do all R44s have throttle governors ?
do all R44s have throttle governors ?
If yes, I know at least another one who failed to govern, during final approach. https://burgenland.orf.at/stories/3028185/
Was a good landing though, as all walked away.
Apparently this can happen
https://www.atsb.gov.au/publications...n/ab-2018-082/
Was a good landing though, as all walked away.
Apparently this can happen
https://www.atsb.gov.au/publications...n/ab-2018-082/
If yes, I know at least another one who failed to govern, during final approach. https://burgenland.orf.at/stories/3028185/
Was a good landing though, as all walked away.
Was a good landing though, as all walked away.
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All R44s are governed. However, in my experience, it is one of the less reliable pieces of gear on the helicopter ( true on the R22 as well )
First of all, it's very easy for a pilot to inadvertently override the governor by simply holding the throttle too tightly. We see this all the time in a training environment. Being trained to keep a loose gentle grip on the throttle easily solves that problem. Some people fly with their hand back behind the throttle ( on the metal collective tube ) but I don't recommend that.
Additionally, any problem with the points in the right magneto can cause it to drop offline ( just stop working ) or to cause engine surging. I know several people personally that this has happened to. Depending on what's going on in this case, you may see incorrect engine tachometer indications because the tach works off the same points.
Also, the system can be affected by strong RF signals ( flying close to a radio transmitter ). I've seen this myself a couple times flying near FM radio transmitters.
The R44 has a mechanical correlator which moves the throttle when the collective is moved. The correlator works instantly, and then the governor fine tunes the throttle. At sea level, the correlator on an R44 will maintain RPM within a couple percent, even across large collective movements. At higher altitudes, or with a sick engine, the correlator will move the throttle too much, or not enough, and the governor will have to make an adjustment. Because the correlator moves the throttle simultaneously with the collective movement, while the governor is designed to make relatively slow corrections, rapid movements of the collective will cause momentary RPM excursions. Therefore, as in any helicopter, you should always make slow deliberate collective pitch changes.
Given that the governor on/off switch is right on the end of the collective, easily accessed by your thumb without having to remove your hand from the collective, there's really no reason why a governor failure of any kind should be more than a minor annoyance. People should have a good understanding of the difference between the correlator and the governor, the failure modes of the governor, and how to turn it off and finish the flight making manual corrections to RPM using the throttle. It really is not that difficult a system to master, however some schools don't include sufficient governor training resulting in some pilots who don't fully understand the system.
First of all, it's very easy for a pilot to inadvertently override the governor by simply holding the throttle too tightly. We see this all the time in a training environment. Being trained to keep a loose gentle grip on the throttle easily solves that problem. Some people fly with their hand back behind the throttle ( on the metal collective tube ) but I don't recommend that.
Additionally, any problem with the points in the right magneto can cause it to drop offline ( just stop working ) or to cause engine surging. I know several people personally that this has happened to. Depending on what's going on in this case, you may see incorrect engine tachometer indications because the tach works off the same points.
Also, the system can be affected by strong RF signals ( flying close to a radio transmitter ). I've seen this myself a couple times flying near FM radio transmitters.
The R44 has a mechanical correlator which moves the throttle when the collective is moved. The correlator works instantly, and then the governor fine tunes the throttle. At sea level, the correlator on an R44 will maintain RPM within a couple percent, even across large collective movements. At higher altitudes, or with a sick engine, the correlator will move the throttle too much, or not enough, and the governor will have to make an adjustment. Because the correlator moves the throttle simultaneously with the collective movement, while the governor is designed to make relatively slow corrections, rapid movements of the collective will cause momentary RPM excursions. Therefore, as in any helicopter, you should always make slow deliberate collective pitch changes.
Given that the governor on/off switch is right on the end of the collective, easily accessed by your thumb without having to remove your hand from the collective, there's really no reason why a governor failure of any kind should be more than a minor annoyance. People should have a good understanding of the difference between the correlator and the governor, the failure modes of the governor, and how to turn it off and finish the flight making manual corrections to RPM using the throttle. It really is not that difficult a system to master, however some schools don't include sufficient governor training resulting in some pilots who don't fully understand the system.
Well written Paul !
Over the years I had 3 governor failures (3 different companies) and it's not a big deal. Turn off the gov switch and continue flight, operating the throttle manualy. This is part of the PPL(H) training and should be well understood by any student. Of all the emergencies you train for, gov failure is probably the one that you might have one day.
Regarding the topic: why do you call this a gov failure?? in the german text I can read "er einen Leistungsverlust gehabt" which is a power loss. Lycoming engines are very reliable so an engine failure is highly unlikely, fuel starvation or low fuel with a high angle of bank turn? On final approach you can have vortex ring... The R44 turned due to a plane departing, in the turn you loose lift, rate of descend increases, if the turn was 180 degrees then they had wind from behind etc. Or maybe they ran out of power (slow speed, out of ground effect) and overpitched, unlikely with 3 pob in a R44 unless very heavy pax and lots of fuel.
So there are many possibilities for this crash but I don't think the governor is to blame. If it was the governor, the pilot should have known what to do about it. If suspected malfunctioning, turn it off. So don't do like in the atsb report that was also linked on the top, the pilot left the switch on and operated the throttle manualy. This can result in the pilot giving an input on the throttle and if not held properly, the governor might also give an input, risking an overspeed or low Rrpm (losing lift). Read the POH including the safety notices and follow it. Learn from the mistakes that others made.....
Over the years I had 3 governor failures (3 different companies) and it's not a big deal. Turn off the gov switch and continue flight, operating the throttle manualy. This is part of the PPL(H) training and should be well understood by any student. Of all the emergencies you train for, gov failure is probably the one that you might have one day.
Regarding the topic: why do you call this a gov failure?? in the german text I can read "er einen Leistungsverlust gehabt" which is a power loss. Lycoming engines are very reliable so an engine failure is highly unlikely, fuel starvation or low fuel with a high angle of bank turn? On final approach you can have vortex ring... The R44 turned due to a plane departing, in the turn you loose lift, rate of descend increases, if the turn was 180 degrees then they had wind from behind etc. Or maybe they ran out of power (slow speed, out of ground effect) and overpitched, unlikely with 3 pob in a R44 unless very heavy pax and lots of fuel.
So there are many possibilities for this crash but I don't think the governor is to blame. If it was the governor, the pilot should have known what to do about it. If suspected malfunctioning, turn it off. So don't do like in the atsb report that was also linked on the top, the pilot left the switch on and operated the throttle manualy. This can result in the pilot giving an input on the throttle and if not held properly, the governor might also give an input, risking an overspeed or low Rrpm (losing lift). Read the POH including the safety notices and follow it. Learn from the mistakes that others made.....
For what it's worth, last Sunday also an R44 accident (luckily no injuries) in Belgium - Flanders, following engine trouble/failure(??) a mile before its final destination and a forced landing into a too muddy field, ending up on one side.
A link with some pictures of the scene can be found on https://www.aviation24.be/forums/vie...art=80#p390810 , no further (reliable) factual/technical info available.
A link with some pictures of the scene can be found on https://www.aviation24.be/forums/vie...art=80#p390810 , no further (reliable) factual/technical info available.
,...so what's wrong with that?
thx for all the clarifications!
Apparently there is one place only where one holds the R44 throttle-grip and this is the same spot the governor is actuating against, limited by a slipping clutch.
Thus an R44 governor has to work "against" either too strong a throttle friction setting or too strong a pilot's grip (or both).
Both situations will render the governor effectively "inoperable" as per design!
My assumption what got him is that it was a case of stress induced control-grippitis.
So the governor might well have been working as designed but was overpowered by external force,
which let to RRPM in the 80% range (that is what the pilot quoted to me)
Clearly pilot error, but I'd encourage Robinson to come up with an enhanced "split- throttle grip" design where the pilot's hand normally would grip a section that is non-turning ("pitch only")
and only a small section of the grip's length - say the final two inches compose the actual, twisting throttle function - normally operated by the governor, and undisturbed by the pilots hand.
In case of emergency the pilot's hand would slide forward and overpower the governor. Is that idea feasible? Does such enhancement already exist?
Apparently there is one place only where one holds the R44 throttle-grip and this is the same spot the governor is actuating against, limited by a slipping clutch.
Thus an R44 governor has to work "against" either too strong a throttle friction setting or too strong a pilot's grip (or both).
Both situations will render the governor effectively "inoperable" as per design!
My assumption what got him is that it was a case of stress induced control-grippitis.
So the governor might well have been working as designed but was overpowered by external force,
which let to RRPM in the 80% range (that is what the pilot quoted to me)
Clearly pilot error, but I'd encourage Robinson to come up with an enhanced "split- throttle grip" design where the pilot's hand normally would grip a section that is non-turning ("pitch only")
and only a small section of the grip's length - say the final two inches compose the actual, twisting throttle function - normally operated by the governor, and undisturbed by the pilots hand.
In case of emergency the pilot's hand would slide forward and overpower the governor. Is that idea feasible? Does such enhancement already exist?
Last edited by Reely340; 1st Jan 2020 at 16:04.
Regarding the topic: why do you call this a gov failure?? in the german text I can read "er einen Leistungsverlust gehabt" which is a power loss. Lycoming engines are very reliable so an engine failure is highly unlikely, fuel starvation or low fuel with a high angle of bank turn? On final approach you can have vortex ring... The R44 turned due to a plane departing, in the turn you loose lift, rate of descend increases, if the turn was 180 degrees then they had wind from behind etc. Or maybe they ran out of power (slow speed, out of ground effect) and overpitched, unlikely with 3 pob in a R44 unless very heavy pax and lots of fuel.
He dismissed the media report as nonsense. Tower ordered the plane to hold position and it complied flawlessly.
He admitted that he was at 80ft when he noticed the 80% RRPM.
He had not noticed the horn or the low rpm light, guessing that his ANR headset cancelled out most of the horn's tone.
He'd like the horn to be fed into the intercom and/or a brighter low rpm light, but admitted that he missed the RRPM droop, presumable due to heavy radio communication,
as this was a end-of-the-year GA gathering at a small airfield, with quite some traffic.
So no blame game from his side.
And pls don’t make the light brighter neither, some of us fly at night!
,...though I'd still love to check out an Astro that hasn't...if I could ever find one?
There is no throttle friction in a Robbie.
Clearly pilot error, but I'd encourage Robinson to come up with an enhanced "split- throttle grip" design where the pilot's hand normally would grip a section that is non-turning ("pitch only")
and only a small section of the grip's length - say the final two inches compose the actual, twisting throttle function - normally operated by the governor, and undisturbed by the pilots hand.
In case of emergency the pilot's hand would slide forward and overpower the governor. Is that idea feasible? Does such enhancement already exist?
and only a small section of the grip's length - say the final two inches compose the actual, twisting throttle function - normally operated by the governor, and undisturbed by the pilots hand.
In case of emergency the pilot's hand would slide forward and overpower the governor. Is that idea feasible? Does such enhancement already exist?
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Neither the R22 nor the R44 is difficult to fly without the governor. As Paul already mentioned, the correlator works quite well. Nevertheless, the FAA felt it was prudent to have an operable governor in a low inertia design like the R22 and R44.
Other than training out any tendency to grip things too tightly, this is a non-existent problem not requiring any additional technical solutions. You can override the governor the same way on any governor-equipped piston machine. Indeed, you need to be able to do this in order to enter an auto with a working engine. If you are properly trained you won't have a death grip on the throttle and the governor will do its job. If you do get a low rotor RPM indication the automatic, trained response should be to lower collective and roll throttle on, something that is easy to do if a death grip is already established. And properly performing this latter action is a specific training requirement of SFAR 73 (not the death grip part
). And, if you really feel you must only keep thumb and forefinger on the throttle, simply sliding your hand back a couple of inches, as Paul alludes to, solves that problem as well, although I agree with him in that it is not a preferred habit to get into.
Last edited by aa777888; 1st Jan 2020 at 19:43.
I've hade Bose and Lightspeed ANR and never failed to hear the low Rrpm horn in a Robbie or any other heli with warning sounds. You can even hear the Rrpm's once you get some flying hours.
Part of the startup checklist is check the low Rrpm horn and light.....
Short final, losing ETL, I still have my money on overpitching, trying to stop a high ROD. Sadly at 80ft you don't have much time to lower the lever and go around.
Hand on throttle. I always teach students to keep their hand on the throttle and not just before the throttle. You can feel sudden throttle changes indicating something is going wrong. For sure in a carbureted engine like the R22 and some R44's, if you miss the carb temperature going below 0, then you might feel the throttle being opened more and more.
Don't know if this R44 was carbureted or not otherwise carb icing could even be a cause. Still all easily to spot with a good scan (part of proper training).
Probably not really a technical issue after all. But still, feeding audible warning info into the intercom path might be a good idea in environments, where cockpit noise exceeds B747 levels.
Not knowing the real cause of the accident of course but the pilot surely doesn't have a good scanning technique missing the 80% Rrpm and that bright orange light indicating low Rrpm.
I've hade Bose and Lightspeed ANR and never failed to hear the low Rrpm horn in a Robbie or any other heli with warning sounds. You can even hear the Rrpm's once you get some flying hours.
I've hade Bose and Lightspeed ANR and never failed to hear the low Rrpm horn in a Robbie or any other heli with warning sounds. You can even hear the Rrpm's once you get some flying hours.