Incorporating the SJU-17A Naval Aircrew Common Ejection Seat in the EA-6B Aircraft

This research investigated the feasibility of incorporating the Martin Baker Aircraft Company (MBA) SJU-17A Naval Aircrew Common Ejection Seat (NACES) and an electronic command eject sequencing system in the Northrop-Grumman EA-6B Prowler aircraft. The EA-6B is a four seat tactical aircraft derived from the A-6 Intruder airframe and flown solely by the U. S. Navy and Marine Corps. The mission of the EA-6B is electronic warfare (EW), providing suppression of enemy air defenses (SEAD) by the use of electronic noise jamming and the employment of the AGM-88 High Speed Anti-Radiation Missile (HARM). The current ejection system in the EA-6B uses the MBA GRUEA-7 ejection seat combined with a gas sequencing command ejection system, and has a 1.2 second delay before the pilot’s ejection sequence begins. This time is excessive in a crashing aircraft and the loss of 3 pilot lives can be attributed to this delay. Out-of-envelope ejections have led to the loss of 8 additional ECMO lives. These two factors have caused the EA-6B ejection system to make the top-ten list of required change priorities of the Operational Advisory Group (OAG) of EA-6B community. The EA-6B will be the only aircraft in the U. S. Navy still using the GRU-7 series of ejection seats when the F-14A/B model Tomcats are retired by 2008, placing a strain on the maintenance and logistics systems to keep the seats in safe working condition. A discussion of the GRUEA-7 ejection seat requirements compared to the SJU-17A NACES was used to determine feasibility of incorporating this new ejection seat in the EA-6B. The basis of the research was the review of ejection seat publications, EA-6B aircraft literature, interviews conducted with the enlisted personnel that maintain v the ejection seats, and the experience of the author as a Naval Flight Officer (NFO) in both the EA-6B and the FA-18F. This thesis concluded that the SJU-17A NACES is more capable than the GRUEA-7 ejection seat and feasibly adaptable to the EA-6B airframe as both a stand-alone seat and part of an electronic command ejection system. The recommendations of this thesis were: 1. Replace the MBA GRUEA-7 ejection seat with the MBA SJU-17A NACES in the EA-6B aircraft. 2. Replace the gas sequencing ejection system with an electronic command ejection sequencing system in the EA-6B aircraft, and investigate the possibility of ejecting more than 1 aircrew at a time after performing a structural analysis of the floorboards and airframe to make sure the added reaction forces will be supported. 3. Replace the 21 foot diameter main parachute in the SJU-17A NACES with a 28 foot diameter main parachute for incorporation into the EA-6B aircraft after investigating the additional opening shock imparted to the occupant by the larger parachute throughout the expected EA-6B flight regime and the impact on the five SJU-17A NACES modes of operation.