<< >> NASA ASRS Report 666262, July 2005

BE35 pilot attributes airspace violation and impaired mental ability to hypoxia resulting from flight at 12500 ft.

Attributes
ACN	666262
Time
Date	200507
Place
Locale Reference	airport : las.airport
State Reference	NV
Altitude	msl single value : 12500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla.artcc
Operator	general aviation : personal
Make Model Name	Bonanza 35
Operating Under FAR Part	Part 91
Flight Phase	descent : intermediate altitude
Flight Plan	None
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : cfi pilot : commercial pilot : instrument
Experience	flight time last 90 days : 40 flight time total : 13800 flight time type : 1800
ASRS Report	666262
Person 2
Affiliation	government : faa
Function	controller : radar
Events
Anomaly	airspace violation : entry non adherence : far other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : became reoriented flight crew : exited adverse environment
Supplementary
Problem Areas	Aircraft Environmental Factor Flight Crew Human Performance
Primary Problem	Environmental Factor
Air Traffic Incident	Pilot Deviation

Narrative:

In retrospect; it is clear to me that I encountered an advanced case of hypoxia in my VFR descent. I had been cruising for about 4 hours with flight following at 12500 ft; and the flight at that altitude had been progressing uneventfully. When I announced to center that I would commence a VFR descent; I was handed off to another sector. This is when things went awry. I think I may have heard wrong or selected a wrong frequency; but my attempts at contact went nowhere; and somehow I was unable to return to my previous controller. This seems incredible for a pilot with my level of experience; but; while flying the airplane was no problem; handling even the most simple mental tasks became almost impossible. As a result; I entered class B airspace without a clearance. I am 73 yrs old; but am in excellent health; have never smoked; and do not drink alcohol. But I realize now that; obviously; prolonged flight; even at the legal altitude of 12500 ft; can have a very detrimental effect on one's mental capacity. Also in retrospect; I remember that it was rather warm at altitude. This would have raised the density altitude even further. I received a real education; and one of the first things I will invest in will be portable oxygen equipment.

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Original NASA ASRS Text

Title: BE35 PLT ATTRIBUTES AIRSPACE VIOLATION AND IMPAIRED MENTAL ABILITY TO HYPOXIA RESULTING FROM FLT AT 12500 FT.

Narrative: IN RETROSPECT; IT IS CLR TO ME THAT I ENCOUNTERED AN ADVANCED CASE OF HYPOXIA IN MY VFR DSCNT. I HAD BEEN CRUISING FOR ABOUT 4 HRS WITH FLT FOLLOWING AT 12500 FT; AND THE FLT AT THAT ALT HAD BEEN PROGRESSING UNEVENTFULLY. WHEN I ANNOUNCED TO CTR THAT I WOULD COMMENCE A VFR DSCNT; I WAS HANDED OFF TO ANOTHER SECTOR. THIS IS WHEN THINGS WENT AWRY. I THINK I MAY HAVE HEARD WRONG OR SELECTED A WRONG FREQ; BUT MY ATTEMPTS AT CONTACT WENT NOWHERE; AND SOMEHOW I WAS UNABLE TO RETURN TO MY PREVIOUS CTLR. THIS SEEMS INCREDIBLE FOR A PLT WITH MY LEVEL OF EXPERIENCE; BUT; WHILE FLYING THE AIRPLANE WAS NO PROB; HANDLING EVEN THE MOST SIMPLE MENTAL TASKS BECAME ALMOST IMPOSSIBLE. AS A RESULT; I ENTERED CLASS B AIRSPACE WITHOUT A CLRNC. I AM 73 YRS OLD; BUT AM IN EXCELLENT HEALTH; HAVE NEVER SMOKED; AND DO NOT DRINK ALCOHOL. BUT I REALIZE NOW THAT; OBVIOUSLY; PROLONGED FLT; EVEN AT THE LEGAL ALT OF 12500 FT; CAN HAVE A VERY DETRIMENTAL EFFECT ON ONE'S MENTAL CAPACITY. ALSO IN RETROSPECT; I REMEMBER THAT IT WAS RATHER WARM AT ALT. THIS WOULD HAVE RAISED THE DENSITY ALT EVEN FURTHER. I RECEIVED A REAL EDUCATION; AND ONE OF THE FIRST THINGS I WILL INVEST IN WILL BE PORTABLE OXYGEN EQUIP.

Data retrieved from NASA's ASRS site as of January 2009 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.