Medium large transport flight crew has altitude deviation on descent approach.

Attributes
ACN	295678
Time
Date	199502
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : mco
State Reference	FL
Altitude	msl bound lower : 8700 msl bound upper : 9000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : mco
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : instrument pilot : atp
Experience	flight time last 90 days : 186 flight time total : 6040 flight time type : 926
ASRS Report	295678
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other

Narrative:

This report is really about fatigue rather than an altitude deviation. This was my 7TH consecutive day of duty, my 2ND day of flying. I was quite tired when coming on duty at XA45. During the flight, everything went okay. On the descent we were given a crossing restr at leese intersection. The DME portion of the mco VOR was out causing some confusion in identing the leese intersection. After switching to orlando approach, we were given a descent clearance to 9000 ft. Both the first officer and myself were able to see the airport and I asked the first officer to tell approach. At this time I was primed for a clearance for a visual approach. After the first officer advised approach that we had the field insight we were given a vector for the downwind. I thought we were also cleared for a visual approach. As we descended through 8700 ft the altimeter alerter sounded. I stopped the descent and initiated a climb. I directed the first officer to ask for a further descent clearance. We were given clearance to 8000 ft. There was no traffic conflict. I feel that my judgement was impaired by fatigue. I also feel that one is unable to accurately decide when one is too tired to fly. I know I was unable on this day to tell. If some kind of tests could be developed to help pilots identify fatigue and the resulting performance degradation I think safety could be greatly enhanced.

Original NASA ASRS Text

Title: MLG FLC HAS ALTDEV ON DSCNT APCH.

Narrative: THIS RPT IS REALLY ABOUT FATIGUE RATHER THAN AN ALTDEV. THIS WAS MY 7TH CONSECUTIVE DAY OF DUTY, MY 2ND DAY OF FLYING. I WAS QUITE TIRED WHEN COMING ON DUTY AT XA45. DURING THE FLT, EVERYTHING WENT OKAY. ON THE DSCNT WE WERE GIVEN A XING RESTR AT LEESE INTXN. THE DME PORTION OF THE MCO VOR WAS OUT CAUSING SOME CONFUSION IN IDENTING THE LEESE INTXN. AFTER SWITCHING TO ORLANDO APCH, WE WERE GIVEN A DSCNT CLRNC TO 9000 FT. BOTH THE FO AND MYSELF WERE ABLE TO SEE THE ARPT AND I ASKED THE FO TO TELL APCH. AT THIS TIME I WAS PRIMED FOR A CLRNC FOR A VISUAL APCH. AFTER THE FO ADVISED APCH THAT WE HAD THE FIELD INSIGHT WE WERE GIVEN A VECTOR FOR THE DOWNWIND. I THOUGHT WE WERE ALSO CLRED FOR A VISUAL APCH. AS WE DSNDED THROUGH 8700 FT THE ALTIMETER ALERTER SOUNDED. I STOPPED THE DSCNT AND INITIATED A CLB. I DIRECTED THE FO TO ASK FOR A FURTHER DSCNT CLRNC. WE WERE GIVEN CLRNC TO 8000 FT. THERE WAS NO TFC CONFLICT. I FEEL THAT MY JUDGEMENT WAS IMPAIRED BY FATIGUE. I ALSO FEEL THAT ONE IS UNABLE TO ACCURATELY DECIDE WHEN ONE IS TOO TIRED TO FLY. I KNOW I WAS UNABLE ON THIS DAY TO TELL. IF SOME KIND OF TESTS COULD BE DEVELOPED TO HELP PLTS IDENT FATIGUE AND THE RESULTING PERFORMANCE DEGRADATION I THINK SAFETY COULD BE GREATLY ENHANCED.

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.