Narrative:

The PIC filed the IFR flight plan at 13000 ft MSL without consulting me. Previous experience with pointing out far discrepancies led me to believe there was nothing to be gained by pointing out the conflict of operating at 13000 ft without oxygen. About 1 hour into the flight, the PIC requested a rerouting to a latitude/longitude somewhat off the direct, filed route. ATC cleared us via the rerte. I was not concerned, likely due to developing hypoxia, and neglected to check the sectional chart for terrain clearance. During the flight we lost radio contact, due to location, then later contacted a new controller, as assigned before we lost contact with the previous controller. The new controller asked where we were, and we gave our position relative to yakutat. He somewhat incredulously asked, 'you have not been proceeding direct to destination?' the PIC replied we had been cleared via the new latitude/longitude, then direct to destination.' the controller said he did not have that, stated we were in a mountainous area, and we needed to climb immediately to FL180. At this point we broke out into good VMC, saw there were no mountains close by, although there were clouds off to our left. We canceled IFR and descended below 10000 ft. After a few mins in lower altitude, I became concerned enough to check the sectional for terrain information. I saw that we had flown perhaps within 10 mi of a high mountain off to our left, and had not known it. I do not believe we came within 2000 ft of any terrain, but it was good fortune only, not good planning. In my opinion the willingness of the PIC to fly at 13000 ft MSL unpressurized, without oxygen available, my reluctance to assert myself, and the ensuing hypoxia, led us into a situation where we did not know there was higher terrain near our route of flight. (My reluctance to assert myself was connected with the fact that the PIC was my chief pilot, and I was in the right seat to receive familiarization with the operation.) the failure of ATC to note our requested route carried us into higher MEA than they could authority/authorized, coupled with a breakdown of communication within ATC such that the ensuing controller did not know of the rerte, contributed to the occurrence.

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Original NASA ASRS Text

Title: FLT CREW OF UNPRESSURIZED MEL ACFT WITHOUT SUPPLEMENTAL OXYGEN OPERATE IFR FLT AT 13000 FT MSL IN MOUNTAINOUS TERRAIN NEAR YAK. IMPAIRED MENTAL CAPACITIES RESULTED IN EXPOSURE TO CFIT.

Narrative: THE PIC FILED THE IFR FLT PLAN AT 13000 FT MSL WITHOUT CONSULTING ME. PREVIOUS EXPERIENCE WITH POINTING OUT FAR DISCREPANCIES LED ME TO BELIEVE THERE WAS NOTHING TO BE GAINED BY POINTING OUT THE CONFLICT OF OPERATING AT 13000 FT WITHOUT OXYGEN. ABOUT 1 HR INTO THE FLT, THE PIC REQUESTED A REROUTING TO A LATITUDE/LONGITUDE SOMEWHAT OFF THE DIRECT, FILED RTE. ATC CLRED US VIA THE RERTE. I WAS NOT CONCERNED, LIKELY DUE TO DEVELOPING HYPOXIA, AND NEGLECTED TO CHK THE SECTIONAL CHART FOR TERRAIN CLRNC. DURING THE FLT WE LOST RADIO CONTACT, DUE TO LOCATION, THEN LATER CONTACTED A NEW CTLR, AS ASSIGNED BEFORE WE LOST CONTACT WITH THE PREVIOUS CTLR. THE NEW CTLR ASKED WHERE WE WERE, AND WE GAVE OUR POS RELATIVE TO YAKUTAT. HE SOMEWHAT INCREDULOUSLY ASKED, 'YOU HAVE NOT BEEN PROCEEDING DIRECT TO DEST?' THE PIC REPLIED WE HAD BEEN CLRED VIA THE NEW LATITUDE/LONGITUDE, THEN DIRECT TO DEST.' THE CTLR SAID HE DID NOT HAVE THAT, STATED WE WERE IN A MOUNTAINOUS AREA, AND WE NEEDED TO CLB IMMEDIATELY TO FL180. AT THIS POINT WE BROKE OUT INTO GOOD VMC, SAW THERE WERE NO MOUNTAINS CLOSE BY, ALTHOUGH THERE WERE CLOUDS OFF TO OUR L. WE CANCELED IFR AND DSNDED BELOW 10000 FT. AFTER A FEW MINS IN LOWER ALT, I BECAME CONCERNED ENOUGH TO CHK THE SECTIONAL FOR TERRAIN INFO. I SAW THAT WE HAD FLOWN PERHAPS WITHIN 10 MI OF A HIGH MOUNTAIN OFF TO OUR L, AND HAD NOT KNOWN IT. I DO NOT BELIEVE WE CAME WITHIN 2000 FT OF ANY TERRAIN, BUT IT WAS GOOD FORTUNE ONLY, NOT GOOD PLANNING. IN MY OPINION THE WILLINGNESS OF THE PIC TO FLY AT 13000 FT MSL UNPRESSURIZED, WITHOUT OXYGEN AVAILABLE, MY RELUCTANCE TO ASSERT MYSELF, AND THE ENSUING HYPOXIA, LED US INTO A SIT WHERE WE DID NOT KNOW THERE WAS HIGHER TERRAIN NEAR OUR RTE OF FLT. (MY RELUCTANCE TO ASSERT MYSELF WAS CONNECTED WITH THE FACT THAT THE PIC WAS MY CHIEF PLT, AND I WAS IN THE R SEAT TO RECEIVE FAMILIARIZATION WITH THE OP.) THE FAILURE OF ATC TO NOTE OUR REQUESTED RTE CARRIED US INTO HIGHER MEA THAN THEY COULD AUTH, COUPLED WITH A BREAKDOWN OF COM WITHIN ATC SUCH THAT THE ENSUING CTLR DID NOT KNOW OF THE RERTE, CONTRIBUTED TO THE OCCURRENCE.

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.