Noncompliance with clearance.

Attributes
ACN	295945
Time
Date	199502
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : lhs
State Reference	CA
Altitude	msl bound lower : 9000 msl bound upper : 13000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : okc
Operator	general aviation : corporate
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Route In Use	enroute airway : zla
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : cfi pilot : commercial
Experience	flight time last 90 days : 250 flight time total : 4000 flight time type : 300
ASRS Report	295945
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	altitude deviation : crossing restriction not met altitude deviation : undershoot non adherence : clearance
Independent Detector	other controllera
Resolutory Action	none taken : insufficient time
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I requested a lower altitude. A few min later I believed I heard the controller tell me that I could descend to 5000 ft after crossing 5 mi south of lake hughes VOR. I repeated clearance. He came back with 9000 ft. I repeated down to 9000 ft after crossing 5 mi south of lake hughes. At 5 mi south of lake hughes the controller said I guess you aren't going to make it to 9000 ft. I was given a phone number to call. I had a little trouble hearing the phone number and it was repeated back in correctly by me twice. I got it right the third time. I called and spoke with a supervisor and he cautioned me to question ATC whenever I was unsure of a clearance. He let it go at that after listening to my explanation. However, I told him I repeated the crossing restr twice. I was using oxygen for 1.25 hours prior to event. I now realize that the oxygen was causing sinus problems and slightly blocked my ability to hear clearly. I rarely fly at altitudes requiring oxygen therefore do not use it much. I did not experience sinus problems prior to this event.

Original NASA ASRS Text

Title: NONCOMPLIANCE WITH CLRNC.

Narrative: I REQUESTED A LOWER ALT. A FEW MIN LATER I BELIEVED I HEARD THE CTLR TELL ME THAT I COULD DSND TO 5000 FT AFTER XING 5 MI S OF LAKE HUGHES VOR. I REPEATED CLRNC. HE CAME BACK WITH 9000 FT. I REPEATED DOWN TO 9000 FT AFTER XING 5 MI S OF LAKE HUGHES. AT 5 MI S OF LAKE HUGHES THE CTLR SAID I GUESS YOU AREN'T GOING TO MAKE IT TO 9000 FT. I WAS GIVEN A PHONE NUMBER TO CALL. I HAD A LITTLE TROUBLE HEARING THE PHONE NUMBER AND IT WAS REPEATED BACK IN CORRECTLY BY ME TWICE. I GOT IT RIGHT THE THIRD TIME. I CALLED AND SPOKE WITH A SUPVR AND HE CAUTIONED ME TO QUESTION ATC WHENEVER I WAS UNSURE OF A CLRNC. HE LET IT GO AT THAT AFTER LISTENING TO MY EXPLANATION. HOWEVER, I TOLD HIM I REPEATED THE XING RESTR TWICE. I WAS USING OXYGEN FOR 1.25 HRS PRIOR TO EVENT. I NOW REALIZE THAT THE OXYGEN WAS CAUSING SINUS PROBS AND SLIGHTLY BLOCKED MY ABILITY TO HEAR CLRLY. I RARELY FLY AT ALTS REQUIRING OXYGEN THEREFORE DO NOT USE IT MUCH. I DID NOT EXPERIENCE SINUS PROBS PRIOR TO THIS EVENT.

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.