Sikorsky S-76: Ask Nick Lappos
I reckon it was a 'go-slow' alarm as he was flying it at R22 speeds. Seemed to be going slow for a 76 unless there are restrictions wherever it was.
One well known offshore co. 76's have a nose up restriction as they fitted the ADELT under the tail!!! Really the most sensible place to put it...NOT
One well known offshore co. 76's have a nose up restriction as they fitted the ADELT under the tail!!! Really the most sensible place to put it...NOT
No,no warning light, but Mr. EGPWS sometimes reminds us with a "tail too low" message. ( by the way,that's the only situation when I find a "male" EGPWS a better choice than a "female" ....
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One result of impacting the tail of the S76 on the ground is a rippling of the skin of the tail boom where it mates to the cabin area and possible internal damage requiring a period on the ground. Have seen this type of damage a few times last few years. Did not the Royal Flight S76 this also?
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Is the caution still there or has it been removed from the normal procedures section?
I can't seem to find it anymore.
Does it specifically mention 10 degrees nose up within 30'AGL?
I can't seem to find it anymore.
Does it specifically mention 10 degrees nose up within 30'AGL?
76C++ RFM page 2-30
CAUTION
During landing and operations near the ground, avoid
attitudes greater than 10° nose-up, to reduce possibility of
tail to ground contact, especially during operations at aft CG.
CAUTION
During landing and operations near the ground, avoid
attitudes greater than 10° nose-up, to reduce possibility of
tail to ground contact, especially during operations at aft CG.
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Sorry lads...don't have a flight manual with me at present....did it ever mention 30' AGL....got some beer riding on this one.
Nick did the original caution in the A model mention anything about 30' AGL?
Nick did the original caution in the A model mention anything about 30' AGL?
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XNR,
The EGPWS has that rule in it as an extra, but the caution has no altitude associated with it, since the actual contact point is 14.7 degrees just as the main gear, oleos fully extended, touches. I would imagine that Adelt might cut the angle a bit.
Note that check's comment on bending the tailcone is simply not true. If the aircraft has a very hard landing on the mains, it might show the hard landing by having a dimple on the underside of the tail cone due to the slight downward bending of the cone (not due to touching the ground).
The EGPWS has that rule in it as an extra, but the caution has no altitude associated with it, since the actual contact point is 14.7 degrees just as the main gear, oleos fully extended, touches. I would imagine that Adelt might cut the angle a bit.
Note that check's comment on bending the tailcone is simply not true. If the aircraft has a very hard landing on the mains, it might show the hard landing by having a dimple on the underside of the tail cone due to the slight downward bending of the cone (not due to touching the ground).
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Just wondering what brought about a change to procedures regarding engine chip-lights in A models (maybe other models too?)? Now a new revision to the RFM tells us to pull that engine to idle first before touching with the cb.
What the deuce? Is it just assuming the worst that that engine is about to crap out anyways so may as well be in OEI flight asap vs wasting time playing with the cb first?
What the deuce? Is it just assuming the worst that that engine is about to crap out anyways so may as well be in OEI flight asap vs wasting time playing with the cb first?
Canuck guy,
Maybe is it a preccautionary procedure; if the chip is caused by ,let's say, a free turbine bearing things will deteriorate very quickly with a possible fire or free turbine explosion and for sure engine shut-down.
Engine on idle is certainly a better configuration to assess the situation and follow up with the procedure.
I haven't seen this amendment on arriel 2S1, do they still stipulate to make sure OEI flight is possible or is it an immediate action ?
Maybe is it a preccautionary procedure; if the chip is caused by ,let's say, a free turbine bearing things will deteriorate very quickly with a possible fire or free turbine explosion and for sure engine shut-down.
Engine on idle is certainly a better configuration to assess the situation and follow up with the procedure.
I haven't seen this amendment on arriel 2S1, do they still stipulate to make sure OEI flight is possible or is it an immediate action ?
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Front door window
Hi Nick and all. On the S76 all the rear windows can be jettisonnable (offshore), but not the one on the front door, why is that. My guess is too much pressure, but it is just a guess.
FH
FH
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FlyingHead,
The rear windows jettison because the sliding door does not. The entire pilot door assemblies jettison. On aircraft with a rear hinged door, the entire door jettisons, as well.
Canuck Guy,
I have no recent info on that. I do know that the C30 family chip procedure once a chip is confirmed was always to go to idle and/or shut it down, so the idea of going to idle when you pull the CB is not a bad idea. Frankly, this is in keeping ahead of the aircraft, since you will be in a regime where a failure is of low consequence, since you are already in OEI flight.
At 30,000 rpm, things happen quickly, so I would guess going to idle first saves many seconds of running time, valuable time since while pulling the CB your head is turned the wrong way if the engine should quit.
The rear windows jettison because the sliding door does not. The entire pilot door assemblies jettison. On aircraft with a rear hinged door, the entire door jettisons, as well.
Canuck Guy,
I have no recent info on that. I do know that the C30 family chip procedure once a chip is confirmed was always to go to idle and/or shut it down, so the idea of going to idle when you pull the CB is not a bad idea. Frankly, this is in keeping ahead of the aircraft, since you will be in a regime where a failure is of low consequence, since you are already in OEI flight.
At 30,000 rpm, things happen quickly, so I would guess going to idle first saves many seconds of running time, valuable time since while pulling the CB your head is turned the wrong way if the engine should quit.
Last edited by NickLappos; 30th Nov 2007 at 11:49.
4p vibration- S76
Hello all,
I would like to know what is the optional LVA (lateral vibration absorbers) function ? Are they an optional device, complementary to the VTA, to enhance the cabin vibration level or else?
We are experiencing, on one of our S76, a sudden increase of a 4P vibration, in consecutive sequences at around 135 Kts, mainly felt in the nose and cockpit section.
The track and balance are within limits, all other checks, inspections and settings have been tried without success.
I am curious to know if these LVA have something to do with this kind of vibration and if one of you ever experienced the same symptom.
Thanks
(sorry I couldnīt find the S76 thread back )
I would like to know what is the optional LVA (lateral vibration absorbers) function ? Are they an optional device, complementary to the VTA, to enhance the cabin vibration level or else?
We are experiencing, on one of our S76, a sudden increase of a 4P vibration, in consecutive sequences at around 135 Kts, mainly felt in the nose and cockpit section.
The track and balance are within limits, all other checks, inspections and settings have been tried without success.
I am curious to know if these LVA have something to do with this kind of vibration and if one of you ever experienced the same symptom.
Thanks
(sorry I couldnīt find the S76 thread back )
...and I thought that a 4p vibe was totally normal in a 76? along with all the other vibes that it produces even tho all tracked and balanced. Smoothest S76 I have flown so far is the sim at Flight Safety in WPB. I'll have to have a word with our engineers then.
Our S76 are C+, they usually fly smoothly and are pleasant to fly at all speed as long as engineers take a carefull and regular care of the vibration level adjustment.
They are not equipped with the upper (5P) bifilar, nor with LVA.
This 4P vibration appeared suddenly on cruising flight, beeing rather worrying.
It feels a bit like a fixed wing post stall buffeting, but not constant, in few seconds sequences in the 135 Kts IAS range.
They are not equipped with the upper (5P) bifilar, nor with LVA.
This 4P vibration appeared suddenly on cruising flight, beeing rather worrying.
It feels a bit like a fixed wing post stall buffeting, but not constant, in few seconds sequences in the 135 Kts IAS range.
Last edited by cpt; 29th Jan 2008 at 06:47. Reason: 5P "upper" bililar
