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Cockpit Flight Recorder question

Qualiall

Member
I apologize if this was addressed in another thread. I was wondering if after such a long flight, possibly after everyone aboard was dead, and seeing as the cockpit voice recorder only records the last two hours, that recovery of this would not answer any questions, or there would be a way to access overwritten data?

When I was younger, I remember discovering that when recording on cassette tape, if I pressed the record button so it wasn't fully depressed that I could overlay sound upon what was recorded before. (had lots of fun remixing songs that way) . So I would imagine recovering overwritten data on a magnetic tape would be easy.

But with solid state technology, is this possible? From what I understand about solid state is that data is completely overwritten.
 

TWCobra

Senior Member.
It is over written every two hours but I believe that with digital processing they may be able to extract some data. The most important data though will be the Flight Data Recorder, which has the last 25 hours of flight time recorded.
 

Svartbjørn

Senior Member.
So... just to clarify Cobra.. there's more than one recorder? One's a Flight Data Recording, which records everything the mechanical aspects of the aircraft were doing... button presses, pilot input, altitude, speeds, (vectors?) etc.. and then there's the Voice Recorder, which records all the sounds and conversations etc in the cockpit? Or is that over simplified?
 

WeedWhacker

Senior Member
So... just to clarify Cobra.. there's more than one recorder? One's a Flight Data Recording, which records everything the mechanical aspects of the aircraft were doing... button presses, pilot input, altitude, speeds, (vectors?) etc.. and then there's the Voice Recorder, which records all the sounds and conversations etc in the cockpit? Or is that over simplified?

Yeah, the FDR and CVR are all digital nowadays (compared to 1960s and 70s era, with foil tape and needles scratching into it for the FDR, and a continuous-loop magentic tape-- like an old 8-track cassette -- that had about 30 minutes of recording time).

You're spot on RE: the FDR - And, even more than you mentioned. LOTS of data points can be monitored, and recorded. (You've no doubt already learned of the ACARS transmissions that routinely send "Status Reports", too). Also nowadays, just about every airliner also has a QAR (Quick Access Recorder) which we call a "snitch"...this could also be called an "FDR-lite". Its data is regularly downloaded by the avionics specialists in the Maintenance Department. Then, it is checked for any "gotchas" such as flap limit overspeeds, unstabilized approaches, etc. This info is part of an airline's "Continuing Maintenance Program" (or some similar terminology) and it is designed to lower costs (of course) due to the increased monitoring.

Particularly egregious excursions from SOPs are flagged....usually "de-identified" (but this is per a Collective Bargaining Agreement, and will vary from company to company). This "de-identified" data is often used in annual refresher training ("re-current training") whenever a 'trend' is seen.

Also, SOPs are sometimes altered, due to observed 'trends'. Of course, if a really bad violation has occurred, then in concurrence with the Union, the responsible crew are called in, and either disciplined, and/or given "extra" training. The FAA can also take administrative action.


...and then there's the Voice Recorder, which records all the sounds and conversations etc in the cockpit?

When you get a chance to read an NTSB accident report (for example) and the CVR transcript, you will see acronyms like "CAM"....that is 'Cockpit Area Microphone'. Yes, that is one thing recorded by the CVR....also, all of the audio channels (VHF Comm #1 and #2...and #3 if installed ...HF #1 and #2, etc)....and the Interphone(**)...that's the way to communicate within the jet (Flight Deck to cabin, and within the cabin, F/A to F/A....and we, of course, can monitor that on one of our audio channels....when I was particularly bored, I'd have that in my earpiece, and also to have a hint about what was going on "back there"), and to the ground crew when they have headsets plugged in....and of course, all PAs are recorded too.

(**)BTW, next time you fly, note the chimes in the cabin. The two-tone "Bing-Bong" doorbell sound is the Interphone call. You will also see lights in the ceiling...pink (IIRC) is the Interphone, within the cabin. Blue means the cockpit is calling. A single chime (if not a seatbelt sign turning on or off) is a passenger call from the PSU above their seat...white (unless they're in the Lav....which, of course, is ......yellow! ;)

PPS- The colors might vary between companies, per their preferences. But, yellow never changes! :D
 
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MikeC

Closed Account
SOPs - Standard Operating Procedures :) Just another of the myriad TLA's in aviation

(TLA - Three Letter Abbreviation)
 

Svartbjørn

Senior Member.
This is probably way off topic... but why the hell are they called black boxes when they're usually yellow or orange? Was that a media thing because black box sounds better than orange box?
 

Svartbjørn

Senior Member.
Ahhhh okok, Ive read all taht before but I wasnt sure how much of it was urban legend and how much of it was factual.. thanks Mike.... and deirdre
 
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