R-22 massive overspeed

[DRAGON-21]

The school I go to had a massive overspeed on an R-22 and I was wondering if anyone has any ideas...

 

The governor was maintaining RPM in the green area after recovering form an auto, the heli was in a hover a few seconds after the auto, and BAM!!!!, the engine just started screaming. The instructor rolled off the throllte but it was too late...

 

What would cause the governer to go full throttle like this?

 

I have heard the magneto could be the issues but more specific, like, what in the magneto?

 

Can a cell phone confuse the electronics?

 

Thanks

[Jaybee]

The magneto provides a "tachometer" feed.

 

Anyhow, "massive" is defined as what ? depending on the actually % hit, will require the blades to be removed and inspect the bearings and possibly even an engine teardown.

[pilot#476398]

Yeah, happened to me once. Just sitting in a hover and then BAM rpm jumps up! They called it a "governor surge",...never did find out why it happened?

 

...and I never saw that 22 again.

[Flying Pig]

"massive" and "overspeed" are two words I don't normally think of when it comes to an R22. I guess the terms are relative So what I mean to say is, I have nothing worthwhile to offer to this discussion.

[Jaybee]

Ooops, forgot to say - magneto provides tach feed AND possibly a bad condenser on the magneto points is giving a dirty signal, or tach wire feed is routed too close to spark plug wires and a long list of other possibilities but those would be two most likely.

[Nearly Retired]

I have no experience in Robinson products, but I have a lot of experience with human products. And in this case...call me skeptical.

 

"Massive overspeed?" So many questions! Were both pilots asleep? Does the governor work through the throttle linkage? Did nobody have their hand on it to stop the spool-up? I mean, I know things happen fast sometimes, but just how fast can a little 4-cylinder Lycoming accelerate an R-22 rotor system before an overspeed becomes "massive?" Did the nose yaw strongly to the right, and did the ship balloon upward? Can you get the same effect by snapping the throttle full-open at a hover?

 

A turbine engine can spool up or down independant of "throttle" position, but a recip cannot spool up on its own. Has this "sudden spool-up" of R-22 engines been documented? Or are the events all anecdotal, as in, "Gee, it did it once but we cannot get it to do it again."

 

Until we have more information about this anomaly, it's impossible to say what happened...or when it happened...or what caused it.

[pilot#476398]

I have no experience in Robinson products, but I have a lot of experience with human products. And in this case...call me skeptical.

 

"Massive overspeed?" So many questions! Were both pilots asleep? Does the governor work through the throttle linkage? Did nobody have their hand on it to stop the spool-up? I mean, I know things happen fast sometimes, but just how fast can a little 4-cylinder Lycoming accelerate an R-22 rotor system before an overspeed becomes "massive?" Did the nose yaw strongly to the right, and did the ship balloon upward? Can you get the same effect by snapping the throttle full-open at a hover?

 

A turbine engine can spool up or down independant of "throttle" position, but a recip cannot spool up on its own. Has this "sudden spool-up" of R-22 engines been documented? Or are the events all anecdotal, as in, "Gee, it did it once but we cannot get it to do it again."

 

Until we have more information about this anomaly, it's impossible to say what happened...or when it happened...or what caused it.

 

Well when it happened to me;

 

I was in a hover and had just made my radio call to the tower, when I got a sudden yaw, followed by the ship going up (it was windy so I didn't think that much of it until I heard the increase in rpm). When I looked down the needles were split seemingly as high as they could go! Keep in mind, this all happened in about a second or two. I did not feel the throttle suddenly roll up (although Robbie throttles have more friction on them than say a 300, or Ensrtom, so maybe that's why I didn't feel it rolling up?,...I really can't say?). I then chopped the throttle and set it down.

 

Later when the mechanic took it up he got the same type of governor surge. A couple of months later I inquired about it, but they still hadn't found the cause.

[Mikemv]

What did the PIC write up in the aircraft log for power on overspeed as to how far it oversped and for how long?

Edited January 14, 2014 by Mikemv

[iChris]

The school I go to had a massive overspeed on an R-22 and I was wondering if anyone has any ideas...

 

The governor was maintaining RPM in the green area after recovering form an auto, the heli was in a hover a few seconds after the auto, and BAM!!!!, the engine just started screaming. The instructor rolled off the throllte but it was too late...

 

What would cause the governer to go full throttle like this?

 

I have heard the magneto could be the issues but more specific, like, what in the magneto?

 

Can a cell phone confuse the electronics?

 

Thanks

 

You’re our inside man on this. You have all the inside information. What’s going on at that flight school? Have you found out anything new?

 

On the surface it appears to be that old story, pilot error, nothing wrong with the aircraft. Training over-speeds during Power recovery autos are legendary in the R22. Please let us know what really happened and the cause.

 

Also, you didn’t say what type of over-speed. Was it just rotor RPMs between 110-116 or was it above 116? Maybe they even over-sped the engine’s 2,700 RPM rating.

 

Jaybee is correct in his post about the magneto issue and the R22 maintenance manual substantiates that as a majority of governor problems.

 

“The majority of governor problems are caused by the engine's right (helicopter left side) magneto tachometer contact assembly points being out of adjustment or faulty. Erratic operation is usually indicative of tachometer contact assembly problems or wiring damage. Crushing, pinching, or abrasion, all of which can result in grounding of one or both center wire conductors to the shielding or to structure, may evidence wiring damage. Tachometer contact assembly problems may be caused by contamination, oxidation, or loose contacts.”

 

However, those problems are more progressive than catastrophic, percentage wise. If no ones reported any surging or erratic governor issues prior to this, the scales tip toward the instructor/student. The instructor has to guard the throttle and the collective. When you look at were and when this happened, based on the relative ease of over-speeding the R22, you just have to take a second look inside the cockpit.

 

“The governor system is designed to assist the pilot in controlling the RPM in the normal operating range. It may not prevent over- or under-speed conditions generated by aggressive flight maneuvers. Within the active range there is a 3%-wide deadband from 102.5% - 105.5% where the governor will not take action provided the rpm is steady.” - R22 Maintenance Manual 8.230

Edited January 14, 2014 by iChris

[Trans Lift]

Yeah was it an engine overspeed (sounds like it from what you're saying) or a rotor one?

Edited January 14, 2014 by Trans Lift

[DRAGON-21]

Thanks for the information guys. I don't have much to add, I wasn't there, but I do know that it was both the engine and rotor and it went real high. Above the marks on the gauge, maybe all the way up. They were basically hovering when it happened.

[WolftalonID]

Like many have stated, training over speeds are so common from death griped students and over relaxed cfi's to faulty mechanics of parts on the ship. This is a tricky diagnostic to perform.

 

One can easily define by looking at the ships components how bad the damage is and then go about fixing it. The mechanic can not usually determine how much of the damage was a result of incompetent pilot actions.

 

Some CFI's are so paranoid of admitting a mistake for their job or reputation, ship part failure or the " i have no idea" ghost is the culprit.

 

Honestly, most students really wont know they were the cause of what went wrong, but the CFI should have a better grasp of the moment. When the CFI is left wondering, it leans more toward the ship as the issue, but not always.

 

I have not done a massive overspeed yet, I have always been careful to pay attention to not over grip and allow the ship to work its magic on that Governor. I also remember my first few autos....or maybe sorta remember them... My instructor rather flew them while I bug eyed out the window lol.

 

Hopefully they fix her up and get her flying again soon. Good luck finding your mystery cause.

[Mikemv]

What do the Robinson and Lycoming MMs say for maximum power on overspeed inspection/replacement of parts?

Edited January 14, 2014 by Mikemv

[aeroscout]

If I ever get any 22 time, I will bolo for overspeeds.

Flying Pig, are you around to bolo ?

[Spike]

I’ve got your bolo right here…..

 

For an over-speed to occur for unknown reasons is unlikely. That is, if an over-speed were to occur without cause, based on normal operating procedures, would necessitate a need for further investigation by the manufacturer or the feds. Furthermore, it would be ridiculous to assume, “it just happened” or “it’s happened before”. This kind of statement borderlines on ignorance and/or negligence……

 

Get real, any helicopter that would do anything suspected as “un-commanded” would be grounded in a nanosecond. Especially, a Robinson product…….

Edited January 14, 2014 by Spike

[lelebebbel]

iChris has basically laid it all out as far as the probably/possible cause for these events goes...

 

FYI, here are the overspeed maintenance procedures, straight from the R22 Maintenance Manual 2.540 and following:

 

http://www.robinsonheli.com/manuals/r22_mm/r22_mm_2.pdf

 

 

 

... and Lycoming SB 369:

 

http://www.lycoming.com/Portals/0/techpublications/servicebulletins/SB%20369C%20(04-18-2012)/Engine%20Inspection%20after%20Overspeed.pdf

 

 

In short, engine overhaul.

Edited January 14, 2014 by lelebebbel

[Mikemv]

So, the reported (here) over speeds were power on requiring addressing both rotor system and engine as per RR MM 2.540B & C.

 

Did this helicopter fly again the day of the over speeds?

 

Is it still flying?

 

Blades and spindles going to Robinson?

 

Tear down/inspection of engine as per Lyc. SB 369?

 

Follow Industry Standard Practices.

 

This is definitely a "refuse to fly it" situation!!!!!!!!!!!!!!!!!!!!!!!

 

Mike

Edited January 14, 2014 by Mikemv

[Flying Pig]

If I ever get any 22 time, I will bolo for overspeeds.

Flying Pig, are you around to bolo ?

I don't know much about the mighty Robbie other than somewhere in my logbook there is hidden 10.1hrs total time in type that I never speak about at dinner parties. It only comes up with my therapist. It was a dark time in my life. Im not proud of it.

Edited January 14, 2014 by Flying Pig

[500E]

Sat in one once, got out befor it started.

If it was that bad you want to keep clear of it, find out what remedial action was taken, if none change flying school

[pilot#476398]

I don't know much about the mighty Robbie other than somewhere in my logbook there is hidden 10.1hrs total time in type that I never speak about at dinner parties. It only comes up with my therapist. It was a dark time in my life. Im not proud of it.

 

That's exactly how I feel about the 10.1 hours in a Jet Ranger I paid for long ago!

[Dragbrace]

Don't mean to offend anyone here by being old school but I can't help but notice that we have raised a generation of new pilots that don't fully understand the concept of power management. Back in the throttle twisting days we were taught to recognize situations that required extreme power settings and how to avoid them.

 

I have ridden with a number of new pilots that pay little attention to manifold pressure gauges or torque meters until the horns and lights come on. Not to bad mouth the instructor, but he should have caught the situation, intervened, and made a productive lesson of how to avoid that situation.

 

To me this is one reason our industry is in the sad shape that it is in. We teach our new pilots to fly the aircraft but spend precious little time teaching situation awareness, explaining basic principles or how to avoid potential bad situations. It is no wonder that experience levels are so high for entry level employment.

[Nearly Retired]

 

Well when it happened to me;

 

I was in a hover and had just made my radio call to the tower, when I got a sudden yaw, followed by the ship going up (it was windy so I didn't think that much of it until I heard the increase in rpm). When I looked down the needles were split seemingly as high as they could go! Keep in mind, this all happened in about a second or two. I did not feel the throttle suddenly roll up (although Robbie throttles have more friction on them than say a 300, or Ensrtom, so maybe that's why I didn't feel it rolling up?,...I really can't say?). I then chopped the throttle and set it down.

 

Later when the mechanic took it up he got the same type of governor surge. A couple of months later I inquired about it, but they still hadn't found the cause.

 

Okay, no disrespect intended, but your answer raises even more questions than it answers.

1) When you say the tach needles were split “as high as they can go” do you mean that the engine needle went above the rotor needle? Or do you mean they were not showing the goofy “crossed swords” indication that you Robbie pilots normally see? Because the former is impossible unless the clutch failed.

2) Can the governor of an R-22 impart such a force on the throttle linkage that it can overpower the pilot holding onto the throttle? I once flew an R-22 and noticed that the throttle was covered in some sort of squishy foam rubber crap. Are they still? It may be comfy but I felt then and still feel now that it's a horrible idea in an aircraft that requires constant and delicate manipulation of said control. I ask this because during that one-and-only time I ever flew an R-22, the pilot would only allow us to do hovering autos from a very low height - like three feet MAX. And even at that they were a very fast, "chop-and-immediately-cushion" affair. I cannot imagine doing one from higher than about three feet without spreading the skids unless you had extraordinary technique and luck. If your RPM surge caused you to balloon up in altitude, how did you handle the resulting hovering auto from that height?

I've scoured the web (via Google) for information on R-22 "high-side" governor failures. Evidently they are very, very rare. However, I do not doubt that electrical/mechanical components can fail. I do not doubt that there are intermittent problems that we pilots experience that are frustrating for mechanics to troubleshoot. I do not doubt that things happen quickly in a helicopter - sometimes more quickly than we can process and react.

I do doubt that Robinson would ever certify and install a piece of equipment that could result in a situation with a damaging outcome. In other words, I doubt that the governor can overpower a pilot's hand. And if it can, I'd never fly an R-22 with the governor on. I also tend to doubt that the governor can "snap" the throttle open so quickly that a pilot could not catch it (although I stand to be corrected on that one). And even if this happened I doubt that the governor would just spontaneously release its hold at "full-open" and go back to normal operations.

So there's obviously more to these anecdotal stories than we're hearing. But I'm interested in hearing the "more." As someone who flies a piston engine helicopter with no governor and a very weak correlator to boot, I'm always curious about new technology and how it works in the long run.

[pilot#476398]

 

Okay, no disrespect intended, but your answer raises even more questions than it answers.

 

1) When you say the tach needles were split “as high as they can go” do you mean that the engine needle went above the rotor needle? Or do you mean they were not showing the goofy “crossed swords” indication that you Robbie pilots normally see? Because the former is impossible unless the clutch failed.

 

2) Can the governor of an R-22 impart such a force on the throttle linkage that it can overpower the pilot holding onto the throttle? I once flew an R-22 and noticed that the throttle was covered in some sort of squishy foam rubber crap. Are they still? It may be comfy but I felt then and still feel now that it's a horrible idea in an aircraft that requires constant and delicate manipulation of said control. I ask this because during that one-and-only time I ever flew an R-22, the pilot would only allow us to do hovering autos from a very low height - like three feet MAX. And even at that they were a very fast, "chop-and-immediately-cushion" affair. I cannot imagine doing one from higher than about three feet without spreading the skids unless you had extraordinary technique and luck. If your RPM surge caused you to balloon up in altitude, how did you handle the resulting hovering auto from that height?

 

I've scoured the web (via Google) for information on R-22 "high-side" governor failures. Evidently they are very, very rare. However, I do not doubt that electrical/mechanical components can fail. I do not doubt that there are intermittent problems that we pilots experience that are frustrating for mechanics to troubleshoot. I do not doubt that things happen quickly in a helicopter - sometimes more quickly than we can process and react.

 

I do doubt that Robinson would ever certify and install a piece of equipment that could result in a situation with a damaging outcome. In other words, I doubt that the governor can overpower a pilot's hand. And if it can, I'd never fly an R-22 with the governor on. I also tend to doubt that the governor can "snap" the throttle open so quickly that a pilot could not catch it (although I stand to be corrected on that one). And even if this happened I doubt that the governor would just spontaneously release its hold at "full-open" and go back to normal operations.

 

So there's obviously more to these anecdotal stories than we're hearing. But I'm interested in hearing the "more." As someone who flies a piston engine helicopter with no governor and a very weak correlator to boot, I'm always curious about new technology and how it works in the long run.

 

Again keep in mind we're talking about something that happened in just a couple of seconds. It was over before I had time to finish saying, "What the Fu...!"

 

In retrospect (this did happen a couple of years ago) my hand may have been pulling up the carb heat when it started?...don't remember everything exactly? So that would answer any governor overpowering hand idea? Perhaps I could blame this on the "card-heat assist" which lowers the the heat (often into the yellow) when you pull into a hover, causing the pilot to re-set it once in a hover? In other words if this had been a Beta (no carb-heat assist) my hand definitely would have been on the throttle to catch the surge before the rpm went too high?

 

The ship didn't balloon up, it just started to rise, so when I chopped it I wasn't really that high. (yeah, they don't like us hovering very high in these things to begin with, if you're at 5 feet an instructor will generally tell you to go lower!) So a normal hover is around 2 feet.

 

As for the needles, the only thing I can be 100% sure of is that they both looked like they went way up and the swords were no longer crossed. If I had more than a couple of seconds to stare at the gage perhaps I could be more precise? When I told the owner he said it just may have looked that way because of my perspective (looking down at the gage, since its below eye level) and that they possibly didn't go as high as I thought? I think we settled on 130% for the overspeed estimation,...if I remember correctly?

 

The throttle is still covered with that cushy foam crap, and as someone who has flown helicopters without a governor and/or correlator, yes the robbie throttle does suck in comparison when the governor is off!

 

I wish I had more to add, but it just happened way too quick. However since the governor did surge again when the mechanic took it up, something must have happened? Unfortunately I never found out what!

Edited January 14, 2014 by pilot#476398

[Nearly Retired]

All good info, pilot, thank you!

 

What this demonstrates is that bad sh*t happens FAST in a helicopter. You might think that two seconds is an awful lot of time...but it's not. And...Murphy's Law being what it is, that sh*t will happen when you have your hands off the controls (tuning a radio or some such) or are otherwise concentrating on something else.

 

The takeaway for me is to understand that such governor failure modes are possible, and to be on the lookout for them.

[Jaybee]

Don't mean to offend anyone here by being old school but I can't help but notice that we have raised a generation of new pilots that don't fully understand the concept of power management. Back in the throttle twisting days we were taught to recognize situations that required extreme power settings and how to avoid them.

 

I have ridden with a number of new pilots that pay little attention to manifold pressure gauges or torque meters until the horns and lights come on. Not to bad mouth the instructor, but he should have caught the situation, intervened, and made a productive lesson of how to avoid that situation.

 

To me this is one reason our industry is in the sad shape that it is in. We teach our new pilots to fly the aircraft but spend precious little time teaching situation awareness, explaining basic principles or how to avoid potential bad situations. It is no wonder that experience levels are so high for entry level employment.

 

Couldn't agree more.