Eject, Eject, Eject

Pulling the firing handle starts a series of events which, in 2. 5 seconds, will have the pilot descending in a developed parachute. On some aircraft the canopy is jettisoned prior to ejection, on others the seat punches through the canopy, and on others an explosive cord breaks the canopy during the ejection sequence. The seat is initially unlocked from the aircraft and propelled upwards by three gas-operated cartridges at a rate of 17 ‘g’. As this occurs, the pilot is pulled into his seat by the power harness retraction unit, and his legs are drawn tight against the seat so that they will not catch on the cockpit sides. (Some aircraft have similar arm retraction units. ) The pilot’s oxygen, microphone and anti-‘g suit connection are then broken and emergency oxygen is connected. The drogue gun and barostat time-release unit are armed, and the seat rises up the telescopic ejection gun tubes which serve to control the trajectory. As the tubes separate, the rocket firing static cable separates to fire a rocket pack through a ‘remote rocket initiator’. The 4500 lb st rocket motor pushes the seat upwards for 0. 25 seconds at 14 to 16 ‘g’, coming on at a rate of 180 to 210 ‘g’ per second. The drogue gun then fires to release a small drogue chute which pulls out a larger stabilising drogue chute from the parachute pack. If the ejection is above a certain altitude, a scissor shackle retards mairi parachute deployment until the seat descends to a pre-set altitude, whereupon the barostat time-release unit fires to release the main chute and release the pilot’s harness. This separates the seat from the pilot, but as the seat drops away it serves one more useful function by removing arming plugs from the personal survival pack, inflating the pilot’s life jacket, and operating his personal locater beacon. A liferaft in the personal survival pack automatically inflates if the pilot comes down in water.

Development of the Ejection Seat

Mr Martin’s first seat, the Mk 1, was ordered for all front-line Royal Air Force and Royal Navy jet fighters in 1947. The Mk 1 was propelled by a single explosive charge (similar to a very large shotgun cartridge), and fired by a pull-down handle, incorporating a face blind, on top of the seat. The purpose of the blind was to protect the pilot’s face from windblast and flying debris. After ejection, the pilot was left to his own devices to manually separate from the seat and deploy his parachute.

The Mk 2 seat was developed to overcome the problems of manual operation. Some pilots were killed after ejecting from their aircraft in Mk 1 seats when they accidentally released their parachute harness instead of the seat harness, and others did not reach their ripcord handles in time after low-level ejections. The solution was to provide automatic seat separation and parachute deployment, and additionally, a barostatic time-release unit was provided for high altitude ejections so that the survivor would free fall in the drogue stabilised seat, breathing oxygen from an emergency bottle until he reached a pre-set height (usually 12,000 feet) where the barostatic device would release the main chute. This system solved the problems of survivors freezing or becoming hypoxic in the cold thin air at high altitudes. The Mk 2 seat was first fitted to RAF Hunters and Javelins. The RAAF’s Canberras were also fitted with the Mk 2.

Meanwhile, the Americans were producing various types of seats for their own aircraft, which were fired by mechanisms in the armrests. The RAAF Avon-Sabres were fitted with this type of seat. Pulling the left grip up once armed the canopy, pulling again jettisoning it, putting the right grip once armed on the seat, and pulling again initiated ejection. This type of seat suffered from the complexity of its operation.

Martin-Baker was still improving its design and produced the Mk 3 for the RAF’s V-bomber fleet. This seat was fitted with a three-tube telescopic firing gun (instead of two tubes), giving a precise trajectory during ejection so that the crew member would clear the bomber’s high tail. Unfortunately, for cost reasons, the rear crew members were not provided with seats and were expected to bail out conventionally. The Mk 4 seat was the next development and entered service in the English Electric Lightning, de Havilland Sea Vixen, and Aermacchi 326. The new seat was lighter, and incorporated a ‘g’ switch in the time release unit which delayed the main parachute deployment (at high speeds) until the drogue chutes had decelerated the seat to a safe speed. The Mk 4 seat provided a safe ejection from ground level at a minimum of 90 knots, or 0-90 capability. This seat was fitted to the RAAF’s Macchi and Mirage aircraft. The French also chose the seat for many of their aircraft, including the Mirage Ill, IV, F1 and Etendard IV.

The Mk 5 was a similar design to the Mk 4, but was produced to American specifications, and differed mainly in harness and survival pack contents. The Mk 5 was to become standard equipment for most US Navy aircraft of its time, including the F-4 Phantom, F-8 Crusader and A-6 Intruder. The seat also had 0-90 capability.

With the advent of V/STOL aircraft projects, and the demanding needs of carrier-borne aircraft, Martin-Baker developed the zero-zero seat – one that would safely eject its occupant from a stationary aircraft at ground level. To achieve this, the cartridge firing system was superseded by a rocket system. A rocket pack was developed and retrospectively fitted to the Mk 4 and Mk 5 seats, and then went into production as the Mk 6 and Mk 7 respectively. Over 1000 Mk 7s were produced for the _United States, and the British specification Mk 6 went into aircraft as diverse as, ironically, the Argentinian Air Force Pucara and Super Etendard. A Mk 8 seat was also designed for the BAC TSR-2 strike aircraft and featured a head restraining system. The Mk 8 seat died alongside the TSR-2.

Up to this time, the Martin-Baker designs were basically developments of the first Mk 1, and were becoming quite complicated. Thus, the Mk 9 was developed with simplified systems, incorporating a gas firing mechanism (rather than the mechanical cable type) operated by a single-seat pan handle. (It had been found that the time taken to reach for the top handle, especially in high ‘g’ situations, was often fatally lengthy. ) The Mk 9 seat was fitted to the Hawk and Jaguar.

The latest from the Martin-Baker factory is the Mk 10, which is an extensively modified version of the Mk 9; the main design difference is a combined personal/drogue parachute stored ih the headrest (replacing the separate headrest drogue/seat pan personal parachute system). A new steerable parachute design was also incorporated. A lightweight version of the seat, the 10L, is also available. The Mk 10 has design parameters for operation from 0 to 625 knots, with high sink rates at 0 feet above ground level to 50,000 feet. Inverted ejections are possible above 350 feet.

An ultralight Mk 11 seat is currently on the drawing board, aimed at sales with the light primary trainer aircraft, and weighs only 40 kg (90 lbs). Side-ejecting seats for helicopters are also possible in the future. But no matter what the aeroplane faces in the future, the Martin-Baker name will continue its association for many years to come.

The Americans

The Americans had also continued with ejection seat design, but never achieved the same degree of success as the British Martin-Baker company. A number of aircraft manufacturers designed systems tailored for a particular aircraft type. The A-4 Skyhawk, for example, has a Douglas system incorporating an unusual harness arrangement, where the harness is strapped on before entering the aircraft, and the pilot/harness combination is connected to the seat later. The biggest development in America was the escape capsule concept, which _was first designed for the F-111. The idea was to use the whole cockpit as an escape vehicle, pushed away from the aircraft by rocket motors. Flotation systems, chaff dispensers and life support systems were also incorporated. Although the capsule system itself is successful, the cost is prohibitive, and the F-111 was the only production aircraft to incorporate the system. The B-1 was also to use the system but reverted to the ejection seat on cost grounds.

The Douglas company still produces ejection seats and is also involved in lightweight seat development. The Minipac is one such design, aimed at the helicopter market. It is a gas-operated rocket system capable of multi-seat command firing, and incorporating a gyro system that alters the thrust line of the firing rocket to maintain a true trajectory. The system is upward firing, the main rotors being blown off in the escape sequence. The parachute is stored in the headrest and is deployed as the seat separates from the man (propelled by another rocket). For a two-crew ejection at 150 knots, the first man out will be in a full parachute 1. 83 seconds after firing, and the second man 0. 3 seconds later.

Another Douglas project is the Escapac series, designed for fixed-wing aircraft, and featuring high sink rate capabilities. Advanced Concept Ejection Seats (ACES) are Douglas’ other projects. These seats are normally fired by armrest-mounted handles and are fitted to such aircraft as the A-10 Thunderbolt, and F-15 Eagle.

The Stencel company is another major American producer, its main product, the SIIIS-3, is fitted to USMC AV-8A and Spanish Air Force ‘Matador’ Harriers, and the West German Air Force Alpha Jets (other Alpha Jets have the MB Mk 10). US Navy Skyhawks and Corsair cells are being retrofitted with a similar system. The SIIS-3 is a zero-zero seat, leared to 600 knots and up to 50,000 feet. Seat pan, face or armrest handles are dependent on customer requirements. The seat has different modes of operation for different flight envelopes and incorporates multi-redundant backup systems.

The ejection seat has been singularly responsible for saving thousands of lives and has become as commonplace as the Parachute. In the world of the defence industry, it is _ somehow quaint to find a product designed specifically to save lives rather than take them away, and perhaps deserves a special place in the history of aviation for more reasons than one.

Meteor Ejection . . .

On 29th August 1951, Warrant Officer Ron Guthne, a pilot with No. 77 Squadron, was flying in a section of eight RAAF Meteor F8 aircraft escorting American bombers on a mission high over North Korea. The section was attacked by North Korean MiG-15 fighters, and WOFF Guthrie’s aircraft, A-721, was hit by cannon fire. The pilot decided to eject at 38,300 feet and travel at Mach= 0. 84. He jettisoned his canopy and fired the seat with the face blind handle. Finding himself falling in the drogue-stabilised seat, WOFF Guthrie noticed his gloves were Missing, and he replaced the oxygen mask (which had also been blown off his face) and began to breathe the emergency oxygen. Looking down, he found himself falling towards the west coast of North Korea, so he decided to deploy his parachute as quickly as possible in the hope that he could control his descent and try to land in the sea where he had a better chance of being rescued by an American Air-Sea rescue plane. Braving the cold, he released the seat and pulled the ripcord at an altitude estimated at 35,000 feet. However, despite his efforts WOFF Guthrie came down (twenty-eight minutes after ejection) in enemy territory and was captured, remaining a POW until the end of the war. WOFF Guthrie was the first man to eject from an aircraft in combat, the fifth to make _ an emergency ejection, and the first Australian pilot to do so. His was also the highest-known bail-out at that time, and perhaps the longest-ever descent time. (Refer Australian Aviation, June 1979.)

Mirage Ejection

On 7th December 1964, soon after the introduction of the Mirage 111-0 into RAAF service, an RAF exchange pilot serving with the Aircraft Research and Development Unit (ARDU), Sqn. Ldr. I. Svensson, took off in the first 111-0, A3-1 test flight. The aircraft was to be tested over Avalon in Victoria, and during the flight, the aircraft went out of control with her incorrect spin recovery, and the pilot ejected at 7000 feet while in a steep rolling dive at a supersonic speed between 700 and 750 knots. The pilot used the face blind handle and punched out into the supersonic windblast, which removed his outer and inner helmet, separated the earpieces, removed his right gloves, watch, knee-pad, shredded his ‘g’ suit, and his Mae West. One of the leg restraining bowyangs was torn in half, and the other was never found. Despite the fact that the seat was operated outside its design parameters, it functioned perfectly. The pilot suffered a fractured right humerus (from leg fla1l1ng in the windblast), fractured right tibia and fibula (from either landing or leg retraction during the ejection phase), a fractured left femur (from the landing), minor abrasions (from opening shock, windblast, landing and oxygen mask separation), and shock and retrograde amnesia. But he was alive.

Canberra Ejection

On 14th March 1971, an RAAF Canberra, crewed by Wing Cdr. J. Downing (pilot and CO of 2 Squadron and Flt. Lt. A. Pinches (navigator), was flying a lone bombing mission to the far north of South Vietnam. The aircraft had just begun to turn for its run-in when it was hit by two Surface-Air Missiles. The pilot radioed a Mayday, and the two ejected. The navigator later recalled, ‘I sat in the seat to eject. Leaned back, pulled the blind and nothing happened. I had great difficulty in pulling it because of the air stream. I pulled it again as hard as I could and then I heard an explosion. ‘ The navigator had previously jettisoned his overhead hatch, and his seat fired out through the opening. ‘I was released from the seat and fell clear. Then I saw the pilot going down at a faster rate than me and he waved to indicate he was still all right. I saw the Canberra. Flames were coming from the wing and as it entered the cloud, pieces were starting to fall from the wing. ‘ The crew came down in Viet Cong territory, separated from each other by impassable terrain. The pilot had broken one knee on landing and bruised the other, and the navigator had fractured four vertebrae in the ejection and did not have full use of his arms. After one night in the jungle, the two were rescued by a USAF ‘dust off’ helicopter.

Skyhawk Ejection

On 21st October 1980, HMAS Melbourne was steaming some 200 kilometres southwest of Colombo. During the launch of one of its A4G Skyhawks, N13-154906 (885) piloted by Sub Lt. D. Saddens, the steam catapult launch system failed. As the aircraft shot off the end of the deck with insufficient airspeed. The pilot elected to eject. The ejection was successful, and the pilot was plucked out of the sea minutes later by a duty Wessex SAR helicopter. This loss, the second Skyhawk loss in that month whilst on task force tour, was also destined to be the last RAN A4G to be lost off HMAS Melbourne.

Royal Air Force Hawk Ejection

On the afternoon of 17th May 1980, the Royal Air Force ‘Red Arrows’ Aerobatic Team were carrying out a public display over the English seaside resort of Brighton. The show proceeded according to plan until the fourth ‘opposition’ passed by the ‘synchro pair’ aircraft. Unknown to the display duo, a yacht had motored into the path of No. 2 of the duo – who were authorised down to 35 feet altitude. As No. 2 made its pass, it collided with the top of the yacht’s 44 ft mast, damaging the aircraft’s flying control surfaces. The aircraft, a BAe Hawk T1 (XX 262), rolled uncontrollably to the right, and just three seconds after the collision, with the aircraft almost inverted and at less than 300 feet altitude, the pilot ejected. The aircraft crashed into the sea, and the pilot’s seat operated without fault (although at the limits of its design parameters) and he was rescued from the water suffering only minor injuries.