The PC-9 Martin Baker seat and how it works
Specifications Mk 11 (SA11A)
Operating ceiling 40 000 ft
Minimum height/speed Zero/60 KIAS in near level attitude
Crew boarding mass range 60 to 126.7 kg
Crew size range Specific crew size range
Maximum Speed for ejection 400 KIAS
Parachute type GQ Type 1000 Mk2
Parachute deployment Drogue assisted
Drogue parachute type Yes
Drogue deployment Fired by cartridge generated gas Initiated by trip rod
Harness type Combined
Ejection seat operation type Ejection gun
Ejection gun Single
Ejection initiation Handle on seat pan initiates gas operated seat firing system
Automatic back-up unit No
Electronic Sequencer No
Barostatic time-release unit Fired by cartridge generated gas initiated by trip rod
Timers Drogue gun time delay, command delay breech
Seat adjustment Up/down Actuator operated 28 Vdc
Arm restraints Firing handle remains attached to seat pan to help prevent flailing
Leg restraints Yes, two garters
Oxygen supply Bottled emergency oxygen Connection for main oxygen supply
Personal survival pack Equipped for desert survival, manual deployment
Aircrew services No
Command ejection Yes
Canopy jettison No
Miniature detonating cord No
Canopy fracturing system Canopy breakers
Interseat sequencing system No
How it works
- Seat firing handle pulled causing seat initiation cartridge to fire
- Command firing initiated (if selected)
- Harness retraction unit operated
- Primary cartridge fires
- Top latches disengage, seat rises up rails, secondary cartridges fire progressively
- Canopy breakers shatter canopy
- Drogue gun time-delay mechanism initiated by trip rod
- Barostatic time-release unit (BTRU) initiated by trip rod
- Seat services and command ejection quick-disconnects disconnected
- Emergency oxygen supplied to aircrew
- Leg restraint lines restrain aircrew’s legs, lower attachments shear
- Drogue deploys after delay, to stabilise and decrease velocity of seat
- Barostatic time release unit monitors the altitude
- Above pre-determined altitude -
- Seat falls, stabilised by drogue
- Emergency oxygen supply continues
- Below pre-determined altitude -
- BTRU mechanism operates, cartridge fires (If BTRU fails manual deployment also available by pulling manual override handle)
- Drogue shackle freed
- Parachute mechanical lock freed
- Upper harness locks released
- Lower harness lock mechanism releases lower harness lugs, negative-g strap and leg restraint lines
- Aircrew momentarily held in seat by sticker straps
- Drogue extracts and deploys the main parachute canopy
- Main parachute canopy fully deploys and lifts aircrew and personal survival pack (PSP) from seat.
- Reaction to sticker clips ensures divergence of aircrew and seat
- PSP manually lowered on drop line below aircrew
- Normal parachute descent follows
- Manual opening of PSP