Re: Peruvian 757 crash -- possible cause reported

Date:         20 Nov 96 05:48:28 
From:         "David G. Davidson" <>
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>Altitude information would be better but both the altitude and
>vertical speed comes via the staic port.

After looking this is up again I see this going to require somemore

The ADCs feed:

Altitude Rate
True Airspeed

to the IRS. The IRS in turn outputs:

Mag Heading
Vertical Speed
Angular Rates
Linear Acceleration

Present Position
True Heading
Ground Track Vector
Wind Vector

Whether the IRS uses any of the ADC info to calculate VS is unclear. The
IRS should certainly be able to figure it out using the accelerometers.
I do know that we've never fixed a VSI problem by changing the ADC, only
the IRS has fixed this. I'm only talking about 757/767 here.