An Online Resource for Flight Test Safety Planning

Example Maturation

Part 25 Stall Hazards

Organizations

• Six different organizations submitted THA information regarding stall flight testing – Bombardier (12) – Cessna (1) – FAA (5) – Gulfstream (6) – NTPS (26) – Tiger (2)

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Hazard Titles

• 19 different titles including: – Stalls – Stall Speed – Stall Speed (Ice Shapes Installed) – Stalling Period – Stall Characteristics – Stall Characteristics with Delayed Turn (On Ice Shapes) – Wings level stall – Turning flight and accelerated turning stalls – Position Light System Installation – Demonstration of Misinstalled Thrust Reverser – Rudder Available Determination - A/C with 40% increased PCUs installed

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FAR Paragraphs

• Seven different Part 25 paragraphs originally had stall related hazards, but the matured data applies to: – 25.103, Stalling Speed – 25.201, Stall Demonstration – 25.203, Stall Characteristics – 25.207, Stall Warning

NTPS

Maneuver Name

• 14 different maneuver names – Stall speed determination – Stall characteristics determination – Stall – Stalls conducted with power on and off – Full stall (straight) – Full stall (turning) – Full stall (accelerated turning) – Straight stalls – contaminated leading edge – TCAS testing – Windshear Testing – Windmill airstart – APU flight test – Rudder available determination with 40%-increased PCUs installed – Simulated rejected takeoffs

NTPS

Identified Hazard

• Most varied field in submitted data • The focus of maturing effort, along with minimizing procedures for the agreed-upon hazard identified • As an example: – Original • “ There is a risk of stall/departure from controlled flight when increasing angle-of-attack at low airspeeds. ” – Became: • “ Loss of control ” • For Part 25 stall tests, we ended up with just six hazards

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Matured Hazard Titles

• After submitted by NTPS and reviewed by the FAA and NASA, six hazards were identified with respect to Part 25 stall testing 1. Loss of control 2. Stall/spin chute fails to deploy 3. Stall/spin chute fails to jettison when commanded 4. Departing runway surface (During ground test of stall spin chute) 5. Recovery chute uncommanded deployment 6. Loss of operating engine(s )

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Loss of Control Causes

• Many contributions of test safety planning did not include the “ causes ” – just the hazards and mitigations • Of the ones submitted, the following were included in the matured THA ’ s 1. Unpredicted aerodynamic response.

2. Stick Pusher fails to prevent aircraft from reaching aerodynamic stall.

3. Improper control inputs.

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Mitigations

• Literally hundreds of varied mitigations were matured into just twelve – • The matured mitigations include: 1. Do stall testing in a buildup approach : a. from least risk to highest risk i. forward cg, mid cg, aft cg ii. Power off before power on iii. Wings level before turning iv. 1 kt /sec before 3 kt /sec b. terminate buildup if FAR limits on bank angle are exceeded at any point of the buildup

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Mitigations (continued)

2. Establish minimum altitudes for: a. entry, b. recovery initiation, c. recovery chute deployment and d. manual bailout.

3. Perform pre-flight checks of stall warning and stick pusher, as applicable.

4. Anti-spin chute must be installed, functional and armed. Perform pre-flight and pre-maneuver checks of chute as applicable.

5. Minimum crew onboard.

6. Emergency Egress system must be installed and armed. Perform pre-flight and pre-maneuver checks of egress system as applicable.

NTPS

Mitigations (continued)

7. Crew to wear helmets and parachutes .

8. Surface winds must be less than xx kts (parachute dependent).

9. No aggravated input stalls . All stalls will be ball centered.

10. No asymmetric power stalls.

11. If departing controlled flight retard throttles to idle and centralize controls .

12. Do not add power during recovery until airspeed is increasing above 1.2 Vs.

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Database Now Open to the Public

http:// pbma.nasa.gov/ftsdb / Look for “ Test Hazard Database ”

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http:// pbma.nasa.gov/ftsdb /

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FAR Reference Search

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Record Field Search

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Keyword Search

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Results of FAR Reference Search

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In Conclusion

• Database status – Civil Part 25 THA ’ s “ complete ” – Civil Part 23/27/29/31 under construction – Military & research THA ’ s - TBD • The matured THA database is NOT an auto-safety planning device – The matured hazards, causes and mitigations are necessarily generic – Your test will have unique problems and will require unique solutions – The THA database can be an excellent starting point • Lessons learned should be shared – We don ’ t have enough time to learn every lesson firsthand

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