Alternate static source
I'm new to Sikorsky S-76D and wondering why alternate air source is not equipped with S76D?
As far as I know the regulations in FAA is as below AC 29 APPENDIX B. AIRWORTHINESS GUIDANCE FOR ROTORCRAFT INSTRUMENT FLIGHT (9)IMC Evaluation. (B) An alternate static source with a means of selecting this source must be provided for single pilot configurations. |
I am not familiar with the S-76....but this one seems obvious (though i could be wrong):
Originally Posted by twinbird
(Post 11061162)
(B) An alternate static source with a means of selecting this source must be provided for single pilot configurations.
S-76 Crew: Two pilots |
S-76 Crew: Two pilots |
In the 1960s we were briefed to get the crash axe out and smash the glass on the altimeter. (somewhere where the needles weren't)
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Originally Posted by Fareastdriver
(Post 11061261)
In the 1960s we were briefed to get the crash axe out and smash the glass on the altimeter. (somewhere where the needles weren't)
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The 76B was SPIFR but I don't recall seeing an alternate switch. Mind you, there were 645 separate switches, knobs, dials, circuit breakers and other things to twiddle, so perhaps I missed it when I counted those things one idle morning.
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Originally Posted by Nescafe
(Post 11061191)
The S76 D is certified single pilot IFR.
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Originally Posted by gulliBell
(Post 11061331)
And assuming all S76D have a dual pilot instrumentation fit out, the co-pilot side which relies on a different static source to the pilot side becomes your alternate instruments. As if your aircraft was single pilot IFR, not fitted for dual pilot operation, and the primary pilot side instruments had an alternate static source switch.
Except as provided in paragraph (h) of this section, if the static pressure system incorporates both a primary and an alternate static pressure source, the means for selecting one or the other source must be designed so that - (1) When either source is selected, the other is blocked off; and (2) Both sources cannot be blocked off simultaneously. |
Hi there,
with glas cockpit watch out for the new way of selecting alternate static source. I´m not flying the S76 - but a modern helicopter from another manufacturer - and by now its no longer just switching a guarded switch... You need to tell the computers that you are doing it in correct order of steps - or you f... up ;-) Static is then taken from inside the cabin. |
Hmmmm. So when IMC how do you "know" when your static source is "blocked"?
Asking for a friend. |
Discrepancy in altitude or rate of climb indication between co-pilot side and pilot side instruments. ASI also uses static pressure so there will be a discrepancy there as well.
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Discrepancy in altitude or rate of climb indication between co-pilot side and pilot side instruments. ASI also uses static pressure so there will be a discrepancy there as well. |
Masking tape on the static ports would be revealed during the takeoff process, I would have thought. Certainly your VSI would not be showing a climb, you should catch that very early on.
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Originally Posted by Fareastdriver
(Post 11061261)
In the 1960s we were briefed to get the crash axe out and smash the glass on the altimeter. (somewhere where the needles weren't)
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MTech,
My memory agrees with you....it was the VSI that wanted breaking. |
Originally Posted by SASless
(Post 11061897)
MTech,
My memory agrees with you....it was the VSI that wanted breaking. |
Originally Posted by gulliBell
(Post 11061834)
Masking tape on the static ports would be revealed during the takeoff process, I would have thought. Certainly your VSI would not be showing a climb, you should catch that very early on.
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SODPUD RVDT:ok: - ASI errors = Static blocked, ASI overread in a descent - Pitot Blocked, ASI underread in a descent
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Originally Posted by [email protected]
(Post 11062044)
SODPUD RVDT:ok: - ASI errors = Static blocked, ASI overread in a descent - Pitot Blocked, ASI underread in a descent
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On the 76C, the static port on the pitot tube is also Tee'd to the static port on the tail cone. Does it need to be selectable if it is coming from two locations?
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