Beechcraft baron pilot reported diverting to a nearby suitable airport after an engine that had been...

Attributes
ACN	1354332
Time
Date	201605
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Baron 55/Cochise
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	None
Flight Plan	VFR
Component
Aircraft Component	Propeller Autofeather System
Person 1
Function	Pilot Flying Trainee
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Engineer
Experience	Flight Crew Last 90 Days 240 Flight Crew Total 11000 Flight Crew Type 119
Events
Anomaly	Aircraft Equipment Problem Critical Airspace Violation All Types

Narrative:

Was flying as pilot-under-instruction on routine training refresher flight. Part of the practice was the controlled shutdown; feather; and re-start of each engine. When attempting to unfeather the right engine; it initially would not unfeather. We remained in the practice area offshore; but became distracted by the procedure and it appeared that we were close to the lateral limits of [the] class C airspace. Upon recognizing this; we immediately headed east to avoid. We continued to monitor approach frequency; but did not check in with them; as our intention was to remain clear of their airspace; as we continued to troubleshoot the malfunction; as we proceeded south offshore during this process. After all inflight procedures had become exhausted; it became apparent that the propeller could not be moved out of feather; and thus tower at the nearest airport [was advised]. We then proceeded to land without incident. Post-flight examination showed that the internal rubber bladder of the unfeathering accumulator had failed internally; without warning or indication; thus preventing the propeller from unfeathering in flight. Although we did not want to 'bother' busy approach with our (then) non-emergent troubleshooting; perhaps it would have been better to call them when approaching the lateral limits of their airspace.

Original NASA ASRS Text

Title: Beechcraft Baron pilot reported diverting to a nearby suitable airport after an engine that had been intentionally feathered for training would not unfeather.

Narrative: Was flying as pilot-under-instruction on routine training refresher flight. Part of the practice was the controlled shutdown; feather; and re-start of each engine. When attempting to unfeather the right engine; it initially would not unfeather. We remained in the practice area offshore; but became distracted by the procedure and it appeared that we were close to the lateral limits of [the] Class C airspace. Upon recognizing this; we immediately headed east to avoid. We continued to monitor Approach frequency; but did not check in with them; as our intention was to remain clear of their airspace; as we continued to troubleshoot the malfunction; as we proceeded south offshore during this process. After all inflight procedures had become exhausted; it became apparent that the propeller could not be moved out of FEATHER; and thus Tower at the nearest airport [was advised]. We then proceeded to land without incident. Post-flight examination showed that the internal rubber bladder of the unfeathering accumulator had failed internally; without warning or indication; thus preventing the propeller from unfeathering in flight. Although we did not want to 'bother' busy Approach with our (then) non-emergent troubleshooting; perhaps it would have been better to call them when approaching the lateral limits of their airspace.

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.

Beechcraft baron pilot reported diverting to a nearby suitable airport after an engine that had been intentionally feathered for training would not unfeather.