Masters Theses

Date of Award

5-2003

Degree Type

Thesis

Degree Name

Master of Science

Major

Aviation Systems

Major Professor

Dr. Frank G. Collins

Committee Members

Dr. Uwe P. Solies, Mr. Richard J. Ranaudo

Abstract

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.

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