EC120

[toptobottom]

John - looks as though it happened on an airfield... Strange that only one blade appears to have any damage And surely that hole in the canopy isn't blade damage?!

[toptobottom]

Here we go (thought the strike was too close to the root of the tail)...

Click here.

"Apparently the crew were practising auto rotations above the threshold of Runway 34 at Cape Town International Airport when, during one such practise, the tail hit the ground and broke off."

[John R81]

Thanks TTB. Had to be one heck of an impact on the tail to do that. I thought the order of failure was stinger bend, fenestron, tail boom.

I was less than 100m (in a 120) from a 120 who flared late on practice auto, tail hit the ground but got away with a bent stinger. That impact looked "large" to me, though he did have 65kts fwd speed and it was onto grass.

Gotta cause severe hurt in the wallet area, that one!

[toptobottom]

A bruised ego and a dented wallet - at least they walked away...

[generalspecific]

VEMD - A Technical Question

At what point does the VEMD start monitoring during the start sequence. Is it possible for the blades to turn and a light off to occur followed by a shut down and for that cycle not to be recorded on the flight report?

[puntosaurus]

I wouldn't swear to it, but I think what you describe is possible.

I've only been in the aircraft for one aborted start (because the T4 was getting a bit lively), and from memory there was no increment to the flight number.

However I bet I can guess your next question, and I'd lay odds that if there was an exceedence in that period then the flight would indeed be logged.

Good question though, one to put to Eurocopter I think.

[generalspecific]

good guess Puntosaurus. So the next part.... if you have a start where you can see proper flames out of the back of the tail pipe is it possible to be quick enough to avoid a T4 overlimit.

saw one (no not me) and then very surprised that there was no recorded overlimit, but then again there was no recorded 'flight" either...

I'm limited on trubine hours and experience but i would have expected a start "hot" enough to get a three foot flame out the back for a few seconds to be too hot for limits....

[victor papa]

A flame out the back is not necessarily a result of a hot start. It often is due to residual fuel in the MO2 after a shutdown or prolonged running of the booster pump after maintenance intervention or during ops with a fuel pump seal that is getting old thus allowing the fuel past instead of back to the tank etc and is often just residual fuel causing a secondary ignition not affecting the T4 reading due to it occuring after the probes. Not saying it is the case but have seen it many a time. On the Arriel 2 at night during a start shortly after shutdown you will be shocked to see the size of the flame when you hear the explosion sound on start-Arriel 2 no min T4 before start on AS350. Have seen a few 120's do this without T4 exceedance. The VEMD receives the T4 signal as it is displayed and it will be recorded as a over limit if it exceeded regardless of the N1. A flight is constituted from 60% N1(defaults to FLI) to 50% N1 on shutdown(defaults to 3 arc screen) and gets displayed below 10% N1 on the lower screen as the flight report. The n1 and 2 cycles is the percentage used from 0-max-0 and is the reason for it often being a decimal and not a full cycle as you do not reach max N1/2 every flt.

No expert but hopes this help. Will double chk in any case the facts and figures so do not quote me yet. Ask your engineer to print you chap 31 out of the description and operational manual and all your questions will be answered.

[John R81]

What VP said

I have only had one aborted start, for fear of temp climbing into the "expensive" zone. It was around 30% tq and did not register as a flight.

I have watched someone in my machine have a massive flame following trouble starting, and as the blades had moved, one looked to be right over the exhaust port - flame went past that. Very short lived, and nothing on the VMED report. Had it checked anyway, but no problem.

So, yes you can do that, abort the start and have no problem (reported or otherwise).

[wes120b]

To generalspecific

Without digging in the book, I believe a flight # is added when engine rotation is initiated. However, Ng and Nf cycles don’t start recording until Ng reaches 60%.

[SawThe Light]

Flames after starting

It isn’t unusual to see flames from the EC 120 exhaust after a less than perfect start. Indeed if there has been a botched start or two you can just about put money on seeing flames. The reason for the flames is the start injector ventilation process that follows a start.

Following each start (or attempted start) the start injectors are ventilated with P3 air from within the combustion chamber casing as soon as one releases the start switch. This ventilation air drives all the fuel remaining in the start injectors and their supply lines down into a small collector tank mounted under the rear part of the engine. The tank is about 3 inches long and around 2 inches in diameter. A vent pipe from the rear of the collection tank goes upwards and terminates in a rearward facing outlet inside the bottom of the exhaust tail pipe.

After a normal start the small amount of fuel drained into the collection tank evaporates and is drawn into the exhaust stream. However, if there is an aborted start or two the collector tank can end up nearly full of drained start injector fuel. If this is the case there can be a spectacular fire with blobs of flaming fuel showering the front of the tail boom when the engine finally starts.

[generalspecific]

very interesting, so that would explain what looked like a jet of fluid (fuel) squirting into the exaust stream omn a normal start.

nevver knew this, very imformative...

thx

[rogercharlie]

RE: VEMD Flight Logging

The VEMD on the 120 starts recording a new flight once Ng reaches 60% and stops during engine shutdown when Ng gets down to 50%. I'm currently training for my CPL on the bird and in 125 flight hours I have only seen one such occurrence. It was a hung start, with Ng hovering slightly above 20% after ignition. Hope that hepls.

[lamanated]

fresh from course with a recommendation for the blades

My co worker just came back from a type course and visited the blade shop, and was told to do the mod 62-011 on the blades otherwise if the blades ever need work, there is a good chance they wont be able to fix them, apparently the weights will seize inside and cant be removed.

[EN48]

there can be a spectacular fire with blobs of flaming fuel showering the front of the tail boom when the engine finally starts.

Happy thought!

[FullTravelFree]

Track & Balance

The 120 I fly is very smooth on full fuel. Whenever the fuel reaches half (top tank empty), she starts shaking in horizontal plane. I'm planning to get her balanced on the next service.

Would be helpful to know if its a common error, and if anyone has had the same and has knowledge on a solution. Thanks in advance,



FTF

[Phoinix]

Mod No. A 00075

I/m reading through the manual and i guess the modifications weren't incorporated in the revisions, so all the pink pages are still in the manual. I found all the necessary modifications effected by FLM revisions but one. The modification No. A 00075. I can not find it on T.I.P.I. either.

Any input is well appreciated.

[Rigidhead]

Full Travel Free,

How much time on the machine?
One thing to look at is to have the Frequency Adapters/Lead Lag Dampers
checked with the Trammel Tool. 1/2 a turn to 1 turn on the rod ends can
make a substantial difference to the ride quality.

Regards,

Rigidhead

[nellycopter]

Hi rigidhead

Are the frequency adaptors the things under the cabin ?
I have a problem where the left hand side of my instrument panel shakes like he'll at 70 knots and goes away about 100 knots ,

Could this be one of the adaptors needs adjustment ? I do have the later avm,s on the whole panel !

Regards

Nelly

[eivissa]

Dont know if it has been posted before, but it looks like in the future we will see a turbodiesel V8 powered EC120.

Diamond Aircraft :: Austro Engine wins EU
Rotor & Wing Magazine :: Eurocopter Restarts Diesel Engine Project