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Cessna Model 162 (Skycatcher) Spin Compliance/Safety Lessons Learned

Cessna Model 162 (Skycatcher) Spin Compliance/Safety Lessons Learned. C. Dale Bleakney (M) Cessna Engineering Flight Test. Introduction – What is an LSA?. ASTM 2245-xx: Max gross TO weight: 1320 lbs Min useful load - 430 lbs Vs min - 45 KCAS Vh max - 120 KCAS

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Cessna Model 162 (Skycatcher) Spin Compliance/Safety Lessons Learned

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  1. Cessna Model 162 (Skycatcher)Spin Compliance/Safety Lessons Learned C. Dale Bleakney (M) Cessna Engineering Flight Test

  2. Introduction – What is an LSA? • ASTM 2245-xx: • Max gross TO weight: 1320lbs • Min useful load - 430lbs • Vs min - 45KCAS • Vh max - 120KCAS • SE, fixed gear, fixed pitch prop

  3. Cessna LSA History Program Launch – Friday, January 13, 2006 Proof of Concept 1st Flight: Friday, October 13, 2006 Prototype 1st Flight: March 7, 2008 Wichita Built P1* 1st Flight: April 30, 2008 *P1 = Production No. 1

  4. Model 162: Final Configuration

  5. Instrument Panel

  6. Spin Program Overview In 1980, the US Supreme Court concluded that "Safe" is not the equivalent of "risk-free." LSA Spin Testing Goal: Safe, Thorough, Efficient ASTM 4.5.9: • ….(4) For the flaps-extended condition, the flaps may be retracted during recovery. 14 CFR 23.221 • ….. For the flaps-extended condition, the flaps may be retracted during the recovery but not before rotation has ceased. The rules are technically identical, Therefore: • Spin matrix was defined using FAA Advisory Circular 23-8B: • 352 spin conditions

  7. Safety Equipment/Process • First flight • Chute & Helmet • Chase aircraft w/video • Special Inspection • First Flight Readiness Review (FFRR) • Envelope expansion • Chute & Helmet • Chase aircraft • Stalls • Chute, Helmet, BRS (Aft cg) • Spins • BRS, Chute, Helmet • Chase aircraft w/video • Spin FFRR

  8. Spin Program Weather/Test Constraints**Before 1st Spin Event Weather Ceiling – MIN 10,000 feet Surface Winds – MAX 10 knots with 5 knot gusts (chute limits) Spins per sortie No MAX - BUTfatigue will be watched Crew Rest MAX - 5 flying days per week NOwork or flights on Sunday

  9. Spin Matrix and Buildup Program Before 1st Spin Event • Spin Matrix – Buildups (¼ , ½, 1 turn) • Fwd cg, idle power • Normal - flaps - up / down • Turning - flaps -up / down • Abused - flaps up / down • Repeat with power on - Buildup to MCP • Repeat at aft cg - Idle, then buildup to MCP

  10. Safety Systems Overview Crew Entry/Egress • Removable Door – 2 action • Procedure practiced before 1st flight Spin Chute (Options) • BRS Whole Airplane Chute –CHOSEN • Tail mounted airplane spin chute – NOT CHOSEN

  11. Spin Event No. 1 – September 18, 2008 • BUILDUP • Spins Successfully Completed: • Fwd cg Idle/MCP • Fwd cg MCP abused (ailerons with) • Event SPIN: MCP, ailerons against:3+ turns • KEY FACTS • 143 Successful spins completed • Key spin characteristics identified: • All spins were ASTM and 23.221 compliant • Redundant safety systems and safety discipline - ALL important

  12. Spin Event No. 1 - Lessons Learned • Safety Systems • BRS Spin Chute - Did not deploy • Rotation rates and spin attitude contributed to improper rocket trajectory and failure • Changed BRS parachute installation design • Door Jettison - Dual action door delayed bailout • Other • Buildups - Did not forecast event

  13. Risk Mitigation/Event analysis – Post Event No.1 • Internal Review • Flight Test • Project / Advanced Design • Outside Assistance • Former Cessna Test Pilots • Retired Cessna Aero / Advanced Design • BIHRLE • NTPS

  14. Post Spin Event No. 1BRS Design Changes OLDCanister Type Installation NEW Bed Mount Installation Parachute Actuation Handle • Soft Pack Design – No Canister • Parachute Bag - Oriented horizontally and near window • Rocket aft of parachute - Close proximity to window. No way it will catch on anything on the way out. • Cessna designed truss • Supports both parachute and rocket • Built in deflectors/guides Rocket

  15. Removable hinge pins Single Emergency Release Handle Post Event No. 1 - Door Release Changes

  16. Post-Event No. 1 - Bihrle Spin Tunnel testing • Power model updated • Predicted delayed spin recovery • Now matched event No. 1 spin • New vertical stabilizer w/ ventral • Spin tunnel data - No unrecoverable spin modes

  17. Safety Equipment/Process • Spin Briefings (Before and after 1st Event) • Include standard test card items • FTE monitors air-to-air frequency • Standard debrief, data review, and characteristics review • Missing elements(Lessons learned after 1st Event) • Telemetry • Ground crew at spin sight • Instrumentation • Control positions • Body angle of attack • Real-time pilot feedback

  18. Revised Spin Matrix – Post Event No. 1 Buildup redefined (look at aft cg earlier) • Idle –fwd cg, then aft cg • then, • MCP –fwd cg, then aft cg Note: 2000 rpm to MCP (100 rpm at a time) 28 to 33% MAC (1% at a time)

  19. Spin Videos – Mod 1 Configuration • Idle, Flaps Up, Right • Idle, Flaps 10, Left

  20. Risk Mitigation – Post Event No. 1 • SAME • Chase Aircraft • Spin Chute – BRS • Personal safety equipment • Brief and debrief • NEW • Fly the spin aero simulator before each new configuration • Go/No go as part of pre-flight brief • Post spin discussion of characteristics-to-simulator correlation • Detailed characteristics discussions with Flight, Aero, Safety • NO-GO decision is okay – Proceed with caution • Same as before but with increased emphasis • High definition video for post-spin analysis • Detailed flight reports to the Chief Pilot, Safety to independently assess positive and negative characteristics of each spin before we proceed.

  21. Spin/Stall Progress Chart We are now here

  22. Spin Event No. 2 - 3/19/2009 • COMM antenna damaged during BRS deployment • No communication with chase airplane • Rotation would not stop until engine shutdown • Pilot Door Jettison – Failed • (Door opened but would not jettison) • BRS saved the Pilot – Impact still substantial • (approx. 1600 fpm)

  23. Tail Change No. 2 Original design • Original tail (Mar 08) • Rev 1 tail (Sep 08) • 20% larger vertical tail • 10º less rudder sweep • Removed dorsal fin • Shielded rudder horn (directional stability) • Added ventral fin (not shown) • Rev 2 tail (V4) (Mar 09) • Increased rudder span • Ventral moved further aft • Maximum UP elevator changed from 30° to 22° Rev 1 Design Rev 2 (V4) Design

  24. Spin Compliance Completion Plan • Check Stability and Control/Stalls • Look for max AOA change: • Reduced max elevator travel (from 30° to 22°) • Power-on stall checked – lower AOA/better characteristics • Power-off stall speed checked - still ASTM compliant • Spin Compliance • New spin chute –Aft cg testingonly (due to aft truss/chute mount) • New spin matrix (with buildup) • Redo critical case spins without spin chute/with BRS

  25. Post Event No. 2 Safety/Flight Procedure Changes • Check Door Release, then re-attach before every spin flight • Maximum of 12spins per sortie. • Maximum of 2 sorties per day • 1 spin pilot – Pick up on subtle cues between spins • Early morning flights only – reduce pilot fatigue • Real time feedback from telemetry room on entry/recovery on every spin

  26. Spin Compliance Matrix (Post No. 2) • Original Spin Matrix • 352 Total Spins • Fwd then aft cg • Idle then MCP Power • Turning – over-the-top/under-the-bottom • Abused – ailerons with/against • Remaining untested spins (with spin chute) • 92 Total Spins • Aft cg – Normal • Aft cg – Turning • Aft cg – Abused (ailerons with, ailerons against, Idle/MCP) • Final Spins (without spin chute, with BRS) • Aft cg – Normal (IDLE), Normal (MCP) • MCP Abused (ailerons against) (Problem Spin)

  27. Spin Video – Final (Flaps 10, MCP, abused , Left , Ail Against) • With spin chute • Without spin chute

  28. Spin/Stall Progress Chart FINISHED 7/17/2009

  29. Spin Event Summary • September 18, 2008 (28% MAC) (Event No. 1) • BRS failure, Pilot bailed out • March 12, 2009 (30% MAC) (3 turn recovery) • Analyzed and thought to be caused by distributed ballast • March 19, 2009 (32% MAC) (Event No. 2) • (28%, 30%, 31% MAC successfully completed with new ballast configuration) • 32% MAC – recovery not seen after approx 3 turns • BRS deployed • Communication antenna lost • Jettison malfunctioned • Door release malfunctioned • Pilot rode airplane to ground • minor injuries to pilot • damage to airplane – most damage was after impact • July 17, 2009 (32% MAC) Spins successfully completed (with and without spin chute) • Stall and spin characteristics significantly improved • Final spin completed - 1 turn recovery. Meets ASTM and FAR 23

  30. Summary of Lessons Learned • Get recent spin practice in a similar airplane • Spin Tests should be done last - Final aero configuration • Look for excess flight control travels and limit them as necessary • Watch for subtle clues. Stall characteristics were a big clue. • NO two airplanes and NO two spins are identical (snowflake effect) • Safety systems mustbe robust. (Video) • TM data with experienced pilot feedback was very helpful • ¼ and ½ turn spin buildup did not predict 1 turn behavior However, it does acclimate and tune the pilot

  31. 162 Program - Interesting Statistics • Are you superstitious ??? • LSA Program go: Friday, Jan 13, 2006 • POC First flight: Friday, October 13, 2006 • First POC cross-country: AOPA, Palm Springs, CA • Flight 13, 1300 NM, took 13 hours • Spins • First Proto spin event, Spin 13, Thur, 9/18/08 • Second P1 spin event, Spin 13, Thur, 3/19/09 • Final P1 spin flight, Flight 169 (13 squared) • No more than 12 spins a day were done with the version 2 tail. • Don’t give the big guy a free shot – superstition or not

  32. Questions? Fun at Mach 0.162

  33. Post Event No. 1AerodynamicConfiguration Changes Original Proto configuration Post Event No. 1 configuration • Dorsal removed • Ventral added • Vertical stabilizer chord increased • Vertical stabilizer sweep angle decreased

  34. Spin Video – MCP Abused (Final –W/O Spin Chute) • Flaps 10, MCP, Left Spin, Ailerons Against – w/o chute

  35. Post Spin Event No. 1 - BRS Design Changes(Details on Next Slide) OLDCanister Type Installation NEW Soft pack Installation

  36. Bihrle Testing - Post-Event No. 2 • Bihrle Test Matrix • Baseline with flaps 10 • Baseline plus dorsal (Event configuration) • Three new vertical stabilizers (+20% area) • Baseline vertical + 5-in chord extension (V1) • New vertical with 10-deg sweep reduction (V4) • New vertical with zero sweep (V5) • Vented elevator • Horizontal stabilizer moved aft • Additional aileron deflections • Additional down elevator deflection • Conclusion • Selected V4 with/without ventral for simulation (see next slide)

  37. Post Event No. 1Aerodynamic Configuration Changes Vertical Stabilizer Changes V1 V4 Thorough!!

  38. Spin Video – Normal Spin • Rev 1 Configuration: Flaps Up, Idle, Left Spin

  39. Spin Video:Idle, Normal Spin Mod 1 Configuration: Flaps Up, Left Turn (Note Entry)

  40. Spin Event No. 2 - 3/19/2009 • Potential Causes • Change in perceived AOA at stall/spin entry –Too much elevator?? • BRS Spin Chute – Deployed but would not jettison • Rotation rate, spin attitude, inability to jettison BRS • High rotation rate caused risers to twist and increased friction in release pin attachment • Friction forces caused cable stretch – pilot unable to generate enough force to pull the release pin

  41. Stall/Spin Progress Chart Over 600 stalls completed before the first spin We are here

  42. Spin/Stall Progress Chart We are here

  43. Spin Video:MCP – Abused Spin • Mod 1 Configuration: Flaps Up, Left, MCP Ailerons Against

  44. FWD BRS Installation (Before 1st Event) Actuation Handle Safe

  45. Spin Program Schedule –Before 1st Spin Event • Efficient • Test Team (Pilot’s share spin sorties approx. 50/50) • Dale Bleakney – Project Pilot • Bob Newsome – Contract Pilot (former T-6A Test Pilot, and spin pilot) • Bob Rice – Assistance flying spins after first event • Andrew Thorson – FTE (in chase airplane) • Ahmed Mohamed – FTE (ground data analysis) • Sortie Generation Rate • 2 – 3 sorties per day • Spin Pilot/Chase Pilot alternate - Reduce fatigue

  46. 162 Configuration Change Summary September 2008 Original Configuration March 2009 Rev 1 Configuration Post Event No. 1 • Dorsal removed • Ventral fin added • Vertical stab chord increased • Vertical sweep angle decreased June 2009 Rev 2 Configuration Post Event No. 2 • Rudder extended • Ventral fin move aft • Ailerons geared (reduce adverse yaw) • Up elevator reduced from 30° to 22° (Significant)

  47. Aileron Change – Reduced Adverse Yaw Pre 3-19-2009aileronconfiguration 20° up/ 15° down Post 3-19-2009 aileron configuration 20° up/ 5° down (less adverse yaw)

  48. Summary – Lessons Learned - 2 • Safety • Spin chutes are proven technology.Design them in at the beginning • Spin tests should be donelastin a program after all aero data are gathered. Otherwise, you may end up repeating the spin tests. • Get recent spin practice in a similar airplane • NO two airplanes and NO two spins are identical (snowflake effect) • NO covenants with past programs.There may not be a correlation. • Watch for subtle clues. Stall characteristics were abigclue. • Reluctant to reduce up elevator due to stall speed impact - BIG • Safety systems MUST be robust. • TM data - essential. • Experienced pilot feedback from TM - invaluable.

  49. Model 162 Configurations Pre-September 2008 (Original) Post-September 2008 (Event No. 1) Increased vertical, added ventral Post-March 2009 (Event No. 2) (Final) Ventral Moved Aft, Rudder Extended Elevator UP Reduced, Aft cg limit Reduced, Ailerons re-geared

  50. Compliance Spin Test Status • Completed • Power Off – • Fwd/aft cg wings level • Fwd/Aft cg turning • Fwd/aft cg abused controls • Power On – • Fwd/aft cg wings level • Incomplete Conditions • Power On – Abused (Aft cg) • Power On – Turning (Aft cg)

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