Here you find some details about the deployable recorder installed on the F/A-18:
http://safetycenter.navy.mil/aviatio...loads/FA18.pdf The expected deployment envelope is enclosed as Appendix B.
Some additional information:
Deployable Flight Incident Recorder Set (DFIRS)
The DFIRS system consists of the Deployable Flight Incident Recorder Unit (DFIRU), the data transfer interface unit, and the pyrotechnic release system. The SDR consists of the flight incident recorder memory, beacon, battery, and antenna, all contained in an deployable aerodynamic airfoil located on the top on the fuselage between the rudders. DFIRS stores up to 30 minutes of flight incident data and deploys this data along with a rescue beacon, via the airfoil, when activated. The SDR is deployed upon pilot ejection or ground/water impact. The data stored on the flight incident recorder (FIR) is gathered by the mission computer from existing systems on the aircraft. DFIRS records flight data, cautions, advisories, and spin data. The FIR memory wraps around to the beginning when the end of memory is reached. Only the last 30 minutes of each flight is retained. DFIRS data recording starts when both throttles are advanced past 90° power lever angle (PLA), when ground speed exceeds 50 knots, or when WoffW and airspeed is over 80 knots. DFIRS recording stops 1 minute after WOW, both throttles are less than 90° PLA, and the ground speed is less than 50 knots. All data during SPINs and MECH ON cautions are automatically recorded.
For civil deployable recorders, the following details can be found in EUROCAE ED-112:
3-1.7 DEPLOYMENT CRITERIA
a. The design characteristics of a deployable recorder shall result in the recorder landing clear of the aircraft wreckage.
b. The unit shall incorporate flight characteristics that enable it to rapidly establish a flight trajectory that clears the airframe.
c. The unit shall not be given sufficient initial momentum on deployment such that its release could endanger ground support personnel or the aircraft itself.
d. Sufficient sensors shall be installed and located to detect impact, and water immersion resulting from an accident.
e. There shall be no means for manual deployment.
3-1.7.1 Impact Initiation
a. Frangible or deformation sensors shall be installed in both the nose and the tail of the aircraft.
b. Sensors may be installed at other locations based on structural analysis and review of typical aircraft crash landing orientations.
NOTE: Impact sensors should be designed such that they will only trigger when the structure has been significantly deformed (representing a catastrophic accident). Negative acceleration sensors should not be used.
3-1.7.2 Hydrostatic Initiation
For both fixed and rotary wing aircraft, a hydrostatic sensor shall deploy the recorder at a depth of 3 m or more.
The attached ELT must operate for at least 150h.
Of course, an aircraft equipped with a deployable recorder should have an ULB fitted somewhere on the airframe, so that the wreckage can be located if under water.
BR,
aerolearner