Tail rotor chip light

[Thomas coupling]

We had another chip light the other day, no big deal......or is it??

Our EC135 crash checks state that in the event of a TRGB chip light: Land as soon as practicable .
As you are aware, this is a relaxed landing. This is also the reaction with the AS355 checks too. What do your crash checks stipulate?

What intrigues me is that these gearboxes can indicate 'chips' en-route to a break up, or can produce this caption if the box becomes too hot as a result of some mechanical problem. I have read previous crash reports where the initial indication was a TRGB chip light and then the gearbox let go:uhoh:

But the manufacturers insist on employing the land as soon as practicable option. In my humble opinion, you do this at your peril. Why would you want to fly a helicopter whose most unforgiving components are advertising some kind of distress:\

The pilot doesnt really know why that chip light has illuminated. 9/10 the problem is benign, but that last 1/10th leaves a lot to be desired.
I have changed our crash checks to state that in the event of a TRGB chip light: Land ASAP. Quickly but safely. To hell with the rest of the sortie, let's get her down, climb out and look at the mag plug/check for signs of overtemp????
My concern is that there are pilots out there who never challenge the crash checks thinking they are set in stone:mad:

Observations?

[Shawn Coyle]

Ah, the worlds of lawyers and technical stuff collides....
Probably, if you look in your checklist, you will not find a 'land immediately' emergency. You, personally might think an emergency warrants a 'land immediately' label, but the manufacturer's lawyers probably don't want to ever see those words in the flight manual / checklist, for liability reasons.
Hence the 'land as soon as posslble / practicable'. What does the flight manual define as 'land as soon as practicable'? How about 'land as soon as possible'?
What they definitely don't want is for you to do something stupid landing and then blame the company for making you do it when it wasn't needed.

[Leftpedal]

Had my first TR chip light a couple of weeks ago and sh*t myself. I was in an old R22 & it was a red light (it's amber in the newer ones - anyone know why?). I couldn't get down quick enough.

[Grainger]

Farmer's field, farmer's field, farmer's field . . . .

Ageee with TC. I'd take 'land as soon as practicable / possible' to mean the nearest safe landing spot. Somewhere between immediate forced landing and divert to the nearest airfield.

I'd far rather be sat in a farmer's field feeling a little foolish than sh*tting myself even for a few minutes whether the thing was about to let go . . .

[B Sousa]

I think just flying in an R22 is a good excuse to cleanse the system.....
Anyway Shawn is pretty right on. Manuals were written by the Manufacturer, then edited by Lawyers.
An example of the "Urgency of the Emergency" can be viewed by comparing Bell to Eurocopter. Bell books dont mind putting in "Land Immediately" in a few spots but Eurocopter seems a bit hesitant.
Based on many prior lights in my lifetime, I make up my own decision. If I find that I should land in the middle of the desert with six pax and call someone to check it out I will, versus flying for another ten minutes risking folks well being so that the company will not be to put out.
Heres one, what do you do when over the ocean and get a chip light...Been there also.... It changes the whole ball game. I know in Main Transmission lights I am heading for the water and when I think other indicators tell me its serious, I get ready to inflate the rubber ducky........
Bottom Line Pilots have to think about things, use the gray matter when making decisions. Company may not like it, but they can fire you...easier than burying you.

[Thomas coupling]

Definition of:
Land immediately.
The urgency of the landing is paramount. Primary consideration is to assure survival of the occupants. Landing in water/trees or any unsafe area should be considered only as a last resort.

Land as soon as possible.
Land without delay at the nearest adequate site at which a safe approach to land can be made.

Land as soon as practicable.
The landing site and duration of the flight are at the discretion of the commander. Flight beyond the nearest aviation location is not advised.

Shawn: I don't think 'immediate' comes into this malfunction from the outset. What confuses me is that there is a marked difference between the other two remaining options. I firmly believe the manufacturers have looked at this quite conscientiously, but I can't for the life of me understand why they have " downgraded the response. Many 'professional' pilots will always see this as a dumbing down of the possible outcome of such a malfunction and not get too worried over it.

There are extenuating circumstances as described by B Sousa, but I was speaking of the overland scenario in essence where there were very few variables to affect the pilots judgement.

Why dont the manufacturers err on the safe side and recommend land as soon as possible. This is a safe and controlled maouevre to land, no big deal (in the day anyway!!).???

Atleast in the S61, one had a caption for 'hot' and one for 'chip'!!

[NickLappos]

This always comes up, and was actually debated by the FAA and some of us as reason to get rid of chip lights, because there is nothing more compelling than that little light is there? The light means that some debris is on the plug, that is all it means. Maybe there is a slight increase in the probability of a problem, maybe not. That is not a reason to do anything impetiously. Over reaction could make for more safety problems than the somewhat increased probability of a gearbox problem that the chip light tries to tell you. I know of at least two very healthy helicoopters that were destroyed by pilots who decided that the light was license to do something extraordinary. Of course, any confirming separate indication (temp, vibration, etc) and the whole decision making exercise changes!

Let's review what those pesky RFM words mean:

Land Immediately: yep, now. If you can't get to a nice place in a minute, just ditch. Shorthand - land anywhere.

As Soon as Possible: Nearest safe place (golf course? Ball field? Just land the machine but don't ruin it). Shorthand - land on a golf course

As soon as practicable (or practicle): Nearest regular landing site. Don't fly past one to go to a more convenient one. Shorthand - land at a heliport/airport.

If you decide to make the words mean something else (kick them up a notch or two) on your checklist, you are now in the realm of procedure inventor, and might find an embarassing number of freinds who ask lots of questions if your new procedure differs with the one the FAA/JAA approved.

Shawn, Sikorsky still uses "Immediately" in their RFM's. I guess we need a few more lawyers.

[jeppsbore]

Slightly off topic but I have worked on many types of helicopters and fixed wing for more years than I care to remember. Having dealt with quite a few chip lights in the past I have thankfully never been involved with a total transmission failure, engines on the other hand I,ve found can let go with very little warning i.e. moments after the chip light illuminates. So figure this out, several turbine (particularly PT6) fixed wing A/C I have worked on have chip detectors that aren't wired to a convenient lamp on the panel, the only inspection required is to check them with a multi meter for continuity every 100 hours. Therefore you could theoretically fly for 99.9 hours with a chip light and not know it! A prop reduction gearbox failure on a single engine A/C at 30000 ft can be just as messy as a tail rotor gearbox failure at 500 ft, so go figure why for the price of a length of wire and another lamp on the panel the pilots are left in the dark...

JB:confused:

[SASless]

Does Thomas fly BK's?

Commonsense alone should tell one to land at a safe spot and figger it out from there....would you not feel the mug if you overflew a nice pub or tavern and then had a gearbox failure? Why are we getting hung up on print on paper here? Do the safe thing....the flight can wait.

[Bomber ARIS]

Probably, if you look in your checklist, you will not find a 'land immediately' emergency. You, personally might think an emergency warrants a 'land immediately' label, but the manufacturer's lawyers probably don't want to ever see those words in the flight manual / checklist, for liability reasons.

Shawn, perhaps a little too cynical. All the Bells I've flown (apart from, perhaps, the 47), and every Eurocopter product I'm type rated in, contain the good old "LAND IMMEDIATELY". Surely not even American lawyers would want helicopters to remain in flight if a "Land Immediately" would have been the manufacturers original advice.

[Helinut]

Surely this is what we as pilots get paid for: making the real decisions in the real world.

Let me give you another recent example which works the other way (maybe): AS 355 doors caption. For those who do not know the Squiggle, a bit of background. There are 3 baggage doors that are behind the cabin and not visible from it. The consequences of these doors coming open in flight could be serious - they could even come off and hit a rotor blade or two, or even a third party walking his dog. However, the history of these doors and the associated captions (in my experience) is that they are for ever causing false indications. Some individual aircraft seem particularly prone.

No one , not the Belgrano or the manufacturer seems to do much about what is IMHO a poor engineering system; it is just accepted as "one of those things". This is not the only example of that attitude in this game of ours, but that is another story.

Anyway, there I was fat, dumb and happy operating fairly low-level over a big built-up area at night when the DOORS light comes on. I happen to be operating over a park, but it is cluttered with obstacles including my least favourite : wires. The AFM more or less says, and our FRCs DO say "land as soon as possible". In the interpretation of some, this says land in the park. However, I decided to land at a closed but known helipad site a few miles away, which was free of obstacles, following a slow speed transit to reduce the chances of any door
a)opening; and
b) coming off

No problem: well-placed "kick" to the door and "all is well".

I think I was managing the risk sensibly. (When I vary from procedures defined by manufacturer or operator I always try to rehearse my testimony to the "board of inquiry" as to why I did, as part of my decision-making).

If faced with TC's issue, I would land as soon as possible (rather than what the AFM says), so long as the risks of landing were not great. I also agree with TC that it does not make sense to me that TR chip is land as soon as practicable.

[You should note that the AS355 AFM says "continue the flight - avoid prolonged hover flights" - not EVEN a "land as soon as practicable" - this seems MAD to me. The cost of land as soon as practicable is negligible (usually)]

But, in the end it all depends on the situation, which is why they have pilots.............

Reviewing what others have said, I think that B Sousa may have it about right - make your own decision, in the light of the circumstances .

[4ero]

I've always figured if the chip lights comes on land at the nearest convenient and safe place.

If the light comes on and is accompanied by unusual vibration/noise/general sense of doom put her down straight away.

[Gomer Pylot]

One thing to consider: with the throttles on the ceiling, it can be somewhat of a problem if you're landing to a confined area and the tail rotor does decide to crap in the bed. You may be better off flying to a place where you can make a running landing, because if it happens in cruise flight it's not immediately catastrophic, but if it happens at about 10 feet in the middle of wires, trees, and other assorted obstacles it may well be. You're getting paid for your judgement, so you had best use it, and use it wisely, considering all the pertinent factors.

[Arm out the window]

Also worth thinking about what happens once you do land in the paddock. This is one of the areas where pilot maintenance might be in order, given appropriate familiarisation beforehand.
The chip lights I've had have generally been reacted to as follows:
1. Land in nearest suitable area (eg the golf course or paddock).
2. Maintainers undo the plug and inspect for chips.
3. Flush the debris from the plug into a spew bag or other suitable container to keep for later inspection.
4. Replenish the oil that was lost when you were inspecting.
5. 20 minute ground run.
6. If the light doesn't come back on, fly back to base for further inspection.

Most times you're on your way quickly anyway, so it doesn't seem such a big deal to land and have a look if you've been instructed in what to look for, not a bad option if you're halfway across the Nullarbor or whatever. Depending where you fly, different kinds of pilot maintenance are allowed; chip plugs don't seem to be mentioned specifically in our regulations for approved pilot maintenance items, but they do say pilots can change oil filters, replenish oil, change spark plugs and so on, so it's not too much of a leap of imagination to think that removing, inspecting and replacing a chip plug would be beyond the humble driver, particularly if you can get in touch with an engineer for some guidance.

[Thomas coupling]

Nick, I would like to take issue with you over this, if possible:

First off: nothing in the Flight manual is compulsory or mandatory except statements with 'shall' or 'must' and the section on 'limitations'. As you know.
Usually (though not in every case), there is a precursor to the crash checklists stating that these recommendations can be over ruled by the a/c commander, in the interests of safety. That is to say, do your 'professional' bit and if it differs significantly from the FLM, then be prepared to back them up!

However, and this is where we differ, I have experienced a TRGB with a 'hot' caption which genuinely told me the truth and the gearbox was leaking. I have also read 2 crash reports on AS355's where there was a chip light from the TRGB and the pilot continued flying - the gearbox packed up!!
Of course, 90 something percent are simply 'swarf', but does one really want to take that chance? Therefore, WHY does the Twin Star (Squirrel) state: continue with flight???????
Why does the EC135 state: land in your own time at the nearest airfield or similar (land as soon as practicable). WHO ARE THEY KIDDING????
In my experience I have observed that if you present most pilots with a low priority option, you are sending the message that the malfunction is not that serious. A TRGB chip scenario should (with these 2 example a/c) be afforded a much higher priority rating, I'm afraid.

This is the message I'm trying to get across, SASless; The hang up, for this malfunction unfortunately, is "on pieces of paper", in that it is suggesting to pilots, that a TRGB chip is no big deal. IT IS:oh: Commonsense shouldn't need to kick in after the light illuminates, such that you put down and check it out. It should kick in when they print the bloody manual:sad:

[Shawn Coyle]

or how about make more robust, or better designed and manufactured tail rotor gearboxes?

[212man]

I think the term "crash checks" is a bit of a melodramatic start to dealing with an abnormal event; that alone is bound to get the pulse up!

[Buitenzorg]

Helinut, you must be flying a different type AS355 than I do. My RFM states, in the case of the DOORS warning light:

1. Reduce speed below 120 kts.
2. Visually check doors.
3. Land IF possible (my emphasis).
4. If landing not possible, continue flight at reduced speed. Make shallow descent with low sink rate.

NOWHERE does it say to land as soon as possible, with the implied acceptance of greater risk during landing that at a prepared aviation site. In other words, you carried out precisely the procedure recommended by Eurocopter.

BTW, you are dead right that the luggage doors on the AS350/355 are "engineered to fail".

I agree that the first line in almost any emergency procedure should be "use your brain". As one TRE on the 212 told me, one of his favorites is to have one engine shut down for low oil pressure or the like. Then a fire in the other engine is simulated. The number of students who will immediately shut down their only running engine regardless of terrain or other factors, simply "because it is the procedure" is over 50% he tells me.

I guess that Eurocopter (or Aerospatiale as they were then) were trying to tell us "Don't risk smashing up the aircraft because of this light. Set it down when you're sure it's safe to do so."

BTW, aren't crash checks done by the accident investigation team? You know: after the crash?;)

[CyclicRick]

If I had a TRGB Chip it's "land as soon as possible" ie get it down safely, same with anything with the MRGB. I won't mess with that kind of caption.
I've had 2-3 eingine chip lights in 206's which were practically nothing upon inspection, and one plug in a 350 which looked like Bob Marley when taken out. I had 5 pax on board and popped it straight into the next glider field 2 minutes away. I was told afterwards that the bearing would have failed within minutes! Good decision that one!
The "Doors" caption can be a pain in the 350, most of the time the cause is that the corner of the door is usually bent or cracked where the switch is which you can usually see on pre-flight, so I always lock them just in case.

[Ascend Charlie]

Pilot Maintenance:

I have multiple entries for maintenance items in my maintenance authority, but nowhere is there an entry for "Inspect chip detector."

Some years ago I had an engine chip light in an Agusta 109, miles from anywhere. I landed, waited for the engine to cool enough to reach around it for the plug, removed the tiny chip, and spoke to the engineer by phone. (Luckily in range of a base station). Ground ran it, and came home.

CASA got wind of it and threatened action, because in their opinion, I could not assess what was an acceptable chip and what wasn't.

Well, if a chip has a part number stamped on it and an unserviceability tag attached, it's a bad one.

[mickjoebill]

If unsure that the chip light warning is spurrious check that the paint on the gearbox hasn't peeled due to heat...

A usefull additional glance isn't a flakey idea during the preflight?

Mickjoebill

[TheShadow]

No-one ever told me not to hover downwind in a Iroquois. So I figured that, if I could achieve a better up-front hover reference for winching and/or external loads hook-up, why NOT?

Well one bad day I found out why not. I had two persons in the strop on a high hover winch and the first hanger bearing aft of the jet efflux let go. It just overheated, lubrication broke down nd it popped right out and the T/R driveshaft cover got flung off and the feedback through the T/R pedals went to extreme. It took me about 10 to 15 seconds to sink the hoist-buddies back onto the ground, chop cable and subside to the right into a convenient clearing before the whole shebang let go. Luckily all the damage I got was a whole bunch of later hindsighting "Didn't you know that.......etc, etc"

Maybe they should have a chip detector or overheat light for that first hanger bearing. About 15 seconds is all you've got once they depart their housing. My recommendation is to hover crosswind or into wind, notwithstanding the difficulty with hover references. Learn to hover alongside a reference (but I was never taught that). Think about where you're going to dump it pronto (when and if the pedals start dancing).

Tail rotordrive-shaft failures in the v high hover above secondary jungle tops are potentially a diurnal ruination.

TS

[NickLappos]

TheShadow,

Why not ask for a real helicopter, instead of one with a fatal flaw and a warning light?
It is pretty vclose to the time when we should ask for machines that are actually doing what we ask, and having us do what they want.

Imagine allowing your daughter to drive a car where a warning light for the wheel bearing comes on, and if she doesn't pull over, the wheel will explode and roll the car over!

[overpitched]

Arm out the window


Once you have landed the aircraft with a chip light on you would have to put it on the M.R. ...simple. Once it's on the M.R. you can't fly the aircraft...simple.

[albatross]

From reading this thread I get the impression that:
1: there are a lot of tail rotor gear box failures because everyone seems to think that if the chip light comes on the damn thing is about to explode.
2: Everybody is flying in the circuit or at most a 20 miinute drive from the hangar.

So anyhoo it is 1 1/2 hours to sunset - you are 1 hour from home or anyplace else for that matter- it is -35C with a 30 knot wind. The tr chip light comes on.
What are you going to do?

[Hilife]

For what its worth, when I think gearbox chip light I think back to the 1982 US Army CH-47C crash in Mannheim, Germany.

The crew observed a flickering transmission chip light at 8,000 odd feet and took steps to land immediately, but tragically at about 500 feet the fwd transmission failed, the heads de-phased and the outcome for the 46 crew and parachutists on board was inevitable. I might point out that it was not old technology that caused this accident but a change in gearbox overhaul cleaning procedures.

Jeppsbore - Regarding the very reliable PT6A engine, most are fitted to 2-engine aircraft and therefore the failure of one would still leave you one to get you to an airfield, maybe single engine installations all have chip lights? Also it is likely that the break-up of the gears/bearings and bushes will clog up the prop governor inlet screen resulting in a fluctuating prop and thereby alerting you to the fact that something is up.

Thankfully transmission failures per flying hour are pretty rare but they do happen.

For me it does not matter how many false alarms you get, you just never know. I favour backing off on the power and taking it steady to the nearest and safest piece of ‘terra ferma/rig/icepack/boat deck’ you can find.

Don’t think profit and bollocking’s, think making it to retirement.

[delta3]

Albatross

Have

- water, preferably some wine
- some food (maybe there some fishing gear will do)
- a light
- a sleeping back, preferably a tent, but the heli-cover also might do
- a phone, preferably iridium or a very cool wife

d3

[loachboy]

Left Pedal,
I believe the reason for the change from Red to Orange lights in Robbies. Was becasue, the 'Low Fuel' light used to be RED but at soon as it would come on in flight pilots were auto'ing to the ground risking the machine and it's occupants, instead of landing safely as soon as possible.

Spank me if I'm wrong !

Regards

Loachboy

[offshoreigor]

Hi TC,

High and Fast to the first suitable! There's always Hartlans Point!

Cheers

:eek: OffshoreIgor :eek:

[Thomas coupling]

Hi Offshore - jeez you get around, where are you misbehaving now?

A reminder of the good old days:ooh:




all in a days work! (http://www.verticalreference.com/Videos/LossTailrotor_56K.wmv)

[C of G]

I happened to overhear a conversation last night concerning the right to land in the event of an illuminated chip light from a pilot who was previously flying in the Washington D.C. area. She was of the opinion that because the RFM stated "Land as soon as practicable" she would be violated in making a precautionary landing. She said she had such an event and had to fly for quite a bit to leave the area and even had a passenger ask to land the helicopter, if I heard correctly. I am feeling the tendency to disagree, but I never flew in that area and I'm not sure how restrictive it is, but I would assume if you have the clearance to fly in the area you would be able to deal with an in flight emergency as well. I uncharacteristically kept my mouth closed last night, but would be interested in anyone's input. Would you be subject to the FAA's wrath for landing in this situation? Thanks.