LIFE ORIENTED FLIGHT TRAINING (LOFT) AND NORMOBARIC HYPOXIA IN F/A-18C HORNET SIMULATOR Major Tuomo Leino, MD, PhD Pilot Physician Air Force Command Finland
Disclosure Information 85 th Annual Scientific Meeting Tuomo Leino, MD, PhD I have the following financial relationships to disclose: - Employee of: Air Force Command Finland I will not discuss off-label use and/or investigational use in my presentation.
Introduction Hypoxia training is used to only demonstrate individual symptoms of hypoxia to pilots In Finland, hypoxia training in hypobaric chamber was given until 2007 without refreshment training In-flight hypoxia incident reports on F/A-18C Hornet OBOGS malfunction, loss of cabin pressure, mask or tube leak CO toxication, hyperventilation, tension neck caused dizziness Normobaric hypoxia training in F/A-18C WTSAT and Hawk simulator given since 2008 OBOGS maintenance after 450fh and ECS turbine change after 1,200fh in Finland (originally on-condition equipment)
Methods F/A-18C WTSAT simulator was used 57 pilots were trained in 2013 LOFT mission included 2 visual identification (VID) set-ups at high altitude as lead aircraft of 2-ship formation SARNEC password given before flight, not allowed to write it down In each set-up, different oxygen concentrations were used to demonstrate TUC difference Pressurized air in initial stage of each set-up until 2NM before VID 8% or 6% oxygen in nitrogen was suddenly turned on (normobaric hypoxia) Pilots continued mission until they recognized hypoxia symptoms Emergency procedures (EP) and return to base (RTB) 3min after EP execution, empty emergency oxygen bottle was simulated Technical malfunctions (HYD1B and later R engine near-stall) occurred in flight MECH-ON, if R engine shutdown ejection ILS Y 04L approach to Helsinki airport in minimum weather conditions
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Results O2 saturation during hypoxia recognition varied between 88% and 58% (median 75%) 30% of pilots did not remember SARNEC password after flight (indicating short-duration memory impairment) Cognitive impairment was also noted during EP execution and ILS approach Ejection after MECH-ON (two pilots shut down R engine after stall) Reported adverse effects 12 h after hypoxia training: Tiredness and fatigue (n=8) Headache (n=3) Dizziness (n=3) Hot flush in face Tingling
Lessons learned When pilots recognize hypoxia symptoms, hypoxia is already affecting situational awareness and decisionmaking Some pilots continued VID at high altitude after GREEN RING - PULL Do NOT modify immediate action EP Emergency procedures 100% emergency oxygen on is highest priority Emergency descent should be started in 20 nose-down attitude CFIT risk in steep inverted dive Flight performance improves after 45s with 100% oxygen Dive angle can be changed, especially in cabin pressure malfunction (DCS risk) Priorities: 1. aviate 2. navigate 3. communicate Some pilots do not recall what happened under hypoxia Simulator data recording and debriefing
Lessons learned Transponder code 7700 ATC priority during descent to low altitude (MSA or VFR, not FL100) Routine in executing oxygen EP under hypoxia is crucial Pilots understand that TUC (Time of Useful Conciousness) at FL500 is only 9 secs Hypoxia refreshment training in F/A-18C simulator has to be repeated every 3 years Hypoxia, although treated with 100% emergency oxygen, affects performance during RTB Radar trail formation as number 1 to monitor airspeed and altitude and handle radio communications Prepare for O2 hose disconnection after emergency bottle is empty after 3min No mask-open flying (radio communications and neck injury risk during ejection) Fuel calculation to alternative airport at low altitude GCI controller assistance (to maintain separation to traffic) and OPSO consultation
Lessons learned New oxygen monitor (ECP-590) change to F/A-18C will be delayed Usually no MASTER CAUTION and OBOGS DEG warning in real situations Need for better oxygen monitoring system If hypoxia symptoms persist after landing, although treated in-flight with 100% emergency oxygen, consider altitude DCS and hyperbaric oxygen therapy
Lessons learned Cognitive impairment after hypoxia may last for several hours although EP are executed without delay 12h grounding after normobaric hypoxia training has been in effect in Finland since 2008 LOFT approch to hypoxia simulator training offers decision-making training for military pilots
tuomo.leino@mil.fi