744rules From Belgium, joined Mar 2002, 406 posts, RR: 0
Reply 1, posted (11 years 3 months 3 weeks 21 hours ago) and read 2212 times:
I think this is just the switch to activate the cvr/cdr. If I recall well, cvr/cdr are positioned in the rear of the a/c, as statistics shows that this parts have the least damage in case if a crash. On a 737-400 it is located in the aft lower hold.
B747skipper From , joined Dec 1969, posts, RR:
Reply 2, posted (11 years 3 months 3 weeks 21 hours ago) and read 2216 times:
Bonjour Frederic -
What you see there is indeed the "flight recorder" in a DC9...
Actually it is merely the panel to "program" it...
Print the day/date, flight number etc...
You say correctly there are 2 "black boxes"...
One is a flight recorder, the other one a voice recorder...
By the way, with a name black boxes they are generally bright orange color.
The flight recorder operate any time the airplane is powered by its engine generators (not APU or External Power) probably... It collects basic numbers about airplane speed, altitude, acceleration, vertical speed, flight controls...
The voice recorder is operated from the first check list until the completion of the flight. It can be erased voluntarily, maybe with APU or External Power connected, or maybe the parking brake set (I dont know the DC9, again)... A voice recorder only keeps the last 30 minutes of cockpit noises (voices) and radio communications, everything older than 30 minutes is erased by new recording (continuous loop metal tape)...
I dont know where the "orange" black boxes are located in a DC9, electronics compartment or in the tail, in the 747, the "black box" is in the tail near L-5 door...
AAR90 From United States of America, joined Jan 2000, 3451 posts, RR: 48
Reply 4, posted (11 years 3 months 3 weeks 14 hours ago) and read 2166 times:
Wow, never saw one with all that stuff. AA airplanes have just a test switch for Flight Recorders. Flight Recorder activation is automatic and usually beings with first engine generator being brought on-line. It is as previously mentioned, just the control head for the flight recorder. The actual "black box" is located in the DC-9's tail cone area behind the pressure bulkhead/door.
The Voice Recorder control head is located to the left and up (back) of the Flight Recorder panel. You can easily see the Cockpit Area Microphone sticking out. It has a test button and gauge to see if it is working and an erase button to supposedly (I'm told it doesn't work very well) clear the tape. The actual "black box" is also located in the DC-9's tail cone area.
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Airplay From , joined Dec 1969, posts, RR:
Reply 6, posted (11 years 3 months 3 weeks 3 hours ago) and read 2113 times:
As with anything "aviation" flight recorders are found in several different configurations.
The latests systems often consist of combination CVR/FDR units. Some airworthiness authorities require dual installations in this case.
The average recording length these days is 1 or 2 hours for CVR and 54 hours for FDR. New installations no longer use any type of tape or metal recording medium. They use solid state digital memory. Modern installations record at least 88 distinct parameters and if the aircraft contains databusses, they record even more. I have seen a VARIG installation that recorded 500 parameters.
The required parameters varies from country to country.
Modern CVR installations must also record continuous audio from the flightcrew's boom microphones in most cases which was not required before.
Many civial aviation authorities around the world have adopted Eurocae ED-55 and ED-56A as standards for installing, and maintaining flight recorders in aircraft. These documents (not available on the internet) contain such things as acceptable means of beginning and ending the record cycle and appropriate areas to install the units.
Note that many older aircraft still use 11 parameter FDRs that use magnetic tape which records parameters digitally.
You can check out FAR 121 and FAR 135 for required parameters in the FAA world if you're interested.
Just out of interest, the term "black box" was used by maintenance people to describe any LRU (Line Replaceable Unit) not just flight recorders. The media who were only involved or concerned about LRUs after accidents, adopted the term to mean only the flight recorders. Most (not all) civil aviation authorities require that the FDR and CVR be painted orange or yellow and be fitted with reflective tape and a placard that says something like "FLIGHT RECORDER DO NOT OPEN''.
Other "black boxes" (other than flight recorders) are still often painted black...but many are blue or other colors too!
You can see the panel with the following label : 'Cockpit Voice Recorder'. This
panel commands one of the black boxes : the one which record voices of pilots
and noise in cockpit. One this panel, you can see (left to right) a mike which
record noises in cockpit (alarms, engines, switchs, etc...). Next, you can see
an indicator which show the empty part of the CVR memory. This black box is only
able to record between 30 minutes and 2 hours. The red Push- Button erases the
black box, and the green make a test.
The panel labelled 'Flight Recorder' permit to send specific informations to the
Flight Data Recorder (FDR), the other black box. You can inform this black box
of date, flight number, etc... The FDR record a lot of parameters : altitude,
speed, heading, autopilot status, failures, etc...
Ybacpa From United States of America, joined Feb 2001, 1108 posts, RR: 1
Reply 8, posted (11 years 3 months 2 weeks 6 days 11 hours ago) and read 2050 times:
Building on this thread a little:
Does anyone know why there are not duplicate voice and data recorders? It seems like a number of the recent accidents have had problems with retrieving data from one or both of these units.
Also, with all the redundancy designed into modern airplanes, it strikes me as odd that this, at least to a laymen, is not redundant.
Thanks for any insight.
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Airplay From , joined Dec 1969, posts, RR:
Reply 9, posted (11 years 3 months 2 weeks 6 days 11 hours ago) and read 2045 times:
Flight recorders do not contribute directly to the safe operation of the aircraft. Thats is why they are required by FAR 25 which is a design standard. Rather, they are required by various operating standards like FAR 121 or FAR 135.
Redundancy is typically only considered if the failure of a unit contributes to a hazardous situation in operating the aircraft.
Many problems with retrieving data from flight recorders are associated with the severity of the crash, and some older designs that use recording mediums that are easily damaged.
Modern recorders are much more robust and resistant to damage.
Jsuen From United States of America, joined Aug 2001, 211 posts, RR: 0
Reply 11, posted (11 years 3 months 2 weeks 6 days 10 hours ago) and read 2044 times:
A major problem with CVRs is that they are not properly switched off after an incident or minor accident. The NTSB is pushing for carriers to ensure the CBs are pulled when necessary. Also, new two-hour recorders should help.
CVRs and FDRs are run off aircraft power which can fail during an accident. While it is impractical to run every single aircraft measurement system off a battery, there is talk of adding backup batteries to CVRs.
Most issues with systems relate to improper maintenance. I remember an accident when a single capacitor opened on an older CVR. The end result was that it passed self tests, but did not record any information. Most recently, the lack of CVR information on the crash of a Jetstream was blamed on a failure to conduct tests after maintenance.
Trains have FDRs too, called Event Recorders. Like FDRs, the new models are solid state recorders which can monitor hundreds of parameters for several days.