Aeromedical aircraft on descent undershot VOR crossing altitude.

Attributes
ACN	124337
Time
Date	198910
Day	Wed
Local Time Of Day	0001 To 0600
Place
Locale Reference	atc facility : sau
State Reference	CA
Altitude	msl bound lower : 5000 msl bound upper : 6000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : oak
Operator	common carrier : air taxi
Make Model Name	Small Transport
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 70 flight time total : 1800 flight time type : 1100
ASRS Report	124337
Person 2
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : undershoot altitude deviation : crossing restriction not met non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Cleared to cross 5 DME northwest of sau VORTAC at 5000'. From 35 DME northwest at 15,000' miscalculation of winds aloft, ground speed and descent rate, crossed fix 1000' above assigned altitude. Both crew members had been aware nearly 24 hours before incident and were exhausted after initial call for flight at XA00. VMC conditions existed and no other traffic was observed in our area visually or by radio. Being on call for 24 hour period allows for legal 10 hour rest period, but does not really allow sufficient rest for crews.

Original NASA ASRS Text

Title: AEROMEDICAL ACFT ON DESCENT UNDERSHOT VOR CROSSING ALT.

Narrative: CLRED TO CROSS 5 DME NW OF SAU VORTAC AT 5000'. FROM 35 DME NW AT 15,000' MISCALCULATION OF WINDS ALOFT, GND SPEED AND DSCNT RATE, CROSSED FIX 1000' ABOVE ASSIGNED ALT. BOTH CREW MEMBERS HAD BEEN AWARE NEARLY 24 HRS BEFORE INCIDENT AND WERE EXHAUSTED AFTER INITIAL CALL FOR FLT AT XA00. VMC CONDITIONS EXISTED AND NO OTHER TFC WAS OBSERVED IN OUR AREA VISUALLY OR BY RADIO. BEING ON CALL FOR 24 HR PERIOD ALLOWS FOR LEGAL 10 HR REST PERIOD, BUT DOES NOT REALLY ALLOW SUFFICIENT REST FOR CREWS.

Data retrieved from NASA's ASRS site as of August 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.