and i still would like to learn why the CVR was damaged:
TSO Date Impact requirements Fire test requirements
C51 Aug. 1958 100G for 11ms The recording medium shall remain intact so that intelligence can be analyzed after the recorder has been exposed to flames of 1100 C, enveloping at least 50% of the outsuide area of the case for 30 minutes.
C84 Nov. 1963 100G for 11ms [same as TSO C51]
PLUS: Any cracks or holes resulting from the impact shock test be included in the 50% flame envelopment, and that the recorder be allowed to cool naturally.
C51a Jan. 1966 1000G for 5ms [same as TSO C51]
PLUS: Impact shear ~ 500lbs. from 10',1/4" pin adn Static crush ~5000lbs. 3 sides, 5min.
C123 May 1991 1700G for 6.5ms 1100 C, flame enveloping 100% of the outside area of the case for 30 minutes, 50000BTU/h thermal flux.
Note: does not require TSO C124 fire test protocol. (Ref. EUROCAE Doc ED-56)
C124 Feb. 1992 3400G for 6.5ms [same as TSO C123]
EXCEPT thermal flux must be measured by a water calorimeter of the size and shape of the recorder. (Ref. EUROCAE Doc. ED-55)
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References:
NTSB Safety Recommendations A-92-45 through -48 / National Transportation Safety Board (NTSB), May 28, 1992
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If i assume that the cvr was located in the back of the plane
which separated from the rest of the plane while still on the runway two questions come to mind:
1. How hard was the impact when the tail separated ?
I assume by far not as hard as coming down vertically from
some 1000 feet ....
2. Was the tail exposed to fire ?
or was the CVR simply not working ? i'm not sure whether
the CVR is an item in the MEL.
sorry if this was discussed anywhere in the 30+ pages before ...