DHC8 first officer reports a beta lockout failure shortly after takeoff. After complying with approp...

Narrative:

Shortly after selecting the landing gear up we noticed the #2 engine appeared to be surging. The prop RPM was fluctuating between 900 and approximately 1050 RPM; with the torque fluctuating between 80 and 100%. We both identified the problem as a beta lockout failure based on these indications. We continued the climb completing the after takeoff checklist and at 1500 ft completed the beta lockout failure after V1 checklist. Once the prop was pulled back to 900 RPM the engine ran smoothly thus further confirming we had properly identified the problem. The captain transferred the controls to me while he attempted to contact dispatch through operations; but was unsuccessful. The weather at our departure airport was 100 ft overcast with 1/2 mile visibility due to fog and ZZZ was our takeoff alternate. Given these circumstances we decided to continue the flight to ZZZ where the weather was VFR. The captain then informed the flight attendant of our situation and then I transferred the controls back to him. After checking in with approach control we declared an emergency; completed all normal checklists which included an announcement to the passengers; and landed uneventfully at ZZZ.

Original NASA ASRS Text

Title: DHC8 First Officer reports a beta lockout failure shortly after takeoff. After complying with appropriate checklist procedures; flight diverted to the takeoff alternate due to poor weather at their departure airport.

Narrative: Shortly after selecting the landing gear up we noticed the #2 engine appeared to be surging. The prop RPM was fluctuating between 900 and approximately 1050 RPM; with the torque fluctuating between 80 and 100%. We both identified the problem as a beta lockout failure based on these indications. We continued the climb completing the after takeoff checklist and at 1500 FT completed the beta lockout failure after V1 checklist. Once the prop was pulled back to 900 RPM the engine ran smoothly thus further confirming we had properly identified the problem. The Captain transferred the controls to me while he attempted to contact Dispatch through Operations; but was unsuccessful. The weather at our departure airport was 100 FT overcast with 1/2 mile visibility due to fog and ZZZ was our takeoff alternate. Given these circumstances we decided to continue the flight to ZZZ where the weather was VFR. The Captain then informed the Flight Attendant of our situation and then I transferred the controls back to him. After checking in with Approach Control we declared an emergency; completed all normal checklists which included an announcement to the passengers; and landed uneventfully at ZZZ.

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	881936
Time
Date	201004
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Dawn
Aircraft 1
Make Model Name	Dash 8-300
Operating Under FAR Part	Part 121
Flight Phase	Takeoff
Component
Aircraft Component	Propeller Control
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 240 Flight Crew Total 8000 Flight Crew Type 2700
Events
Anomaly	Aircraft Equipment Problem Critical

DHC8 first officer reports a beta lockout failure shortly after takeoff. After complying with appropriate checklist procedures; flight diverted to the takeoff alternate due to poor weather at their departure airport.