Altitude deviation altitude excursion.

Attributes
ACN	296296
Time
Date	199502
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : h19
State Reference	MO
Altitude	msl bound lower : 21000 msl bound upper : 21800
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zkc
Operator	general aviation : corporate
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	climbout : intermediate altitude cruise other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : atp
Experience	flight time last 90 days : 100 flight time total : 4400 flight time type : 300
ASRS Report	296296
Person 2
Affiliation	Other
Function	observation : passenger
Qualification	other other : other
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : overshoot non adherence : clearance
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : became reoriented other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

I had taken off from H19 and was leveling at FL210 assigned, by use of the autoplt. The aircraft pitched over normally and started to accelerate. I then took a moment to listen to a passenger complain about the cabin temperature. The controller came on and reminded me we were now at FL218. Upon examination I found that the autoplt had kicked itself off. I have subsequently noticed that the trim on the aircraft is slowing and may not keep up with a level off at lower flight levels. I would recommend monitoring any trends in autoplt performance and to not risk relying on it for any function without watching closely. On the other hand if you must watch very close a single pilot loses the advantage an autoplt provides. We will have it checked.

Original NASA ASRS Text

Title: ALTDEV ALT EXCURSION.

Narrative: I HAD TAKEN OFF FROM H19 AND WAS LEVELING AT FL210 ASSIGNED, BY USE OF THE AUTOPLT. THE ACFT PITCHED OVER NORMALLY AND STARTED TO ACCELERATE. I THEN TOOK A MOMENT TO LISTEN TO A PAX COMPLAIN ABOUT THE CABIN TEMP. THE CTLR CAME ON AND REMINDED ME WE WERE NOW AT FL218. UPON EXAMINATION I FOUND THAT THE AUTOPLT HAD KICKED ITSELF OFF. I HAVE SUBSEQUENTLY NOTICED THAT THE TRIM ON THE ACFT IS SLOWING AND MAY NOT KEEP UP WITH A LEVEL OFF AT LOWER FLT LEVELS. I WOULD RECOMMEND MONITORING ANY TRENDS IN AUTOPLT PERFORMANCE AND TO NOT RISK RELYING ON IT FOR ANY FUNCTION WITHOUT WATCHING CLOSELY. ON THE OTHER HAND IF YOU MUST WATCH VERY CLOSE A SINGLE PLT LOSES THE ADVANTAGE AN AUTOPLT PROVIDES. WE WILL HAVE IT CHKED.

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.