Caco's trial helicopter flight.....

[Cacophonix]

I agree with all that FD2 says. I've never experienced a true FADEC machine but I put this forward for consideration.

Our domestic iron has a fail safe where after a certain amount of time of remaining static it switches itself off to prevent any accidents. I continually try to get Mrs C16 to turn the power to the iron off if she is leaving it even for a few minutes but she tells me it's not a problem as the safety cut out will turn it off if she forgets - as she often does. Wrong attitude! It's the same with FADEC - it takes the protection out of the pilot's hands but at the end of the day FADEC can fail and the pilot must monitor everything and not rely on the almost infallible safety systems.

Re "Putting too heavy a boot full of right rudder pedal in while raising the collective in the hover and watching the engine RPM rise towards the red line", as it is an American design, on the R44 putting in left boot in the hover will result in even more power demand on the engine than putting in right boot. French and Russian machines are the opposite to Amercian and British helos due to the different direction of the main rotor, ie right boot results in more power demand.

Accept and agree with your note on the R44 ref. anti-clockwise main rotor and the need to counter the torque and opposite movement of the helicopter fuselage/body by putting in left pedal which increases the amount of tail rotor thrust (thus requiring more power) and causes the helicopter to yaw to the left to counteract the toque. I believe my mistake was forgetting that I would need less power on the right pedal, over pedalling and inadevertantly pulling on the collective at the same time which caused the revs to rise higher than I would have wished (I didn't breach the red line but realised that I could if I continue making silly mistakes like that).

So many ways to cock it up it seems.

Caco

[Cacophonix]

One 'FADEC' story to frighten Caco - at CFS RAF Little Rissington, several years ago, a BAE Jetstream 201 was taxying quite happily when FADEC shut down both engines..............

I assume the pilot pulled the throttle from taxi to idle (< 24% N1 or whatever it is for BAE Jetstream 201) and instead of idling the engines simply cutout? Put me out of my misery Boac, tell me what happened!

Caco

[Boac]

Dunno, Sir - Jetstreams were a mystery to a fast-jet pilot I remember there was a hoo-hah and I think the beasts were grounded.

[Cacophonix]

Dunno, Sir - Jetstreams were a mystery to a fast-jet pilot I remember there was a hoo-hah and I think the beasts were grounded.

SAA Airlink lost a Jetstream back in 2009 after engine failure and wrong engine shutdown. Pilot died sometime after the accident and FO and 1 cabin crew member and one person on the ground seriously injured. I remember feeling for the Captain who had been caught up in another engine failure previously.

https://www.news24.com/southafrica/news ... t-20091008

Airlink Jetstream.JPG (87.83 KiB) Viewed 715 times

https://en.wikipedia.org/wiki/Airlink_Flight_8911

http://www.caa.co.za/Accidents%20and%20 ... s/8692.pdf

Not FADEC related but still. Reason my interest in your Jetstream FADEC point was piqued is because Lucas Aerospace provided the FADEC for the Jetstream at one stage and a company I worked for subcontracted for blah, blah, blah...

Caco

[Boac]

Was only trying to frighten you, anyway . I suspect whatever problems were there have long been eradicated.

[FD2]

In my rush to assure you that digital control of your engine(s) will make like a lot easier than these awkward co-ordinations that you have to master at this early stage, I forgot to say that it can also cause problems! Our six-monthly base checks would always have 'problems' created by the instructor such as engine freezes, or engine runaways up or down. Nothing is 100% reliable and though these things improve over the years they can never be completely 'safe'. I ended up sitting in the Clyde with 3 crew and two passengers in a Sea King (only for about 3 or 4 minutes) because a computer shut down one engine (back in 1975 and Rolls Royce swore it couldn't happen ) and also had to fly an S76 back to Norwich on one engine when an Nf overspeed sensor malfunctioned and shut an engine down. A Sea King was lost off Portland when the crew mis-identified which engine which had had a runaway. Computers do, however, make aircraft control a lot easier, just don't ever relax into thinking they are foolproof!

[CharlieOneSix]

A Sea King was lost off Portland when the crew mis-identified which engine which had had a runaway.

Oh the joy on a dark winter's night offshore (in a Bell 214ST) trying to work out which engine had the runaway and which one has done its job and is trying to maintain 100%NR. The torque needles split - was it a runaway up or a runaway down? Was it a low side failure and the other engine has accelerated to maintain the NR or was it a high side failure and the other engine has run to idle trying to maintain the NR?

Solution: If NR initially tends high, then the engine with the higher MGT (Measured Gas Temperature) is the engine with the failure. If NR initially tends low then the engine with the lower MGT is the engine with the failure. It's SO easy to revert to your single engine days and assume, rather than diagnosing, that the faulty engine is the one with the low indications.

Once you've decide what the failure is then:
With a high side failure - wind associated throttle back on high side engine and maintain 10% below good engine torque. Low side failure - put associated low side engine into manual throttle control and maintain 10% torque difference as above. The reason in a low side failure that you have to put the engine into manual control is that in normal flight both engine throttles are fully open but the fuel flow is maintained by the digital engine controls at the correct level to maintain 100%NR.

I'm off on a tangent with this, Caco, as none of that will affect you unless you go for a twin rating in years to come but as FD2 says, it shows that digital engine controls in a twin engine helicopter can make life difficult on occasion.

[FD2]

And as you say C16, made all the more interesting by being offshore on a dark winter's night!

[Cacophonix]

A Sea King was lost off Portland when the crew mis-identified which engine which had had a runaway.

Oh the joy on a dark winter's night offshore (in a Bell 214ST) trying to work out which engine had the runaway and which one has done its job and is trying to maintain 100%NR. The torque needles split - was it a runaway up or a runaway down? Was it a low side failure and the other engine has accelerated to maintain the NR or was it a high side failure and the other engine has run to idle trying to maintain the NR?

Solution: If NR initially tends high, then the engine with the higher MGT (Measured Gas Temperature) is the engine with the failure. If NR initially tends low then the engine with the lower MGT is the engine with the failure. It's SO easy to revert to your single engine days and assume, rather than diagnosing, that the faulty engine is the one with the low indications.

Once you've decide what the failure is then:
With a high side failure - wind associated throttle back on high side engine and maintain 10% below good engine torque. Low side failure - put associated low side engine into manual throttle control and maintain 10% torque difference as above. The reason in a low side failure that you have to put the engine into manual control is that in normal flight both engine throttles are fully open but the fuel flow is maintained by the digital engine controls at the correct level to maintain 100%NR.

I'm off on a tangent with this, Caco, as none of that will affect you unless you go for a twin rating in years to come but as FD2 says, it shows that digital engine controls in a twin engine helicopter can make life difficult on occasion.

I did have a multi engine fixed wing rating in the past and had the pleasure of doing the turbine conversion (single and twin) back in my pomp in the early 90's so the basics are not alien to me. As you say, and at my age, I doubt I will ever have need of, or, more importantly, have the money, to go down the twin turbine path in helicopters, so all this stuff is academic but it is still fun, and very interesting, to ponder the issues and learn a bit more from you chaps (in theory at least) anyhow!

Caco

[Woody]

Some info for Caco

https://www.bbc.co.uk/news/av/business- ... elicopters

[Cacophonix]

Absolutely beautiful day on the south coast today...

Bücker Bü 131 Jungmann.JPG (25.15 KiB) Viewed 614 times

A gaggle.JPG (72.09 KiB) Viewed 614 times

More Egg Beating.JPG (66.28 KiB) Viewed 614 times

Caco

[Fox3WheresMyBanana]

Had a stuck RPM on the F3 once due to a FADEC failure. It didn't put up any captions (which it should have done). Noticed it about 2 minutes later when I next selected burner and one nozzle didn't open (which I always checked). The rpm was stuck at 85%, with throttle waggling having zero effect. Nor was this the first time an F3 had had a similar FADEC failure with no warning captions. RTB with engine shutdown 10 miles out for SE landing was the drill (presumably in case the FADEC decided to do something else weird on short finals).
That's the problem with modern electronic / computer systems, they are so complex that it's impossible to guarantee that the failure warnings will activate correctly, then you've got a right mess to sort out whilst the brain digs deep for systems knowledge and you try to work out whether failures are real or not, and what the possible consequences are. And the Flight Reference Cards can be more hindrance than help sometimes. I recall an accident where the nav had seven different drills to follow, and not being from Norfolk he only had 5 fingers on his spare hand to use as markers.
I think there could be some merit in a turn-just-about-everything-off button, for situations where the crew would rather just fly the damn thing and put it down on a piece of tarmac, a kind of Tiger Moth Mode.

[Cacophonix]

Into the territory of autorotation now and have some questions about auto rotations and running landings. First silly question I guess is what is the life of non wheeled skids grazing along the runway or even grass? Even with the gentlest landings, the friction must play havoc with the underneath of the fragile looking R44 skids anyway? It seems that the R44 is a huge jump above the R22 in this area though with enough rotor inertia to make the latter stages of touchdown less stressful and gentle touchdowns a possibility without preternatural piloting abilities being required. As a fixed wing type I am going to have to ignore the tendency to want to pull back unnecessarily on the stick in close proximity to the ground lest I bump the boom on the ground or, worse, with the rotor!


Given all this new info it seems that the R44 needs to be watched like a hawk in autorotation least one over-rev's the rotor and thus judicious use of the collective is necessary. I guess better high revs than no revs but 90% is perfect.

Caco

[Cacophonix]

Into the territory of autorotation now and have some questions about auto rotations and running landings. First silly question I guess is what is the life of non wheeled skids grazing along the runway or even grass? Even with the gentlest landings, the friction must play havoc with the underneath of the fragile looking R44 skids anyway? It seems that the R44 is a huge jump above the R22 in this area though with enough rotor inertia to make the latter stages of touchdown less stressful and gentle touchdowns a possibility without preternatural piloting abilities being required. As a fixed wing type I am going to have to ignore the tendency to want to pull back unnecessarily on the stick in close proximity to the ground lest I bump the boom on the ground or, worse, with the rotor!


Given all this new info it seems that the R44 needs to be watched like a hawk in autorotation least one over-rev's the rotor and thus judicious use of the collective is necessary. I guess better high revs than no revs but 90% is perfect.

Emergency-R44.JPG (19.23 KiB) Viewed 549 times

Caco

[G~Man]

First silly question I guess is what is the life of non wheeled skids grazing along the runway or even grass? Even with the gentlest landings, the friction must play havoc with the underneath of the fragile looking R44 skids anyway?
Caco

One can buy skid shoes that are made of carbon steel that last for years and hardly wear down at all. We have them on our Huey and Jet Ranger for doing touch downs. And please do not do full downs to grass---always go to a hard surface, the skids are designed to spread slightly and will dig in on dirt and your risk dynamic rollover.

[Cacophonix]

First silly question I guess is what is the life of non wheeled skids grazing along the runway or even grass? Even with the gentlest landings, the friction must play havoc with the underneath of the fragile looking R44 skids anyway?
Caco

One can buy skid shoes that are made of carbon steel that last for years and hardly wear down at all. We have them on our Huey and Jet Ranger for doing touch downs. And please do not do full downs to grass---always go to a hard surface, the skids are designed to spread slightly and will dig in on dirt and your risk dynamic rollover.

Thanks for that info G~Man. I will definitely heed the advice about grass, thanks.

The folks training me lost an R22 to dynamic rollover about a year ago in a real emergency that resulted in an emergency auto-rotation into a wheat field. Pilot and passenger walked away and the insurance
people coughed up.

Caco

[CharlieOneSix]

Caco - whilst I hear what Gordy says and appreciate his reasons, you're going to find it a bit difficult not to do engine off landings on grass when you are learning at an airfield which has no hard runways. When Bristow ab initio pilots were trained at Redhill in the 60's and 70's the Hiller UH-12C was used and later in the 80's+ some R22's were the ab initio trainers. Redhill still only has grass runways for EOL practice.

I wouldn't want to hazard a guess at how many practice EOL's I've done to grass airfields in a variety of skid equipped helicopter types but as ever, the advice of your instructor is king.

[Cacophonix]

Both runways at Headcorn are grass and neither is flat or as smooth as a bowling green so I suspect I am on the cusp of learning the art of running landings onto grass although all normal landings to date have been made on the hard surface in front of the hangars. I guess I can heed the G~Man's good advice insofar as being aware of the danger of digging in. I have read FAA material on the art of auto-rotation and they advise against grass as well but as you say C16 I will be advised by my instructor who demands the highest standards and is very safety conscious and if he says that I should practise on grass then grass it shall be.

Caco

[Cacophonix]

As a fixed wing type I was discussing a legendary pilot and instructor at my local airfield, Neville Browning, who took fixed wing PFL's to a whole new dimension by ensuring his students actually landed on the fields of his farm which was some 4 miles from where I live so that he could pop in to check on some aspect of the cows' well being while the bemused students would be instructed to clean the mud from the underside of the wings. What the CAA thought of this modus operandi is unrecorded.

Neville, of course, was also famous for flying with his dog and flying inverted circuits at the airfield s in his Zlin and eventually he succumbed to life on the edge and gravity when the main spar broke on the Zlin (as they often did) in his 70's at an airshow somewhere. Apparently he was an excellent instructor and they don't make them like him anymore. He is still discussed in local pubs by the farmers here with great affection.

I guess the approach to in air emergencies in helicopters is a little different because you can and in some cases, must, get your behind on terra firma ASAP in that your wings are moving parts of a mechanical device and if the rotors on top and behind cease turning you are entering a whole new world of pain.

I tend to try and learn by heeding the advice of men like C16, FD2, Gordy et al who have been around the rotor hub more times than I will ever eat hot dinners and it is great to be able to learn from their accumulated wisdom garnered over varied and fascinating professional careers.

Occasionally one can learn from better men who succumbed to gravity's malign force. Men like the legendary South African helicopter pilot Bees Marais who maybe delayed just a fraction too long in dropping his Bambi Bucket, probably for fear of hitting ground crew, and getting onto terra firma when a warning light came on in his Huey while fighting a fire at Cape Point. The fact that the helicopter maintenance regime was found to be at fault was ultimately the primary cause of this accident.

The SACAA report focused on Marais’s crash, saying the seasoned pilot took off from Newlands with the Bambi bucket, used to carry water, suspended below the chopper.

On his way to the fire he reported via radio that he had a “tail chip detector warning”, and was advised by another pilot flying nearby to land as soon as possible.

Marais replied, saying he would land at the nearby helicopter support vehicle, but shortly afterwards broadcast his “mayday mayday mayday” distress call.

“The helicopter was observed to rotate in a clockwise direction, making abrupt movements,” the report said.

Marais died in the crash.

The report suggested that clear guidance material on the positioning of Bambi buckets be supplied to flight crew.

“It is recommended in the interest of aviation safety that they consider introducing a standard whereby Bambi buckets be placed inside the cabin area during positioning flights.”

The report said although it could not be proven, it was believed the bucket being positioned outside Marais’s chopper could have affected the handling of the helicopter.

There were signs that the bucket had collided with the chopper’s rotor blades.

https://www.iol.co.za/news/south-africa ... rs-1971977

Bees Marais.jpg (64.62 KiB) Viewed 512 times

Caco

[FD2]

Caco: I might suggest that the tail rotor (gearbox, presumably) chip detection indicated an imminent failure. I don't know what type he was flying that day and if there were any secondary indications, e.g. tail rotor gearbox oil temp, to confirm the chip warning. Also I don't know how long he would have taken to reach the helicopter support vehicle and if any delay would have affected the outcome, but it certainly seems as if the aircraft then had a tail rotor gearbox failure - hence the uncontrolled rotation and subsequent crash. An underslung bucket may well have gone anywhere as the aircraft rotated and possibly contacted a main rotor blade.

The autorotational characteristics of various types of helicopters depends on their design and any airflow you can get around the tail pylon as you keep speed on during the descent and crab downwards. The flare will probably be messy and may not be survivable, not matter how skilled the pilot is. We used to think that the 6ft 'plug' in the S61N fuselage would make it less 'controllable' after a tail rotor failure than the S61A/Sea King as there was more fuselage forward of the main rotor head which might lessen the effect of the tail pylon. A very experienced test pilot once told me that above all it was important to lose as much forward speed as possible - more important than rate of descent - as too much forward speed would probably mean the aircraft falling apart after impact, but a high rate of descent was possibly more survivable as fuselage structure below absorbed the impact.