1. Mount Cook Airline Safety Investigations & Education in an Airline Nathan McGraw 05 June 2010

2. Mount Cook Operational Safety2 Overview Mount Cook Airline - our approach to safety Tail icing investigation

3. Mount Cook Operational Safety3 Who are we? Part of the Air NZ Group Wholly owned subsidiary Independent AOC 11 x ATR 72-500 2,300 sectors per month 10 scheduled destinations

4. Mount Cook Operational Safety4 Our Approach to Safety We don’t rank safety: Safety is critical Use SMS principals (formal SMS in development) Proactive approach (don’t wait for an incident) Investigate events that go well Safety education is essential

5. Mount Cook Operational Safety5 Our Approach to Safety Operational Safety (not Flight Safety or OSH) Previously an ‘investigation office’ only Op Safety team  Two pilots (F/Os)  Two cabin crewmembers All current line crewmembers (minimum 50% line flying) Safety focus (no fingers in other pies)

6. Mount Cook Operational Safety6 Our Approach to Safety Cabin crew are an essential part of the team  Many investigations have a cabin crew aspect  Separate area of expertise  Non-technical approach  Non-management contact for line cabin crewmembers  Line cabin crewmembers have a voice (better buy-in)

7. Mount Cook Operational Safety7 Our Approach to Safety Safety Advisors, not Investigators  Both pilots have training & examining backgrounds  Both pilots are FOs and have been Captains previously  Qualified military test pilot and instructor  Trained investigators  RABQSA accredited auditor  HF training (USC, ATSB)

8. Mount Cook Operational Safety8 Our Approach to Safety Essential Qualities of a Safety Advisor  Integrity  Objectivity  Moral courage  Respected by crewmembers and management  High personal standards (sets an example)  Infectious attitude towards safety (generative approach)

9. Mount Cook Operational Safety9 Our Approach to Safety Ratio of work 30% monitoring (processing data, reports) 20% investigations 60% safety liaison & education ____ 110% (we work very hard) Focus on education improves credibility and buy-in  credibility =  report quality & quantity

10. Mount Cook Operational Safety10 Safety Reports Investigation Positive Education Trust / Buy-in Maintaining Credibility

11. Mount Cook Operational Safety11 Our Approach to Safety Safety Reports – our morning newspaper  All about trust (hard to earn, shattered in an instant)  Absolute avoidance of punitive action  De-identification, even when not requested  Responsible to the regulator for notification; but  Greater responsibility to our fellow crewmembers  Integrity (we do what we say we’ll do)

12. Mount Cook Operational Safety12 Our Approach to Safety Safety Investigations - how can we do this better?  Evidence-based approach  Huge HF emphasis  Lots of tests for ‘reasonableness’  Substitution tests to identify systemic factors  Absolute avoidance of punitive content

13. Mount Cook Operational Safety13 Our Approach to Safety Safety Education – Give people the tools to be safe!  Op Safety Report: weekly report to management  Safety Snapshot: monthly occurrence bulletin  Aoraki Safety: biannual magazine  Op Safety website: library, links, resources  Classroom: HF module during annual CRM courses  All positive material – no preachy statements

14. Mount Cook Operational Safety14 Our Approach to Safety Traditional Safety Office  Get summonsed when you’ve had an incident  Only produces investigation reports  Punishment for naughty pilots Message: Safety Office is a negative place Our Op Safety office  Positive place (even during investigations)  Churns out positive safety material (learning emphasis)  Try to make safety interesting, enjoyable, and accessible

15. Mount Cook Operational Safety15 Recent Investigations TCAS TA at Queenstown GNSS Database Validity Engine failure after takeoff DG fumes in-flight Severe turbulence (yes Peter, it’s coming) Tail icing events

16. Mount Cook Operational Safety16 Tail Icing Events Important  Not suggesting that the ATR is unsafe in icing conditions  ATR has produced comprehensive & detailed information for operators and pilots  ATR icing procedures are robust and appropriate  Investigation is applicable to all aircraft types  Only significant points covered in this presentation

17. Mount Cook Operational Safety17 Tail Icing Events NZ Climate  Polar Maritime (cold, moist flow)  Airframe icing at altitude (especially for turboprops)  NZ pilots generally knowledgeable about airframe icing  Icing all year – both events happened in late summer

18. Mount Cook Operational Safety18 Tail Icing Events First Event  Freezing rain in climb between FL160 and FL170 (Marlborough Sounds)  Significant reduction in rate-of-climb to <200 fpm  Ice detection system alert  Immediate cruise descent to FL150  Air was 5 °C warmer and all visible ice melted quickly  Flight continued at FL150 with no visible ice accretion

19. Mount Cook Operational Safety19 Tail Icing Events First Event  After 15 minutes at FL150, loud bang and severe vibration from tail area  Vibration lasted for over 30 seconds but then ceased  Pilots disconnected AP and checked for controllability – all normal  Experienced crew – never encountered vibrations so strong  Suspected ice but diverted to Palmerston North due severity of vibration  Thorough maintenance inspection – no defects or abnormalities

20. Mount Cook Operational Safety20 Tail Icing Events Second Event  Ice accretion earlier in flight  “Significant icing remained on the IEP”  Cruised in VMC  IMC on descent but VMC at 7,000 ft  All visible ice melted by 4,000 ft

21. Mount Cook Operational Safety21 Tail Icing Events Second Event  No visible ice and +11 °C on the ground  All ice protection systems turned off (as per SOP)  Pilots planned for and briefed a non-icing landing  ‘Fish tailing’ on final approach  Unstable in pitch and yaw – difficult to stabilise and trim  Landed uneventfully

22. Mount Cook Operational Safety22 Tail Icing Events Second Event  After disembarking, pilots noted significant ice on stabiliser  Ice on pneumatic boots (protected section),  Estimated 150mm forward of leading edge

23. Mount Cook Operational Safety23 Tail Icing Events Analysis  Considered defects with flight controls, trims, autopilot, ice protection  Review of maintenance records – no defects or discrepancies  Functional test of pneumatic boots – no defects  Tail icing most likely contributing factor

24. Mount Cook Operational Safety24 Tail Icing Events NASA Tail Icing Research (early 1990s)  Tail icing historically poorly understood  Icing accidents between 1950 & 1980 often misdiagnosed as wing stalls  Tail surfaces accrete ice earlier and faster than wings (sharper leading edge)  Propeller aircraft are more susceptible (particularly turboprops)  Possible to have ice on stabiliser with no other ice on airframe

25. Mount Cook Operational Safety25 Tail Icing Events Stabiliser on turboprop aircraft often sits in prop wash Higher velocity = lower temperature Prop wash air can be up to 5 °C cooler than ambient Tail can be in icing conditions, even if the rest of the aircraft isn’t! Prop wash at higher angles-of-attack (for illustrative purposes only).

26. Mount Cook Operational Safety26 Tail Icing Events Design features which support tail icing (NASA)  Un-powered and aerodynamically balanced elevators  Pnuematic de-icing boots in lieu of heated leading edges  Horizontal stabilisers with sharp leading edges  Large flap deflections (big change of relative airflow over tail) These features are applicable to a lot of turboprops Tail ice can be 3 – 6 times thicker than on the wings

27. Mount Cook Operational Safety27 Tail Icing Events Findings – First Event  No maintenance defects or anomalies  Loud bang was likely tail ice breaking free in warmer air at FL150  Vibration was likely airflow disruption over elevator due to ice breaking free unevenly  Gave the crew a real fright – a very unusual icing event

28. Mount Cook Operational Safety28 Tail Icing Events Findings – Second Event  No maintenance defects or anomalies  Pilots followed SOPs exactly (passes substitution test)  Residual ice on the tail was very unusual  Aerodynamic instability on approach likely caused by tail icing  Pilots reported symptoms similar to an impending tailplane stall

29. Mount Cook Operational Safety29 Tail Icing Events Symptoms of impending tailplane stalls (NASA)  Lightening of controls (particularly forward motion)  Difficulty trimming  Onset of pilot-induced oscillations due to change of control balance  Control buffeting (but not the airframe)

30. Mount Cook Operational Safety30 Tail Icing Events Severe Icing QRH Checklist  Includes significant protections against tailplane stall (reduced flap landing)  Pilots used it only when in defined severe icing  Once clear of severe icing, pilots would resume normal ops and land with full flap (breaking the checklist)  Tail icing is possible without being in defined severe icing  Recommended that checklist be used whenever tail icing is suspected (regardless of whether icing was severe or not)

31. Mount Cook Operational Safety31 Tail Icing Events Recommendations  Training module for tail icing  Icing exercise in simulator that results in a reduced flap landing  Use severe icing checklist (including reduced flap landing) if tail icing is suspected, even if airframe is visibly clear of all ice

32. Mount Cook Operational Safety32 Tail Icing Events Results  Good support from ATR during investigation  Great company support, particularly Flight Ops and Training  Enthusiastic uptake from training team  Pilots now routinely report landing with reduced flaps after significant ice encounters  Investigation resulted in positive training and tangible results

33. Thanks!