Tail Rotor Failure... Have you had one?
Join Date: Sep 2006
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Stuck...
FH1100,
I agree totally that it is a fairly high risk procedure, and I also agree that it is very unlikely to happen. I am, however, still in favor of training it as much as possible due to the fact that you learn so much about how to cope with difficult situations and, most importantly, you get a lot of coordination training and learn your aircraft's behavior.
Another good thing to spend a lot of time doing is quickstops. Same there, coordination.
I agree totally that it is a fairly high risk procedure, and I also agree that it is very unlikely to happen. I am, however, still in favor of training it as much as possible due to the fact that you learn so much about how to cope with difficult situations and, most importantly, you get a lot of coordination training and learn your aircraft's behavior.
Another good thing to spend a lot of time doing is quickstops. Same there, coordination.
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helispeediii
had tail rotor failure in 109a in 99 making a slowfinal approach to private site approx 60ftAGL? approx 100 yards to the spot, three greens showing, had landed there hundreds of times in different types, heard?feltbang/shudder i thought a large bird/goose?? had hit us saw nothing untoward up front did i look at the t&ps, dont know< it was inpractical to try to transition away? the aicraft started rotating at a pretty fast pace i try lowering the collective did not seem to slow down so i lower the collectrive as we were spinning round tried to cushion on landing/impact, it did not do the undercarriage much good,but i shut the fuel off shut down the engines whilst checking my pax ok he was i dont remember waiting for the shut downtime on those dear allisonsc20b, put the rotor brake on asap did not wait till it slowed?it smoked a bit did not think at the time thought the air craft was on fire time to get going but without mrb hair cut 109 on its belly front blades pretty low? my door was jammed shut told front pax to depart, eg get the f k out of here! and i followed him out, when i was out i could see it was the rotor brake smoking relielf, the aircraft was a write off, on external inspection i could see tail rotor gear box had departed taking with it most of the lower fin and a fair chunk of the upper fin,! 50/75 ft away we found tailrotor g/box with one blade attached and the root of the other blade ,this was well bedded in the ground eg high powered inpact? the part broken blade was found in a ploughed field,200ft away , aaib,/ informed,/agusta sent over two engineers from italy ,within 24 hrs to inspect,the conclusion discovered later, was metal fatigue ,even though they had a die pentrant test a month earlier,the blades were 75%of 2400to scrap life? agusta told me this had only happened once before and that was the trump machine in the usa which was a fatal ! i think they increased the inspection/xrays on the trb on early 109?, as they say if you walk away its a good one,? i was back flying 109s within aweek, and have done many hundred of hours since, needed a ciropracter to sort out my back !and my brotherinlaw is not keen on flying any more he was the pax! i had a good mate who is an instuctor,who was very helpful at the time . helispeed iii
Last edited by helispeediii; 18th Sep 2010 at 16:27.
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Just had one today, bugger. 
I was cruising a 280C at 800ft when I heard a grumbling noise getting louder and louder. I lowered the lever, carried out an auto rotation to the ground and shut down immediately because of the noise. The gears inside the trgb appear to be disintegrated and the casing was jolly hot. No damage to the aircraft and I walked away. The gearbox only had a hundred hours on it!
I was cruising a 280C at 800ft when I heard a grumbling noise getting louder and louder. I lowered the lever, carried out an auto rotation to the ground and shut down immediately because of the noise. The gears inside the trgb appear to be disintegrated and the casing was jolly hot. No damage to the aircraft and I walked away. The gearbox only had a hundred hours on it!
1988 at Aberdeen doing what was then called an "instrument base check" in an S61N and performing an ILS to runway 16. The wind was appr. 40 kts from the west causing violent turbulence particularly below 500' agl, so the training captain told ATC before commencing down the slope that he would assess how bad it was and make a late call either for a go around, or to land and taxi back to base if it was too rough.
I struggled to keep in limits and he elected to call it a day. We taxied back and shut down, followed by me going back to the briefing room while he went to the line office to sign the tech. log.
About 10 minutes later he came running wide-eyed up the stairs and told me to come to the aircraft with him. There were several engineers standing looking at the aircraft's tail which was covered in oil and one engineer was just removing the cover from the intermediate gearbox, which was still smoking.
The normally silver-coloured gearbox was blue around the top bearing area, with brown marks presumably from overheated oil. On removal and inspection 'handfuls' of metal were extracted from the gearbox, having flaked off disintegrating gear teeth. Apparently the gearbox top oil seal hadn't been installed correctly in the factory and it came out, allowing oil pumped to the top bearing to flow through it and escape.
The finding was that the gearbox was a couple of minutes from seizing, which would have happened during the climb if we had gone around from that ILS. Thank goodness that I wasn't able to fly more accurately during the turbulence. For once a poor performance was a good thing !
(In the early 1970s I was a passenger in a helicopter which suffered tail rotor control failure in the hover and crashed on its side due to the pilot's reluctance to lower the collective. But that's a different story.)
I struggled to keep in limits and he elected to call it a day. We taxied back and shut down, followed by me going back to the briefing room while he went to the line office to sign the tech. log.
About 10 minutes later he came running wide-eyed up the stairs and told me to come to the aircraft with him. There were several engineers standing looking at the aircraft's tail which was covered in oil and one engineer was just removing the cover from the intermediate gearbox, which was still smoking.
The normally silver-coloured gearbox was blue around the top bearing area, with brown marks presumably from overheated oil. On removal and inspection 'handfuls' of metal were extracted from the gearbox, having flaked off disintegrating gear teeth. Apparently the gearbox top oil seal hadn't been installed correctly in the factory and it came out, allowing oil pumped to the top bearing to flow through it and escape.
The finding was that the gearbox was a couple of minutes from seizing, which would have happened during the climb if we had gone around from that ILS. Thank goodness that I wasn't able to fly more accurately during the turbulence. For once a poor performance was a good thing !
(In the early 1970s I was a passenger in a helicopter which suffered tail rotor control failure in the hover and crashed on its side due to the pilot's reluctance to lower the collective. But that's a different story.)
Last edited by Colibri49; 15th Sep 2010 at 19:45.
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That is damn odd. Never seen a TRGB fail that early on an Enstrom. I would definitely be talking to them about a price reduction for the O/H or if it is totally trashed a price reduction on a new box.
What I have seen is the input seal fail early on a new box but presumably this was not the case in your instance as you would've noticed a loss of oil and the sight glass would've been low before your flight.
What I have seen is the input seal fail early on a new box but presumably this was not the case in your instance as you would've noticed a loss of oil and the sight glass would've been low before your flight.
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Later, back at HQ for Recurrent, an instructor brought my "event" up during ground school. I did my best, "there I was" and complained about how it did not stop spinning when I rolled it to idle. And he goes, "Idle? Why didn't you go all the way to cut-off?" He did not add the word, "dumbass" but he could have.
Last edited by FairWeatherFlyer; 16th Sep 2010 at 21:50. Reason: wrong phrasing
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In the 80s I dipped the tail of G5 bell 47 in the pacific , back to a hover I noticed I was spinning flat ( no roll from T/R thrust ) . I Figured I would just put it down in the sea than fly it away .On floats with a long swell of 2 ft seas light wind .
I rolled off the throttle and did a hovering auto from 8 -10 feet .My goal was to use all the rpm and slow the rotor before it hit the tail or sea .
The landing was firm and flat ,no blade strike . I pulled pitch and the rotor brake , happy to see I was upright .
Then I saw a tube had cracked and cut the float ,I was going to roll over in a minute . The blade went into the water like a slow butter knife as the ship rolled over . I was doing my log rolling dance with the ship inverted in the deep blue sea .
No big deal the long tubes on the floats were thinner that spec home made gear from metal yard tubing .
10 years before a bearing let go in flight in the transmission . The T/R drive would engaged and disengage every 5 -10 minutes ( bearing cage ).
It seemed like power related failure , so I lost my nerve after the 4th cycle . I made a low power shallow run on to the Glassy sea . lifting it back on deck ( without damage ) They sent out a rebuilt tranny . I changed it in a day but getting my nerve up took two days of test flights .
I rolled off the throttle and did a hovering auto from 8 -10 feet .My goal was to use all the rpm and slow the rotor before it hit the tail or sea .
The landing was firm and flat ,no blade strike . I pulled pitch and the rotor brake , happy to see I was upright .
Then I saw a tube had cracked and cut the float ,I was going to roll over in a minute . The blade went into the water like a slow butter knife as the ship rolled over . I was doing my log rolling dance with the ship inverted in the deep blue sea .
No big deal the long tubes on the floats were thinner that spec home made gear from metal yard tubing .
10 years before a bearing let go in flight in the transmission . The T/R drive would engaged and disengage every 5 -10 minutes ( bearing cage ).
It seemed like power related failure , so I lost my nerve after the 4th cycle . I made a low power shallow run on to the Glassy sea . lifting it back on deck ( without damage ) They sent out a rebuilt tranny . I changed it in a day but getting my nerve up took two days of test flights .
FairWeatherFlyer:
Heh. I can do it now!
Soave_Pilot:
Sadly, this knowledge came slightly too late for me. Hey, live and learn...
How many people practise going from idle to zilch (in a 206) with left hand only without diverting attention downwards to idle stop button? You get a chance to do that at shutdown but i doubt many people use the opportunity.
Soave_Pilot:
True... Idle won't stop the spinning.
