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Pilot of small aircraft unpressurized aircraft experienced hypoxia at high altitude due to a malfunctioning oxygen system resulting in excursion from assigned altitude and course.
| Attributes | |
| ACN | 232084 |
| Time | |
| Date | 199301 |
| Day | Sat |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : pdx |
| State Reference | OR |
| Altitude | msl bound lower : 21000 msl bound upper : 21000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zse tower : dfw |
| Operator | general aviation : instructional |
| Make Model Name | Small Aircraft, Low Wing, 1 Eng, Retractable Gear |
| Flight Phase | climbout : intermediate altitude |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : single pilot |
| Qualification | pilot : instrument pilot : commercial |
| Experience | flight time last 90 days : 25 flight time total : 400 flight time type : 15 |
| ASRS Report | 232084 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Events | |
| Anomaly | aircraft equipment problem : critical altitude deviation : excursion from assigned altitude other anomaly other anomaly other other spatial deviation |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | flight crew : regained aircraft control flight crew : overcame equipment problem flight crew : exited adverse environment |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | Pilot Deviation other |
Narrative:
Flying a non pressurized, turbocharged aircraft in climb to FL210 with factory installed oxygen system (filled for flight by equipment manufacturer) and mask. Developed intense hypoxia. Preflight showing oxygen flow. Symptoms of buzzing in head, tingling of fingers and feet as well as confusion. Immediately asked for lower altitude, but had difficulty maintaining course and altitude prior to request. Also had difficulty plotting RNAV route and entering data into equipment (single pilot). Of note, I was monitoring blood oxygen saturation as this was only my 2ND flight higher than 18000 ft, and it quickly dropped to 70 percent. Further for unclr reasons (? Hypoxia) mp dropped to 15 inches just after starting descent because of hypoxia and malfunctioning oxygen. Alternate air had no effect and I suspected turbocharger malfunction. An emergency was declared and radar vectors to the closest airport were obtained, landing without incident. I am certainly glad I chose a VFR day and monitored my blood oxygen saturation while getting early experience in higher altitude operations. Just because one notes flowing oxygen on preflight does not insure that hypoxia will not occur. We are still investigating the problem.
Original NASA ASRS Text
Title: PLT OF SMA UNPRESSURIZED ACFT EXPERIENCED HYPOXIA AT HIGH ALT DUE TO A MALFUNCTIONING OXYGEN SYS RESULTING IN EXCURSION FROM ASSIGNED ALT AND COURSE.
Narrative: FLYING A NON PRESSURIZED, TURBOCHARGED ACFT IN CLB TO FL210 WITH FACTORY INSTALLED OXYGEN SYS (FILLED FOR FLT BY EQUIP MANUFACTURER) AND MASK. DEVELOPED INTENSE HYPOXIA. PREFLT SHOWING OXYGEN FLOW. SYMPTOMS OF BUZZING IN HEAD, TINGLING OF FINGERS AND FEET AS WELL AS CONFUSION. IMMEDIATELY ASKED FOR LOWER ALT, BUT HAD DIFFICULTY MAINTAINING COURSE AND ALT PRIOR TO REQUEST. ALSO HAD DIFFICULTY PLOTTING RNAV RTE AND ENTERING DATA INTO EQUIP (SINGLE PLT). OF NOTE, I WAS MONITORING BLOOD OXYGEN SATURATION AS THIS WAS ONLY MY 2ND FLT HIGHER THAN 18000 FT, AND IT QUICKLY DROPPED TO 70 PERCENT. FURTHER FOR UNCLR REASONS (? HYPOXIA) MP DROPPED TO 15 INCHES JUST AFTER STARTING DSCNT BECAUSE OF HYPOXIA AND MALFUNCTIONING OXYGEN. ALTERNATE AIR HAD NO EFFECT AND I SUSPECTED TURBOCHARGER MALFUNCTION. AN EMER WAS DECLARED AND RADAR VECTORS TO THE CLOSEST ARPT WERE OBTAINED, LNDG WITHOUT INCIDENT. I AM CERTAINLY GLAD I CHOSE A VFR DAY AND MONITORED MY BLOOD OXYGEN SATURATION WHILE GETTING EARLY EXPERIENCE IN HIGHER ALT OPS. JUST BECAUSE ONE NOTES FLOWING OXYGEN ON PREFLT DOES NOT INSURE THAT HYPOXIA WILL NOT OCCUR. WE ARE STILL INVESTIGATING THE PROB.
Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.