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-   -   R22 Engine and Rotor RPM Overspeed(past red line) - Help! (https://www.pprune.org/rotorheads/446949-r22-engine-rotor-rpm-overspeed-past-red-line-help.html)

ifresh21 26th Mar 2011 18:16

R22 Engine and Rotor RPM Overspeed(past red line) - Help!
 
Hi guys,

I had a helicopter lesson yesterday. My usual instructor was unavailable, so I flew with another who is a new instructor w/ approx. 300hrs. I had flown with him once before. I am near solo so we decided to stay at the airport - our first maneuver of the day was to be a normal closed traffic/approach/landing.

We were on final gradually descending(descending from 300agl) when I started to feel the throttle getting rolled off a little. I was thinking like whats going on- I figured it was the instructor and the throttle only went down a little so I didn't really worry. I then heard the low rpm horn and after a little thought I realized its probably a test. So as per the POH, I lowered the collective and rolled on the throttle. The collective went down by maybe 50% (pretty close to autorotative position, I believe I heard the autorotation sound a bit but I didn't go that far because of what I heard next). The throttle went on quick and hard, I was probably at full throttle. Things sounded really loud (I don't have an active headset so I can hear the engine noises, I consider that to be an important sense during flying) as the RPM increased so I looked down at the RPM gauge(engine side) and it was well above the red area/red line of rotor rpm side. Based on sound and me getting a chance to look at the gauge it felt like the RPM was up there for a period of time. I want to say less than/about 3 seconds. This all happened very quick and I was quite surprised so its hard to say exactly (crazy thing is I always fly w/ a camera and I forgot to charge it that day). The rpm went down (I guess he fixed it, happened quick) and I landed and set it down.


So that is the narrative of what happened. At the end of this post is a pic of where I remember the RPM going to during my glimpse of it (tiny red line I added).

I asked the instructor when we got on the ground hes like we don't want that to happen again. I asked him but what about right now - he said its fine cause he got it down real quick. He opened the door and checked for bearing sounds. (I can give the full narrative if you want) This was the first thing we did and total flight time was 1.6 hours.

So how bad is this, what should I do, and ultimately could someone be killed because of this(in the future due to maybe structural damage), if so - what can I do to prevent that.



http://i51.tinypic.com/21map2s.jpg(not my pic or the incident helicopter)


Thanks a lot in advance for help guys

Daysleeper 26th Mar 2011 18:26

Ground the aircraft now for maintenance before someone gets hurt or killed.

See this aaib report if you need to know why. Relevant extracts below


After takeoff, during the transition from the hover into forward flight, the engine power varied intermittently and the pilot had difficulty in controlling the helicopter, which was damaged in the subsequent landing. It transpired that the engine had exceeded its rated speed on the previous day but the maintenance organisation had not been informed and the relevant inspection did not take place.

An inspection of the engine found that the plastic gear for the left engine magneto was broken, which could account for the rough running engine and the fluctuating manifold pressure. The maintenance organisation had previous experience of this failure,which was normally associated with an engine overspeed or an inadvertent ‘dead cut’, where both magnetos are turned off whilst the engine is still running. The engineers also found evidence that the engine cooling fan had moved on its shaft, which they also considered to be consistent with an overspeed event. As a result of these findings the engine was sent to an approved Lycoming engine maintenance facility for an overspeed inspection. Clear evidence was found of an engine overspeed, with all cylinders having excessively worn valve guides and stepped valve springs.

ShyTorque 26th Mar 2011 18:48

Any exceedance of engine, transmission, or rotor limits on a helicopter needs looking at by someone suitably qualified to assess if any damage has been caused.

Not just by a 300 hour instructor who will be worried about his job.

VeeAny 26th Mar 2011 19:21

If it went there it is definitely a maintenance action.

There is no question you must report this if your instructor does not do so, it should however not be your responsibility to do so, if he does do so find another instructor.

OvertHawk 26th Mar 2011 20:00

1) Make sure it is reported.
2) Do not fly in the machine until you have verified that the maintenance organisation has been informed and have checked and released the machine.
3) Advise your fellow students not to either
4) Do not fly with this instructor again - There are questions to be asked about what he allowed to happen and there are even bigger questions to be asked about him not then reporting it
5) If you are not 110% happy with the way the school deals with this then find another one.

Have you talked this over with your regular instructor?

This is something not to be messed with - seriously!!

Good luck with the rest of your training - this was not your fault!
OH

OvertHawk 26th Mar 2011 20:11

ifresh - check your PM's
OH

Cows getting bigger 26th Mar 2011 21:04

Engineer, probably via the chief instructor's office. Red line is red line.

S76Heavy 26th Mar 2011 23:16

Yup, it's a red line.
If the manufactirer would have thought it was ok, he would not have given you those limits (red lines) to stay away from.

So, while I appreciate your insecurity (and it should not be your call as the student), you've been in test pilot territory.
Not your call to decide what needs to happen, that is up to an engineer/mechanic.

Well done for asking the question and not hiding behind that instructor. You show character and moral courage wich will serve you well.

Runway101 27th Mar 2011 00:04

Ground the ship and have maintenance look at it.

At my flight school we had overspeed issues frequently (big school). At all times the helicopters were grounded and went to maintenance for a few days. Sometimes embarrassing for the instructors, especially since it was always the same guys. It is possible that not these instructors were not good keeping the RPM in check, but maybe they were just the ones mature enough to report it.

lelebebbel 27th Mar 2011 00:37

.... and never think for one second that this was even partially your fault. It was not, and you will not be blamed for it at all.

One of the things that gets drummed into you when doing an instructor course is that the instructor has to guard the throttle and the collective. Especially when the student is manipulating either one.

The other thing that they drum into your head is that the instructor has to report overspeeds. It is a common thing to happen, especially to new-ish instructors who haven't been burned yet...
Any employer worth working for will not fire the instructor for overspeeding it (unless he did it on purpose), but they will fire him/her for trying to hide it.

Maybe you should give him a chance to own up on it and save his career, but do it NOW before someone else flies the thing.

By the way, above 110% RRPM/ERPM, there is also a high risk that the blade spindle bearings might be damaged. This can in theory lead to a catastrophic loss of control in flight.
If the RRPM where off the chart as indicated in your picture, the blades are done and need to be replaced. Robinson has a detailed list of maintenance actions in case of Rotor and Engine overspeeds, maybe someone can post it here.

ifresh21 27th Mar 2011 03:34

Thanks a ton for all the great responses. I now see that this was extremely serious and maintenance action must be taken. I will refuse to fly until maintenance is performed. Would it be too much to at some point ask to speak directly to a maintenance person responsible for the helicopter? I think I would like to hear directly from maintenance as the final step before I fly this helicopter again.

I called the school and the person who answered said that it is the instructor's responsibility to report it. I told them I want to talk to the owner/chief instructor/maintenance/etc directly with the full story. Ultimately we agreed that they will call me back.

"lelebebbel" made a good point - should I get the instructor's number directly and talk to him so that he has the opportunity to report it. It has been going through my mind that while safety is number #1, I would hate to see a new instructor go because he made a mistake(surprising a non-primary student at 250 agl on final)... Telling him what I am going to do would probably be the right thing. It is highly likely that he had no intention to report it on his own, when I called, the person I spoke to(spoke to at night the day after the day of the overspeed) happened to be one of the main instructors at the school. He said he heard nothing of an overspeed. I believe he actually flew the incident helicopter right after me and the incident instructor had contact with him (they spoke to eachother).

I will do my best to get this worked out quick - I won't be flying for about a week, but I am concerned for the others who will unknowingly be flying this R22.

So next step - get the incident instructor's number and let him know my plans and my concern for his job? Give him a day to report it. Call the school the day after and find out whats up. Monitor maintenance progression. Talk to maintenance people before I fly?

Good plan?


Thank you again to everybody. You guys are extremely helpful.

P.S. - Is there a way to view the R22 maintenance manual online at no charge?

paco 27th Mar 2011 04:54

"it is the instructor's responsibility to report it."

I would ignore that. He should have spoken up within 5 minutes of ending the flight. Talk to an engineer (they don't bite!) and if the CFI is not interested get another school after a phone call to the CAA.

phil

herman the crab 27th Mar 2011 05:54

Firstly, I think Ifresh21 is in the USA.

Its getting late and I have partaken of the falling down juice and may have missed something but did the CFI roll the throttle off? Was the governor turned off?

As said above - do you best (even though not your responsibility) to get this machine grounded until the required maintenance has been done.

The CFI's job is less important than the lives of others who might flight it.

HTC

Vertical Freedom 27th Mar 2011 07:08

r22 overspeed
 
OK glad to hear that you are concerned about the potential consequences.

1. Yes the machine needs to be inspected as all the Pilots here have correctly alluded to. Dont be shy of Engineers they are there to keep you alive & the machine making money. So build rapport with them.

2. machine is grounded, so DON'T fly till engineer clears the machine.

3. there should not be any delay in reporting this exceedance to the CFI, AME etc. Don't wait a day or 2, it should have been done same day. Even if it was the last flight of the day & everyone had gone home that Instructor should have called his CFI? If not get another Instructor.

4. Avoiding ANR? My friend that is rubbish. Apart from the fact that ANR will save your hearing so that at age 70 you'll still hear your wife nagging you. More importantly you will hear more things going on with both engine & all rotating bits. ie; few years ago I heard of a CPL doing a check ride wearing ANR, the old timer & superbly qualified senior Instructor scalding him over ANR when the CPL said, 'can you hear that strange graunching noise? The old Instructor said 'NO' everything sounds fine? But he proceeded to do an precautionary landing against advice of the Instructor only to discover that the hydraulic pump was destroying itself on a AS350 dumping hydraulic oil overboard & they were seconds away from losing all hydraulics, but saved by the refined sound inputs heard through the ANR there was no dramas.

ANR will help you greatly hear odd things that should not be there. As for not hearing the engine, that's crap, when you lose the engine the massive yaw will let you know when power is gone before the noise stops (engine failure). So get ANR & save your hearing & be able to hear all the noises, both good & bad. Also reduces fatigue hence you stay sharper longer :cool::ok:VF

Dick Sanford 27th Mar 2011 07:55

Please note that you Open the throttle before you lower the lever to recover RPM.

Runway101 27th Mar 2011 08:27


Would it be too much to at some point ask to speak directly to a maintenance person responsible for the helicopter?
Depends which school and where they do the maintenance. I walked into the maintenance department at my flight school a couple of times to speak to them. Once I was in doubt about too much play on the tail rotor bearing, and they pulled out the maintenance manual and showed me the tool to test it with, letting me know they just checked it on that particular machine and it's alright. Once I also found a crack near the oil cooler shroud during the preflight check and they came out with mirrors to see more details and grounded the machine.


Is there a way to view the R22 maintenance manual online at no charge?
No, but it can be ordered from RHC's web site using your credit card, or have a look at it when you speak to the maintenance guys they have it of course. I picked up my MM for the R22 and R44 during the safety course a few years back.

S76Heavy 27th Mar 2011 09:44

During my pilot training I was in the maintenance shed for hours every week, trying to get a more comprehensive knowledge about the machines I was flying and trying to master. So I would seriously recommend it to you as well.

Besides, it never hurts to hear the point of view from the guys and gals that keep us flying.

As for giving the CFI a fair chance to own up: I agree it is well past that point.
If, as someone has mentioned, the blade spindles have taken a beating (I don't know the R22 but know this problem from other helicopters), it has become a flying deathtrap. No room for egos, do the right thing. NOW.

Furthermore, talk to your regular instructor about this. Get a feel for the safety culture there. Because, if many exceedences go unreported in that flying school, someone will come to grief. Make sure it won't be you.

reversethrottle 27th Mar 2011 12:26

Sorry Mr Sanford - From the mouth of Frank Robinson himself...in the R22 you MUST roll on throttle and reduce collective SIMULTANEOUSLY to recover from low RRPM.

Great to see a student being proactive.

Peter-RB 27th Mar 2011 13:46

Ifresh,

The R22 must have a good engineer check all the delicate bits,

a well known operator up here in the north did the same with one of their R22s when a young and inexperienced FI allowed a stude to Auto to the ground, only trouble was said FI didnt watch over things and resultant O/Speed streched a few serious things, I was the next SFH to go up in that A/c, it was almost my last every flight anywhere, for once airborne the thing went totally u/s and would only turn right, and was shaking itself to pieces, with the help of the ATC and my huge upperbody strength I got down, determinded to pull someones nuts through their mouth , but seems every body bailed whilst I was doing a Mad Mitch in the office.

Sad to see this is still happening. all pilots should Fess up and be a man if they fark up, :=

PeterR-B

cl12pv2s 27th Mar 2011 19:24

A similar thing happend to me - But I was the instructor.

I took on a student from another school for his commercial course. The low RPM horn came on (I think in a RPM recovery drill.) Super fast panick action by my student, a strong throttle hand, a really aggressive flare and the collective dumped to the bottom...Whizzz! That RPM flew up before I could stop it. Redline - Yes. How long - Not sure, but 1-3 seconds.

So what did I do?

I landed back straight away. Told the student it was not his fault - "These things happen". Went straight to the maintenance board and grounded the aircraft. Went straight to the hanger and explained what I saw. Went straight to the boss and explained what happened.

The result...

The aircraft was grounded for 3 weeks while they sent a part away to be inspected. It came back with no damage reported. Maintenance guys, found no evidence of rotor overspeed. The boss thanked me for the honesty. The boss had a 'no-blame' culture in order to encourage this kind of honesty.

The student and I discussed the event and I flew with this student the next day in another aircraft, me, a better instructor more vigilent for such an event in the future and the student less panicky and more controlled when the horn comes on.

(From an instruction point of view, what did I learn? I learnt to treat every student I have not flown with as a new pilot.)

-------------------------------------

As an instructor and PIC the responsibilty was all mine. However, more importantly, I have a responsibility to every pilot who would fly that aircraft afterwards. If I had not reported this, and someone had flown that aircraft 3 days / weeks / months / years later, and had a fatal accident, it would be on my concience forever, whether or not their accident was attributed to my earlier overspeed or not.

To the original poster - Set your personal standards for the rest of your career right now.

There are ways to handle the situation with the instructor. You need to find a fair way. The bottom line is though is that the aircraft gets inspected.

Good luck.

cl12pv2s


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