 14:23

Trog - you said SINGLE ENGINE H/V curve twice and the argument that accompanied it clearly tried to refute my assertion that the 'normal' or 'approved' or 'RFM' single engine approach puts you firmly in the avoid curve (I will call it that to avoid confusion).

You can call me as many names as you like but at least be man enough to admit when you are wrong.

Artificial Horizon - I believe the RN still do autos to a running landing and having flown the profile on a CFS visit to Malaysia it is a very simple and safe procedure, especially since you still have one engine to cushion the landing just like at the end of a normal SE approach. The big difference is that if the other engine quits at ANY stage during the approach, you are already perfectly setup for your endorsement-winning EOL. Not so for the 'normal/approved/RFM' profile.

HAL9000

21st Oct 2008, 15:37

Crab's original post read:

'...the safest profile (in case the other one quit) would be a high level VMC transit followed by an autorotative approach to a flare recovery and running landing.'

If by safest it is meant the profile that provides the highest likelihood of a successful outcome in the event of the second engine failing, isn't Crab right?

Could those of you who disagree with him elaborate on where the stages of his profile become more dangerous than the other ones suggested.

Thanks,

HAL

Troglodita

21st Oct 2008, 17:19

Crab,

I did admit without reservation in my reply to Aser that I was wrong in my highlighted statement which incorrectly asserts that there is no exposure in the event of the remaining engine failing. I admitted it was Absolute Crap.

I did say single engine H/V curve twice - I will say it a third time - the H/V graph in the Bell Flight Manual is titled: -

"Height velocity diagram (OEI)"

I think that a One Engine Inoperative H/V diagram and a single engine H/V diagram are one and the same for a machine with 2 engines!

Strangely enough I don't refute your high level transit part at all (basic airmanship) and if (a HUGE IF) we were given sufficient time (and Company and Client) permission to hone our autorotative skills to the point where we could guarantee a "greaser" every single landing I would agree with that your suggestion would reduce exposure even further than our existing profile.
The latter is unfortunately never going to happen - I am painfully aware when carrying out recurrency check and training on both the Sim and the helicopter of general poor skill levels of otherwise excellent medium to large twin drivers when it comes to autorotations.
We have the facilities and requirement for our 206L4 & 407 offshore pilots in Nigeria and the GOM to carry out full engine offs to the water during annual recurrency training in Louisiana - We use a Bell 206 on fixed floats. This is excellent value and after a couple of days, a 180 degree engine off auto from 80 knots and 400 feet downwind becomes a routine event. I would love all Crews to attend this training annually but the perceived safety of the twin and the cost of providing this training precludes this in the so called "Real World" that we operate in.

Once again - our standard laid down Class One profiles are designed to keep us out of the OEI/Single Engine H/V curve at all times to minimise exposure. If we can't achieve this we are flying a Class Two profile which may place us in the H/V curve for short periods - e.g. Operating to a confined area or post commital point to an offshore platform.

Apologies for my rudeness but maybe you have been told once in a while that you can be exasperating.

Trog

[email protected]

22nd Oct 2008, 08:40

Trog - :ok:I know I can get peoples backs up but that is often the problem with the written word - it is open to interpretation by the reader and often the tone and content/intent of my posts is lost on some. Back to English school for me then:)

Fareastdriver

25th Oct 2008, 08:12

Crab.
There are vast differences between military and civil flying and main one is the people in the back. A situation where you have an engine failure and fly a profile to guard against the other failing is correct under certain circumstances, but not all. I have flown close it once when I returned to Aberdeen with BOTH fuel filter lights on which is as close as I would like to be to a double engine failiure. I cannot think of another reason for doing it when you have a contained engine failure or no common source reason for the first failure.
Military crew or passengers do not worry overtly as to what is going on because they are a disiplined force and will obey and listen to instructions or explanations. Civilian passengers are not quite the same thing remembering that we are in the EU and some of their English may not be up to scratch. Any time that something does not go to plan, especially in a perceived dangerous envirionment such as an offshore helicopter, will cause serious concern or even panic.
It is hard to believe that during the time of the BV234 most of the Shell passengers believed that the British Airways Helicopters claim of ‘twin rotor safety’ meant that a Chinook could fly with just one rotor operating. Even now the vast majority of offshore passengers believe that if both engines fail on any helicopter the rotors stop and the whole lot plunges to earth. Should you have an engine failiure, especially a noisy one, those behind you will think that they have moved a big step closer to the grim reaper.
You will have little success explaining OEI performance on the way back because passengers are notorious for not understanding something they do not expect over the PA, even more in a noisy cabin. You will have even more trouble trying to explain autorotative performance. Should you approach the airfield at a perceived high level, drop the lever for your initial auto and the good engine throttles back, you will have a very good chance of at least one major cardiac arrest within your passengers.
There are tens of thousands of single engined helicopters flying around this world and a multi down to one engine is in the same league. Some twins, at a typical landing weight returning from offshore, have higher power/weight ratio on one engine than some single engined examples have total. Singles do not fly an autorotative approach profile so why should a twin on one?
Avoid curves for twins are so that they can recover on one engine. Avoid curves for singles are so that they can recover. If something happens to be in the way, that’s tough. Good singles pilots try to avoid that. The present procedures, as used by every civil operator and tested and certified by the manufacturer, has always worked so why fix it.
Taking the argument to the logical conclusion if a Boeing 737 suffered an engine failure, on your advice it would approach at 1,000 feet until within gliding range of the runway, cut the remaining thottle and stuff the nose down for a glide approach and landing.
I can see the headlines now.

902Jon

25th Oct 2008, 10:32

To continue Fareastdrivers argument,with our litigous society, if one flew a profile that was outside of the recomended Flight Manual or SOP from the emergency section of the Ops Manual, you can be sure that one (at least) passenger would suffer from some sort of post-traumatic stress. Compensation about never being able to fly in a helicopter/work offshore again, from a smart lawyers angle, could amount to a huge amount. And of course, where one went, others would surely follow.

The opportunity to practice autorotative approaches, without passengers on-board, would be minimal, so the chances of a successful one in an emergency would accordingly decrease.

[email protected]

26th Oct 2008, 06:30

As I said earlier - I am not advocating it as the only way to do business but highlighting it as an alternative which, if you do do subsequently lose the second engine, does not leave you unprepared or poorly positioned for the EOL.

Fareast - I understand your position entirely re pax but, in the unhappy event of a twin on one engine losing the second one on finals, I would much prefer to cause the pax some unease than smash them all into the undershoot - I can see the headline now.

It is a fact that statistically you are very unlikely to lose one engine, let alone 2 and the procedures employed and recommended reflect this. But in a situation (as originally detailed on this thread re S61) if you don't know why the first engine has failed and you have any suspicion that there may be collateral damage to the second (or maintenance issues or a host of other reasons) then you would not be exercising your airmanship and captaincy fully if you did not at least consider placing yourself in a flight regime that allowed a safe (if scary) outcome should the second one let go.

As I said before - not being able to do autos because you don't practice them is not an excuse or defence in this case - this is a major safety issue, you should have mandated GH training to ensure your flying skills are up to the level that your fare-paying pax expect them to be.