Light transport cpr jet did not make assigned crossing restr on descent.

Attributes
ACN	421570
Time
Date	199811
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : jot
State Reference	IL
Altitude	msl bound lower : 15000 msl bound upper : 17500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : apa
Operator	general aviation : corporate
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Navigation In Use	Other
Flight Phase	descent other
Route In Use	arrival other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : cfi pilot : commercial
Experience	flight time last 90 days : 140 flight time total : 14000 flight time type : 1200
ASRS Report	421570
Person 2
Affiliation	government : faa
Function	controller : radar
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : undershoot altitude deviation : crossing restriction not met non adherence : far other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : insufficient time
Consequence	Other
Supplementary
Air Traffic Incident	Pilot Deviation

Narrative:

ATC requested I cross 65 mi west of jot at 15000 ft. I set the automated FMC VNAV unit to manage the descent. The GPS portion was acting up but functional and unit was using vors for accuracy. The unit failed to capture the descent. I crossed my restr point at 17500 ft (not 15000 ft) as requested. I feel that since the unit did not show any flag that it would function properly -- even though in remarks the GPS portion was OTS. The unit is being sent to the manufacturer for chkout. ATC did not remark that I had missed my crossing restr.

Original NASA ASRS Text

Title: LTT CPR JET DID NOT MAKE ASSIGNED XING RESTR ON DSCNT.

Narrative: ATC REQUESTED I CROSS 65 MI W OF JOT AT 15000 FT. I SET THE AUTOMATED FMC VNAV UNIT TO MANAGE THE DSCNT. THE GPS PORTION WAS ACTING UP BUT FUNCTIONAL AND UNIT WAS USING VORS FOR ACCURACY. THE UNIT FAILED TO CAPTURE THE DSCNT. I CROSSED MY RESTR POINT AT 17500 FT (NOT 15000 FT) AS REQUESTED. I FEEL THAT SINCE THE UNIT DID NOT SHOW ANY FLAG THAT IT WOULD FUNCTION PROPERLY -- EVEN THOUGH IN REMARKS THE GPS PORTION WAS OTS. THE UNIT IS BEING SENT TO THE MANUFACTURER FOR CHKOUT. ATC DID NOT REMARK THAT I HAD MISSED MY XING RESTR.

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.