A cpr twin jet experiences an altitude excursion when the autoplt trips off without the crew's knowl...

Attributes
ACN	430950
Time
Date	199903
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : ptk.airport
State Reference	MI
Altitude	msl bound lower : 24700 msl bound upper : 25000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zob.artcc
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	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : corporate
Function	flight crew : first officer
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 120 flight time total : 4825 flight time type : 120
ASRS Report	430950
Person 2
Affiliation	company : corporate
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	aircraft equipment : altitude alert other flight crewa other flight crewb
Resolutory Action	flight crew : became reoriented flight crew : returned to original clearance
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

Descent below assigned flight level as advised by ATC. Autoplt kicked off and crew was alerted by altitude select chime. Returned to appropriate flight level and no incident occurred. At the time autoplt kicked off, crew was performing descent checklist and did not notice autoplt in the off position. Better situational awareness in future would avoid such incidents.

Original NASA ASRS Text

Title: A CPR TWIN JET EXPERIENCES AN ALT EXCURSION WHEN THE AUTOPLT TRIPS OFF WITHOUT THE CREW'S KNOWLEDGE.

Narrative: DSCNT BELOW ASSIGNED FLT LEVEL AS ADVISED BY ATC. AUTOPLT KICKED OFF AND CREW WAS ALERTED BY ALT SELECT CHIME. RETURNED TO APPROPRIATE FLT LEVEL AND NO INCIDENT OCCURRED. AT THE TIME AUTOPLT KICKED OFF, CREW WAS PERFORMING DSCNT CHKLIST AND DID NOT NOTICE AUTOPLT IN THE OFF POS. BETTER SITUATIONAL AWARENESS IN FUTURE WOULD AVOID SUCH INCIDENTS.

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.

A cpr twin jet experiences an altitude excursion when the autoplt trips off without the crew's knowledge.