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Sikorsky S-76: Ask Nick Lappos

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Sikorsky S-76: Ask Nick Lappos

Old 6th Apr 2005, 08:39
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We had a Skywatch on our previous aircraft and presently have a TCAS791; you get what you pay for. Skywatch is adequate for short range low level ~2-3000ft; TCAS is definitely more accurate and obviously greater range - but a lot more expensive and a bit heavier.
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Old 6th Apr 2005, 12:39
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I think I’m correct in saying that TCAS II is not an option on a helicopter – variations in predictive rate of climb with fixed-wing aircraft or something like that.

The SKYWATCH HP (TAS) is pretty popular amongst the rotary fraternity and would be worth a closer look.

Several years ago there was a limitation on the number of TCAS I operators within the UK and although restrictions were eased, it may be worth contacting the National IFF/SSR Policy Board before you plumb for a particular type.

http://www.caa.co.uk/docs/7/DAP_SSM_CAA_Doc_714.pdf
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Old 6th Apr 2005, 20:49
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Rob

A couple of suggestions:

1. Get Mr and Mrs P to look outside for you ; or
2. Prohibited area around the family compound

Unfortunately a real hazard.

One question to all:

Doesn't TCAS require transponder derived data from other aircraft? (ie. sqwarking 1200 in Class G airspace).

Alot of bugsmashers around the Hunter Valley
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Old 6th Apr 2005, 22:45
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I don't know about all TCAS models, but the Skywatch TAS we have requires other aircraft to have an operating transponder in order to see them, although they can be on any code, not just 1200. I don't know of another way to do it. With no transponder, the only thing that could possibly detect another aircraft is radar, and although we do have weather radar in our mediums, it won't pick up another aircraft well enough to do any good. Some models do use the weather radar for the display, though.
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Old 12th Apr 2005, 19:18
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SK 76 - Main Rotor Hub Problems

Hi guys,

does anyone have more information as to why Sikorsky issued an ASB requiring main rotor hubs to be inspected every day?
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Old 12th Apr 2005, 20:12
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Errrmmm....don't you inspect it every day anyway?
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Old 12th Apr 2005, 20:16
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Hilico,

the ASB requires an AME to sign the inspection every day.
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Old 12th Apr 2005, 20:21
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Sorry, half-expected it would be something like that. Does this mean the AME takes a wrench/spanner to it, rather than the ordinary pre-flight fiddle?
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Old 12th Apr 2005, 22:17
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S-76

Over here an AME is the Aviation Medical Examiner,so what do you expect him to do to it ??????/
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Old 12th Apr 2005, 23:53
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Some of the more recent hubs were machined to the incorrect thickness and there is a concern of cracking on the underside. Interestingly these were the hubs that were supposed to have a 10000hr life up from the 3000hrs. The hubs need to have an ultrasonic check prior to the AD being lifted on the effected aircraft.
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Old 13th Apr 2005, 00:40
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Sycamore,

great sense of humour, maybe you should see your AME more often.
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Old 13th Apr 2005, 08:41
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I was told some cracks had been found on an A model "in the pacific rim" recently. The aircraft in question at some point had been in an incident involving high wind (I know laid myself wide open there ) and Sikorsky were attributing the cracks to that incident. Apparently the A model head is thinner than the B and I assume the C's.

The head is to be inspected by an engineer before every flight, unless the head has had an NDT test done on it.
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Old 6th May 2005, 21:28
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HOV button on s76

On the auto pilot console on the 76 there is a hov button, bit like auto hover, but not all that accurate, when should you use this mode? is it mostly for the sar stuff or can it help in other aspects of corporate flying?
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Old 6th May 2005, 22:39
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All the other buttons on that selector have well-defined uses, but I have not yet found a situation where I have wanted to use HOV. It makes a good demonstration on conversion to type, to show a hands-off hover and even smack the cyclic to show how it restores itself, but unless you have a big airfield to drift over, it is not particularly accurate.

Too much residual drift requiring constant trim inputs for any useful hovering. Do it manually.

SAR birds have more swept-up inputs which may include doppler positioning to hold a spot over the ground. Adds a lot to the cost.
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Old 7th May 2005, 01:14
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The button is used to aid the pilot in holding a precise hover, it is not intended to allow hands off hover.
Basically, when HOV is selected, a set of acceleration sensors is linked into the sas, so that a drift produces a slight counter cyclic, automatically. It is called hover augmentation on some helos.

If you need to hold a precise hover in some bumpy conditions, it is a definate help.

The SAR mode hover uses this hover acceleration feedback, and also adds the doppler/inertial, a much more powerful sensor.
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Old 7th May 2005, 06:23
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"can it help in other aspects of corporate flying?"

It is a great help in corporate flying. While the aircraft is shut down on the ground and you are waiting for your pax, it helps to pass the time.

"On....Off.....On.....Off....."

Normally used after you have read all the newspapers.
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Old 7th May 2005, 10:03
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If you are talking about the SPZ 7600 AFCS, I thought that this button was originally marked 'HOVER' and on later versions of the system became renamed as 'VELOCITY'. It's a nice way to allow engineers to fly the A/C smoothly at low speeds, beeping it into a hover with the trim button. I've not seen it used by real pilots too often though, I guess they can probably hover the aircraft using their own on-board accellerometers!
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Old 8th May 2005, 12:50
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I will have opportunity to try this as an 'augmentation'. I do hover exit work occasionally. That button has always puzzled me too. The next time I am fighting the gusts trying to keep one wheel on a rocky outcropping, I will engage this mode, and report back on the difference it made.
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Old 8th May 2005, 15:58
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hovering,


Might I suggest you try it before you get the wheel onto the craggy outcrop - it might not be a good place to find out you don't like it!
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Old 9th May 2005, 18:07
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wizzard, good idea...
So I went out to do a limiting check today, and tried HOV out for a few while over the threshold of the runway in 10Kt winds.
I noticed little difference. Engaging COLL driving made us go up and down a few feet while in a 5-10 foot hover....good for a laugh.
My final thoughts? It certainly didn't make thinks worse laterally, but I did not notice much improvement. I wouldn't use the collective driving/RAD alt. mode too low....
I was hoping it would smooth out some of the lateral dancing the A/C likes to do in the wind as air swirls over the tail rotor...no luck there.
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