A Q400 flight crew encountered recurring resistance to rudder inputs during the descent.

Narrative:

While leveling at 12;000ft and slowing to 250K; we received permission to speed up; so the first officer applied power and needed to also apply right rudder to compensate for the yaw caused by the increase in power. I was talking to company during this time when I felt the aircraft yaw hard to the right. I asked; 'what happened?' the first officer replied; 'the rudder was stuck.' we then needed to keep descending and slowing and with power pulled back we needed left rudder to compensate for the power change. The first officer again said; 'the rudder is stuck.' I took the aircraft and disengaged the autopilot and pushed on the left rudder until it broke free; causing the aircraft to yaw hard to the left due to the amount of force I had applied to free it. Then; the rudders seemed to work normally again; I could move the rudder pedals normally with my toes. I gave the aircraft control back to the first officer and he also said the rudder pedals felt fine. Shortly after that; he said they were locked up again. He and I could free them each time they locked up using much greater force than normal. The yaw was not as severe since we were now flying slower; being vectored onto the ILS. I believe they locked up at least 3-5 times. We did not declare an emergency. I felt the aircraft was flying normally during the arrival and approach. There seemed to be no danger.

Original NASA ASRS Text

Title: A Q400 flight crew encountered recurring resistance to rudder inputs during the descent.

Narrative: While leveling at 12;000ft and slowing to 250K; we received permission to speed up; so the First Officer applied power and needed to also apply right rudder to compensate for the yaw caused by the increase in power. I was talking to company during this time when I felt the aircraft yaw hard to the right. I asked; 'What happened?' The First Officer replied; 'The rudder was stuck.' We then needed to keep descending and slowing and with power pulled back we needed left rudder to compensate for the power change. The First Officer again said; 'The rudder is stuck.' I took the aircraft and disengaged the autopilot and pushed on the left rudder until it broke free; causing the aircraft to yaw hard to the left due to the amount of force I had applied to free it. Then; the rudders seemed to work normally again; I could move the rudder pedals normally with my toes. I gave the aircraft control back to the First Officer and he also said the rudder pedals felt fine. Shortly after that; he said they were locked up again. He and I could free them each time they locked up using much greater force than normal. The yaw was not as severe since we were now flying slower; being vectored onto the ILS. I believe they locked up at least 3-5 times. We did not declare an emergency. I felt the aircraft was flying normally during the arrival and approach. There seemed to be no danger.

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	881175
Time
Date	201003
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	Q400
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Component
Aircraft Component	Rudder Control System
Person 1
Function	Pilot Not Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Pilot Flying First Officer
Qualification	Flight Crew Commercial
Events
Anomaly	Aircraft Equipment Problem Critical Inflight Event / Encounter Loss Of Aircraft Control