NNC 0.x [Emergency Descent]
PRIOR DESCENT - Advise ATC about rapid descent
- Advise cabin crew using company SOP and call-outs
DURING DESCENT - confirm heading and altitude to ATC
- verify minimum safe altitude
- obtain the area altimeter setting
- accomplish the NNC
! If structural integrity is in doubt (e.g. door open annunciation or heavy vibrations) limit airspeed to 250kts. In this case, consider extending the landing gear (speed below 270 kts placard limit) to increase the descent rate. Raise the landing gear after the level-off (speed below 235 kts placard limit.)
AFTER DESCEMT
- Advise the CCM that oxygen masks can be removed
- Request radar vectors from ATC to suitable diversion aerodrome
- Determine the cause of decompression (structural damage, outflow valve, ...)
If there is no obvious cause for the decompression, have the cabin crew perform a visual check for possible airplane structural damage. With the main outflow valve full CLOSE, structural damage should be suspected.
! Flight Crew should not remove their oxygen masks above 10,000 ft. In case of a level-off above this altitude (e.g. for obstacle clearance), keep the mask on. Consider selecting the mask to NORMAL instead of 100% to conserve oxygen.
Crew oxygen supply can be shutdown by closing the doors and then pushing the Reset/Test switch. (the mask may remain outside)
(As installed) With the hot microphone feature installed, you must push the Reset/Test switch to re-establish communications via the microphone boom.
Request a status report from the cabin crew on the number of injuries. Advise ATC about the assistance you require upon arrival.
With the airplane depressurized, limit the rate of descent to 1,000 fpm below 10,000 feet. You need about 40 NM for a continuous descent from FL100 to sea level.
Rule of thumb to calculate the fuel required at FL100 :
Fuel (kg) = 10 x distance to diversion field (NM)
Fuel (lbs) = 22 x distance to diversion field (NM)(BBJ-BB2) (As Installed) After rapid depressurization, only engine bleed air is available for auxiliary fuel transfer. The fuel transfer rate is reduced by approximately 50 %. When the FWD and/or AFT Auxiliary Fuel Transfer Switches are selected to AUTO the FEW and/or AFT Bleed Air Switches shall be placed in the OVRD position.
Refer to FCTM 7.x [Rapid Descent] for additional information.