Trade Study Analysis of two different methods for helicopter cockpit emergency egress

1. Trade Study Analysis of two different methods for helicopter cockpit emergency egress Margaret Peterson EMIS 7305 Spring 2011

2. Content 1. Background 2. Ground Rules and Assumptions. 3. Analysis 4. Summary

3. Background • Trade study was conducted to examine two different Helicopter Emergency System • Due to the limited amount of space available in the cockpit area, maintenance performed on the crew seat are often done outside of the aircraft. • The design impact on the maintenance task time of the cockpit crew seat.

4. Background • The cockpit emergency egress system provides an escape path for the cockpit crew member in an event of an emergency landing or ditching under water. • Method 1: Pyrotechnic Egress System • Activation initiators • Initiation blocks • Pyrotechnic or detonation cord • Energy transfer lines • Requires Certified Pyro technician to removed • Military Application • Boeing Apache • Bell/Boeing V-22 • Sikorsky Comanche

5. Background Sample Pyrotechnic Egress System

6. Background • Method 2: Mechanical Release System • Latch • Release mechanism (handle) • Links • Pins • Attachment hardware • Easy to remove; turn the handle and push the window out of the airframe • Military Application • Bell 214 Kiowa • Sikorsky Blackhawk

7. Background Sample Mechanical Release system

8. Background • Sample Crew Seat – BAE S7000 Model

9. Ground Rules/Assumptions • Non-complaint TPMs are the weight requirement and the Mean Time to Repair (MTTR) requirement • In order to go to CDR, the program must be compliant with all TPMs • Crew seat is subjected to inspection every 500 flight hours • Crew Seat MTBF=1450 hours • Mechanical Release System MTBF=4500 hours • Pyrotechnic Egress System MTBF=7500 hours • Fly 200 hours every year • A sub-system is considered to be the crew seat and emergency egress system

10. Analysis Weight Breakdown Comparison

11. Analysis • Task Analysis Model was created for each of following maintenance task: • Crew Seat Removal Task Timeline with Mechanical Release System • Crew Seat Installation Task Timeline with Mechanical Release System • Pyrotechnic Removal Task Timeline • Pyrotechnic Installation Task Timeline • Cockpit Side Window Removal Task Timeline • Cockpit Side Window Installation Task Timeline • Seat Removal Task Timeline out the side window • Seat Installation Task Timeline out the side window • Seat Removal Task Timeline out the opening between the cockpit and cabin • Seat Installation Task Timeline out the opening between the cockpit and cabin

12. Analysis Task Analysis Model for removing seat with mechanical release system

13. Analysis Crew Seat/Mechanical release system MTTR calculations

14. Analysis Crew Seat/Pyrotechnic release system MTTR calculations

15. Analysis Crew Seat/ out the opening between the cockpit and cabin MTTR calculations

16. Summary Weight Breakdown Comparison Crew Seat Task Time Comparison Summary

17. Summary MTTR Comparison

18. Summary • Pyrotechnic egress system is 21 lbs lighter than the Mechanical release system • A helicopter configuration with the mechanical release system has the lowest MTTR for the crew seat. • MTTR = 0.91 hrs • A helicopter configuration with the pyrotechnic egress system has the highest MTTR for the crew seat. • MTTR = 3.90 hrs • Based on our assumptions, any inspection and/or maintenance action of the crew seat may not be needed for at least 2.5 years • Recommended that the program management go with the pyrotechnic egress design because of the immediate weight savings.