3
$\begingroup$

See here the transcript of ending moments of Aeroflot Flight 593 . The Wikipedia writes :

(N.B.: All timestamps refer to the flight data recorder time, not GMT or local time.)

What do 2265,2266...2300.....2393..2400 mean? Maybe, they don't mean seconds since CVR can record for only 30 minutes i.e. 1800 seconds..

Improve this question
$\endgroup$
4
  • 1
    $\begingroup$ It says FDR time, not CVR time. But other A310 incidents had a 25 hour FDR, so I don't know where the 2400 is coming from. $\endgroup$
    – fooot
    Commented Jul 30, 2015 at 15:54
  • $\begingroup$ If those are minutes, then they spoke one sentence per minute. That seems very, very odd. It seems more likely that they are line numbers - i.e. each statement is simply numbered from 1 - whenever the recording ended. $\endgroup$
    – FreeMan
    Commented Jul 30, 2015 at 16:06
  • $\begingroup$ @FreeMan if they are numbering by statement, that doesn't make sense to label it "time", and then skip a bunch of them. $\endgroup$
    – fooot
    Commented Jul 30, 2015 at 16:12
  • $\begingroup$ good point, @fooot, I didn't see the missed numbers. $\endgroup$
    – FreeMan
    Commented Jul 30, 2015 at 16:15

1 Answer 1

Reset to default
4
$\begingroup$

As described, it is the flight data recorder time. The linked video in that Wikipedia article shows it as seconds. I could not find after how much time Flight 593 crashed, but 2400 seconds equal to 40 minutes.

An FDR typically records around 90 parameters, and certainly can and does monitor all of them all the time, even when several parameters change within a single second.

For the purpose of transcript for this accident, the article on Wikipedia (which is far less technical and detailed than an NTSB investigation report) omits all the entries from FDR recordings which are neither relevant to the story, nor interested to the reader. For example, the reader will care less the input from different sensors between 2303 and 2314.

Since the recording time of a CVR (30 minutes - 2 hours) is less than an FDR (25 hours), they are synchronized for an investigation. This is described here (PDF), for the investigation of Flight 1549:

The CVR and FDR data were synchronized to one another by comparing the FDR “Key VHF” parameter with radio transmissions as heard on the CVR recording. By comparing the CVR elapsed time (time since the beginning of the CVR recording) for radio transmissions to the corresponding FDR Subframe Reference Number (SRN) for “Key VHF”, a relationship between the CVR elapsed time and the FDR SRN time can be developed.

Improve this answer
$\endgroup$

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .