Altitude bust in descent procedure.

Attributes
ACN	252374
Time
Date	199309
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : bdr
State Reference	CT
Altitude	msl bound lower : 7600 msl bound upper : 8000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : cmh
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Flight Phase	descent other
Route In Use	enroute airway : v487
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 100 flight time total : 3500 flight time type : 1500
ASRS Report	252374
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot non adherence : clearance other anomaly other
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : became reoriented flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Instructed to descend from 10000 ft to 8000 ft. I set 8000 ft in altitude alerter. I became distracted and noticed the aircraft descending through 7600 ft at the same time that approach called to question our altitude. The captain, who was PF, immediately returned the airplane to 8000 ft. Contributing factors are excessive duty time and minimal rest requirements which are allowed by far 135. My company uses computerized schedules to aggressively utilize pilots to the legal maximum, which results in a much higher level of fatigue than envisioned possible by the framers of the regulation. A pilot may remove himself from duty, of course, but this increases one's financial problems, as you will lose pay time if you do so. As an example, 9- leg, 14-hour days are not uncommon, nor are 14-hour days with 3 hours of flying, often with 8 hours rest in between. Fatigue was a large contributing factor in this occurrence.

Original NASA ASRS Text

Title: ALT BUST IN DSCNT PROC.

Narrative: INSTRUCTED TO DSND FROM 10000 FT TO 8000 FT. I SET 8000 FT IN ALT ALERTER. I BECAME DISTRACTED AND NOTICED THE ACFT DSNDING THROUGH 7600 FT AT THE SAME TIME THAT APCH CALLED TO QUESTION OUR ALT. THE CAPT, WHO WAS PF, IMMEDIATELY RETURNED THE AIRPLANE TO 8000 FT. CONTRIBUTING FACTORS ARE EXCESSIVE DUTY TIME AND MINIMAL REST REQUIREMENTS WHICH ARE ALLOWED BY FAR 135. MY COMPANY USES COMPUTERIZED SCHEDULES TO AGGRESSIVELY UTILIZE PLTS TO THE LEGAL MAX, WHICH RESULTS IN A MUCH HIGHER LEVEL OF FATIGUE THAN ENVISIONED POSSIBLE BY THE FRAMERS OF THE REG. A PLT MAY REMOVE HIMSELF FROM DUTY, OF COURSE, BUT THIS INCREASES ONE'S FINANCIAL PROBS, AS YOU WILL LOSE PAY TIME IF YOU DO SO. AS AN EXAMPLE, 9- LEG, 14-HR DAYS ARE NOT UNCOMMON, NOR ARE 14-HR DAYS WITH 3 HRS OF FLYING, OFTEN WITH 8 HRS REST IN BTWN. FATIGUE WAS A LARGE CONTRIBUTING FACTOR IN THIS OCCURRENCE.

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.