Flight Crew Type 5000
Aircraft Equipment Problem Less Severe
Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; General Maintenance Action
Aircraft
Departing on our last flight of the day and fifth flight in that airplane we got a beta lockout warning horn. It started to blare at 50 FT above the ground and did not go off until 50 FT above the ground for landing. When the horn started to sound; both the Captain and I agreed that it was the sound of the beta lockout horn; the power levers were not behind or in the beta position and the lift gates were down. There was no indication of any problems via the engine instruments. We continued with the callouts and appropriate normal takeoff actions; and the After Takeoff checklist. We agreed that we should return to the field. I informed Departure Control of our intentions and we didn't feel it necessary to declare an emergency. I called the Flight Attendant to tell her of the return and made a PA to inform the passengers as well. I called Operations and informed them of our return. We landed with no complications and were in the air for less than 10 minutes. The horn is very loud and we have been trained that beta lockout problems usually occur a short height off the runway. Although this was not the engine surging that we have been trained for; we have heard the sound of the horn before and the place where it took place all fit. Beta lockout system failed. Remove the beta lockout system.
DHC8 First Officer experiences a beta lockout warning horn after lift off and since the horn cannot be silenced the crew elects to return to the departure airport.