Re: Airspeed Indicator Accuracy Tolerance

Compare the reading son the airspeed, altimeter and VS while
pressurized and with the cabin vented at ambient. You could
have a static leak inside the pressure cabin that is letting
pressurized cabin air into the pilot's static line.


--
James H. Macklin
ATP,CFI,A&P

--
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But government sees it as an obstacle to be overcome.
some support
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"Bob Gardner" <bobmrg@xxxxxxxxxxx> wrote in message
news:c6-dndTuCJrUsV3enZ2dnUVZ_sGdnZ2d@xxxxxxxxxxxxxx
| And my point is that absolute accuracy is not important.
|
| Bob
|
| "O. Sami Saydjari" <ssaydjariREMOVEME@xxxxxxxxxxx> wrote
in message
| news:43C02969.40808@xxxxxxxxxxxxxx
| > Bob Gardner wrote:
| >
| >> If there is no means of adjustment, the question
answers itself. Keep in
| >> mind that the blue line is not sacrosanct...actual Vyse
will vary with
| >> weight and density altitude. The vertical speed
indicator is a much more
| >> accurate means of determining best rate of climb.
| >
| > Well, not really. My question is whether their is a
good way to measure
| > the absolute accuracy of a ASI. And my concern is that
6 nts is too far
| > off when it could make a significant difference in
performance in critical
| > situations, like single engine operation.
| >
| >>
| >> Bob Gardner
| >>
| >> "O. Sami Saydjari" <ssaydjariREMOVEME@xxxxxxxxxxx>
wrote in message
| >> news:yeRvf.31$l53.22@xxxxxxxxxxx
| >>
| >>>In my Cessna 421C, the pilot-side airspeed indicator
reads 6 nts below
| >>>the co-pilot-side airspeed indicator. When I pointed
this out to a
| >>>mechanic, he said that it was "within toleraance." He
said it was
| >>>possible that one was 3 nts high and the other 3 nts
low and so both
| >>>could be within tolerance. He added that there is no
real internal
| >>>adjustment, so there is not much he could do about it
anyway.
| >>>
| >>>Seems to me that when you are talking about a possible
6nt difference and
| >>>given the need for accurately maintain blue-line speed
in case of a
| >>>single-engine failure, it is important to know that
one's airpseed
| >>>indicator is accurate. Isn't there a way to judge true
accuracy of speed
| >>>indicators (just as there is for altimeters)? Should I
be satisfied with
| >>>my mechanic's answer and move on?
| >>>
| >>>-Sami
| >>>N5554G, Cessna 421C
| >>
| >>
|


.

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