Narrative:

I originated this aircraft and it had multiple maintenance issues; all with prior history. First; there was a fluid leak and loose canister in the #1 engine found during the preflight inspection. Contract maintenance fixed those issues. While they were completing the paperwork and prior to boarding; the APU had an automatic shutdown and triggered a check fire detection warning light. The aircraft was inspected by contract maintenance and the APU and its fire detection system were then meled. The APU had a similar maintenance history a few days prior. Also; a few days prior; another crew experienced an inflight beta lockout failure at 8;000 feet with torque surging in both engines. Following that event; the beta lockout system was supposed to be meled and deactivated by maintenance and indicated so for my flight; both in the logbook and release.after takeoff at approximately 400 feet; after the engine bleeds were turned on; we experienced simultaneous and continuous torque surging in both engines +/- 15%; up to ~105% torque and a drop to ~75%. This condition continued until torque was reduced to ~45%. I suspected a beta lockout failure; but we were not experiencing all the tell-tale signs of a beta lockout (no prop RPM cycling and possible ground range warning lights). Further; since the beta lockout system was supposed to be MEL'd we should not have had a failure since it should have been deactivated; so we were operating with an unknown engine condition with dual engine surging and a lack of full control over them; I elected to level out at 4;000 feet and request a return to [departure airport].also; had we continued the flight; our routing would take us over the ocean; not an area I wanted to be in with engine issues. The aircraft was controllable and the surging stopped only after torque was reduced; so it was just a precautionary landing with no [priority handling requested]. I requested vectors for a 15 mile downwind which gave the first officer and I time to complete the appropriate checklists and briefs. The first officer briefed the flight attendant to prepare for a return; no brace or emergency; normal landing; and I notified the passengers of the precautionary landing. Airport rescue and fire fighting (arff) met the aircraft on landing; without our request; and followed us to the gate.after passenger deplaning; maintenance requested that I do multiple run-ups and tests alongside contract maintenance. Several high powered run-ups were performed on the runway and maintenance directed contract maintenance through the phone to pull weight-on-wheels circuit breakers not the runway without gear pins being installed; with me being at the controls. I did not agree to do this as it could have resulted in a gear-up situation on the ground. I decided we could return to the gate; shut down; install the gear pins; then go back out to the runway to do further tests.while at the gate; several circuit breakers were pulled and the anti-skid system turned off for the upcoming ground tests and run-up. After engine start and after start checklists were complete; while being marshaled off the gate; the normal toe brakes were very mushy and not stopping the aircraft; even though they had normal hydraulic and standby pressure and I had to apply the emergency brake to stop the aircraft. At this point I decided to halt any further testing and leave it completely to maintenance as the operation was crossing my safety thresholds. After the fact; maintenance mentioned that they should have mentioned about the braking condition with the tests being performed.inflight; dual engine simultaneous torque surging at 400 feet AGL with no associated warning or caution lights. The engines were audibly surging as well; so it was not just an indication.maintenance mentioned that this aircraft had a prior history of similar events with the torque surging and APU check fire detect warning issues. I suspect we suffered some sort of beta lockout system failure; but we should not have since it should have been deactivated. Either it wasn't properly deactivated by maintenance or there was some other unknown issue that caused it.precautionary return to field after briefing ATC; flight attendants; passengers; and completing appropriate checklists.ensure the beta lockout system is properly deactivated (if that was the cause.) do not allow contract maintenance to troubleshoot this complex system while only receiving guidance from [maintenance] over the phone. I realize this was an outstation and was difficult for mechanics to get to; but placing the burden on my flight crew and contract maintenance for troubleshooting created even more safety risks.

Related reports:

Google
 

Original NASA ASRS Text

Title: Dash-8 300 Captain reported a return to departure airport after experiencing surging in both engines.

Narrative: I originated this aircraft and it had multiple maintenance issues; all with prior history. First; there was a fluid leak and loose canister in the #1 engine found during the preflight inspection. Contract maintenance fixed those issues. While they were completing the paperwork and prior to boarding; the APU had an automatic shutdown and triggered a check fire detection warning light. The aircraft was inspected by contract maintenance and the APU and its fire detection system were then MELed. The APU had a similar maintenance history a few days prior. Also; a few days prior; another crew experienced an inflight beta lockout failure at 8;000 feet with torque surging in both engines. Following that event; the beta lockout system was supposed to be MELed and deactivated by maintenance and indicated so for my flight; both in the logbook and release.After takeoff at approximately 400 feet; after the engine bleeds were turned on; we experienced simultaneous and continuous torque surging in both engines +/- 15%; up to ~105% torque and a drop to ~75%. This condition continued until torque was reduced to ~45%. I suspected a beta lockout failure; but we were not experiencing all the tell-tale signs of a beta lockout (no prop RPM cycling and possible ground range warning lights). Further; since the beta lockout system was supposed to be MEL'd we should not have had a failure since it should have been deactivated; so we were operating with an unknown engine condition with dual engine surging and a lack of full control over them; I elected to level out at 4;000 feet and request a return to [departure airport].Also; had we continued the flight; our routing would take us over the Ocean; not an area I wanted to be in with engine issues. The aircraft was controllable and the surging stopped only after torque was reduced; so it was just a precautionary landing with no [priority handling requested]. I requested vectors for a 15 mile downwind which gave the First Officer and I time to complete the appropriate checklists and briefs. The First Officer briefed the flight attendant to prepare for a return; no brace or emergency; normal landing; and I notified the passengers of the precautionary landing. Airport Rescue and Fire Fighting (ARFF) met the aircraft on landing; without our request; and followed us to the gate.After passenger deplaning; maintenance requested that I do multiple run-ups and tests alongside contract maintenance. Several high powered run-ups were performed on the runway and maintenance directed contract maintenance through the phone to pull weight-on-wheels circuit breakers not the runway without gear pins being installed; with me being at the controls. I did not agree to do this as it could have resulted in a gear-up situation on the ground. I decided we could return to the gate; shut down; install the gear pins; then go back out to the runway to do further tests.While at the gate; several circuit breakers were pulled and the anti-skid system turned off for the upcoming ground tests and run-up. After engine start and after start checklists were complete; while being marshaled off the gate; the normal toe brakes were very mushy and not stopping the aircraft; even though they had normal hydraulic and standby pressure and I had to apply the emergency brake to stop the aircraft. At this point I decided to halt any further testing and leave it completely to maintenance as the operation was crossing my safety thresholds. After the fact; maintenance mentioned that they should have mentioned about the braking condition with the tests being performed.Inflight; dual engine simultaneous torque surging at 400 feet AGL with no associated warning or caution lights. The engines were audibly surging as well; so it was not just an indication.Maintenance mentioned that this aircraft had a prior history of similar events with the torque surging and APU check fire detect warning issues. I suspect we suffered some sort of beta lockout system failure; but we should not have since it should have been deactivated. Either it wasn't properly deactivated by maintenance or there was some other unknown issue that caused it.Precautionary return to field after briefing ATC; flight attendants; passengers; and completing appropriate checklists.Ensure the beta lockout system is properly deactivated (if that was the cause.) Do not allow contract maintenance to troubleshoot this complex system while only receiving guidance from [Maintenance] over the phone. I realize this was an outstation and was difficult for mechanics to get to; but placing the burden on my flight crew and contract maintenance for troubleshooting created even more safety risks.

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.