The pilot of a PA31 was surprised by an unusual attitude while on an IFR flight plan when the autopi...

Attributes
ACN	1213222
Time
Date	201410
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	PA-31 Navajo/Chieftan/Mojave/T1040
Operating Under FAR Part	Part 135
Flight Phase	Descent
Route In Use	Direct
Flight Plan	IFR
Component
Aircraft Component	Autopilot
Person 1
Function	Single Pilot Pilot Flying
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Instructor
Experience	Flight Crew Total 5500
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Deviation - Track / Heading All Types

Narrative:

I was flying from home at FL220. I was given a pilot descend to 10;000 feet. I was on the autopilot and I began the descent with a couple of down pitch trims on the trim wheel. I turned on the overhead dome light and opened my flight bag to get my ipad out. Soon after; the controller told me to contact center. My eyes came back over to the control wheel and instruments. At that point; I saw that the attitude indicator showed an extreme downward unusual attitude. I immediately brought my power to idle and I believe started initiating the recovery at that point. I did not understand how it happened because the autopilot had been on and there was no aural tone that went off saying it had disconnected. The next thing that happened was that I began using the co-pilot attitude indicator to complete the recovery. When I was recovered; I was at least 90 degrees off course pointed to the east and at a rough altitude of 17;000 feet. I canceled IFR shortly after that. I believe that the auto pilot began a descending right turn without me knowing. I also believe that the combination of having the dome light on; and turning toward a darker section of terrain led to not catching the autopilot going off course. It was my first full blown unusual attitude recovery. It was a very large eye opener. More vigilance to autopilot monitoring may have caught it a slight bit sooner.

Original NASA ASRS Text

Title: The pilot of a PA31 was surprised by an unusual attitude while on an IFR flight plan when the autopilot became unexpectedly disconnected.

Narrative: I was flying from home at FL220. I was given a pilot descend to 10;000 feet. I was on the autopilot and I began the descent with a couple of down pitch trims on the trim wheel. I turned on the overhead dome light and opened my flight bag to get my iPad out. Soon after; the controller told me to contact Center. My eyes came back over to the control wheel and instruments. At that point; I saw that the attitude indicator showed an extreme downward unusual attitude. I immediately brought my power to idle and I believe started initiating the recovery at that point. I did not understand how it happened because the autopilot had been on and there was no aural tone that went off saying it had disconnected. The next thing that happened was that I began using the co-pilot attitude indicator to complete the recovery. When I was recovered; I was at least 90 degrees off course pointed to the east and at a rough altitude of 17;000 feet. I canceled IFR shortly after that. I believe that the auto pilot began a descending right turn without me knowing. I also believe that the combination of having the dome light on; and turning toward a darker section of terrain led to not catching the autopilot going off course. It was my first full blown unusual attitude recovery. It was a very large eye opener. More vigilance to autopilot monitoring may have caught it a slight bit sooner.

Data retrieved from NASA's ASRS site 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.