MK3 EJECTION
SEATS
First Mk3 ejection was on 1st November 1955 255 lives saved using a Mk3 ejection seat

The Mk2 automatic seats were successful in providing safe escape from the aircraft in service at the period, but there was still room for improvement at very low altitudes and very high speeds. In addition, the advent of aircraft such as the Javelin and the V bombers with their high fin projections and higher operating speeds, made it necessary to increase the height of the ejection trajectory, any increase also improving the chance of a successful ejection at low altitudes.

Operating Ceiling 40000+ ft (12,192m)
Minimum height/Speed Unknown
Crew boarding mass range 70.4 to 101.7kg
Crew size range 5th to 95th percentile
Maximum Speed for ejection 400+ KIAS
Parachute type Irvin I 24
Parachute deployment Drogue assisted
Drogue parachute type Duplex drogues 22 in. and 5ft
Drogue deployment Drogue gun. Cartridge generated gas. Initiated by 0.5 sec clockwork time-delay, tripped during ejection sequence
Harness type Separate parachute, seat harness
Ejection seat operation type Ejection gun
Ejection gun 80ft/sec. One primary cartridge, two or four, secondary cartridges, 72 in. stroke
Ejection initiation Face screen and seat pan firing
Barostatic time-release unit Yes, tripped during ejection sequence
Manual override handle No, but provision for manual separation
Timers Time-release unit for man/seat separation
Seat adjustment Up/down
Arm restraints No
Leg restraints Yes, two garters
Oxygen supply Bottled oxygen
Personal survival pack Liferaft pack
Aircrew services Personal equipment connector (PEC) provides connections for
- main oxygen
- emergency oxygen
- air ventilated suit
- anti-g suit
- mic/tel
Canopy jettison Option, aircraft variant dependent
  • Canberra
  • Hawker Hunter
  • Valiant
  • Vampire
  • Supermarine Swift
  • Hawker Hunter
  • Javelin
  • Vulcan
  • Victor
  • Fairey Delta 2
  • Bristol 221
  • Handley Page
  • The pilot pulls the face screen seat firing handle
  • Canopy jettison initiated (if fitted)
  • Ejection gun fires and the seat moves up the guide rails
  • Emergency oxygen tripped
  • As seat rises, static line initiates time-delay which fires drogue gun after 0.5 seconds
  • As seat rises, static line initiates time-release unit
  • 22 in. dia then 5 ft dia drogues stabilise and slows the seat down

Above 10000ft

  • Barostat prevents operation of time-release mechanism

Below 10000ft

  • 1.5 sec (3 seconds on earlier Mk3 seats) after initiation of time-release unit the plunger releases scissor shackle to transfer pull of drogue to lifting lines of parachute, releasing it from seat
  • Release face blind
  • Drogues deploy main parachute and pilot separates from seat
  • Normal descent
  • In the event of failure of time-release unit, aircrew pulls D ring on parachute harness. This pulls slide disconnect pin which disconnects withdrawal line from parachute
  • Pulling D ring also removes canvas flap from second D ring
  • Pilot pulls second D ring to operate parachute
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