A seneca ii pilot reported his right throttle stuck at altitude; presumably due to freezing of moist...

Narrative:

The aircraft spent the previous 2 nights on the ramp at the airport; under relatively heavy rain. Almost immediately after taking off; I was in solid IMC. During the climb; I picked up some moderate mixed ice. The deicing and anti-icing systems were all working fine. After reaching 11;000 ft; ATC (I'm pretty sure it was approach at the time) asked me to quickly descend to 10;000 ft for traffic. I tried pulling both throttles back; but the right throttle stuck; as if it were frozen in place. I advised ATC; who seemed (understandably) bewildered. ATC asked if I was declaring an emergency. I replied 'no.' I managed to reduce the mixture slightly on the right engine and the manifold pressure dropped enough to easily descend to 10;000 ft. After leveling at 10;000 ft for a few minutes; the throttle came unstuck with some strong pressure. It worked find for the rest of the flight. On 2 subsequent flights that day; the same thing happened on the climbout. The right throttle froze/stuck and I couldn't reduce power after the climb to a cruise setting. Each time it took less pressure and less time to 'un-stick' the throttle; indicating to me that there was moisture in the throttle control line that hadn't evaporated. I'm having an a&P/ia look at the throttle linkage this week to make sure it's sealed and lubricated properly.

Original NASA ASRS Text

Title: A Seneca II pilot reported his right throttle stuck at altitude; presumably due to freezing of moisture in the linkage. The pilot was able to free the throttle with high pressure applied to the lever. The aircraft had sat on an open ramp in heavy rain the two previous nights.

Narrative: The aircraft spent the previous 2 nights on the ramp at the airport; under relatively heavy rain. Almost immediately after taking off; I was in solid IMC. During the climb; I picked up some moderate mixed ice. The deicing and anti-icing systems were all working fine. After reaching 11;000 FT; ATC (I'm pretty sure it was Approach at the time) asked me to quickly descend to 10;000 FT for traffic. I tried pulling both throttles back; but the right throttle stuck; as if it were frozen in place. I advised ATC; who seemed (understandably) bewildered. ATC asked if I was declaring an emergency. I replied 'no.' I managed to reduce the mixture slightly on the right engine and the manifold pressure dropped enough to easily descend to 10;000 FT. After leveling at 10;000 FT for a few minutes; the throttle came unstuck with some strong pressure. It worked find for the rest of the flight. On 2 subsequent flights that day; the same thing happened on the climbout. The right throttle froze/stuck and I couldn't reduce power after the climb to a cruise setting. Each time it took less pressure and less time to 'un-stick' the throttle; indicating to me that there was moisture in the throttle control line that hadn't evaporated. I'm having an A&P/IA look at the throttle linkage this week to make sure it's sealed and lubricated properly.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	823025
Time
Date	200902
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Make Model Name	PA-34-200 Seneca I
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Throttle/Power Level
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Private
Experience	Flight Crew Last 90 Days 15 Flight Crew Total 2000 Flight Crew Type 290
Events
Anomaly	Aircraft Equipment Problem Less Severe

A seneca ii pilot reported his right throttle stuck at altitude; presumably due to freezing of moisture in the linkage. The pilot was able to free the throttle with high pressure applied to the lever. The aircraft had sat on an open ramp in heavy rain the two previous nights.