Narrative:

I filed an IFR flight plan from ida direct to bzn with en route altitude of 15000 MEA. After passing through 12000 ft I put on the oxygen mask and activated the system. However, after about 5-10 mins of use the regulator malfunctioned or there was some type of restriction in the delivery line as the oxygen supply stopped. I elected to continue the flight at 15000 to bzn because the forecast WX conditions at ida called for rapidly deteriorating conditions. En route flight time was approximately 2 hours with estimated 1 1/2 hours above 12500 ft. The entire flight was in IMC. Upon reaching bzn, I found great difficulty and confusion in performing the tasks required to execute the ILS and VOR approachs. After 3 unsuccessful approachs, ZLC diverted me to btm for landing in VFR conditions. Prior to reaching btm a small private field became available and the flight was terminated with a VFR landing at this field. (Jeffco at whitehall). In retrospect, although I train students using the bzn approachs and know them well, I am sure my performance, judgement and decision making ability was degraded by hypoxia and fatigue.

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Original NASA ASRS Text

Title: AN SMA PLT SUFFERING FROM HYPOXIA FAILS TO SUCCESSFULLY COMPLETE 3 IAP ILS VOR APCHS. GETS FLT ASSIST IN DIVERSION TO ALT ARPT.

Narrative: I FILED AN IFR FLT PLAN FROM IDA DIRECT TO BZN WITH ENRTE ALT OF 15000 MEA. AFTER PASSING THROUGH 12000 FT I PUT ON THE OXYGEN MASK AND ACTIVATED THE SYS. HOWEVER, AFTER ABOUT 5-10 MINS OF USE THE REGULATOR MALFUNCTIONED OR THERE WAS SOME TYPE OF RESTRICTION IN THE DELIVERY LINE AS THE OXYGEN SUPPLY STOPPED. I ELECTED TO CONTINUE THE FLT AT 15000 TO BZN BECAUSE THE FORECAST WX CONDITIONS AT IDA CALLED FOR RAPIDLY DETERIORATING CONDITIONS. ENRTE FLT TIME WAS APPROX 2 HRS WITH ESTIMATED 1 1/2 HRS ABOVE 12500 FT. THE ENTIRE FLT WAS IN IMC. UPON REACHING BZN, I FOUND GREAT DIFFICULTY AND CONFUSION IN PERFORMING THE TASKS REQUIRED TO EXECUTE THE ILS AND VOR APCHS. AFTER 3 UNSUCCESSFUL APCHS, ZLC DIVERTED ME TO BTM FOR LNDG IN VFR CONDITIONS. PRIOR TO REACHING BTM A SMALL PVT FIELD BECAME AVAILABLE AND THE FLT WAS TERMINATED WITH A VFR LNDG AT THIS FIELD. (JEFFCO AT WHITEHALL). IN RETROSPECT, ALTHOUGH I TRAIN STUDENTS USING THE BZN APCHS AND KNOW THEM WELL, I AM SURE MY PERFORMANCE, JUDGEMENT AND DECISION MAKING ABILITY WAS DEGRADED BY HYPOXIA AND FATIGUE.

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.