What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
On 2/10/2016, at approximately 0855 EST, a commutair DHC-8-202 aircraft while flying as united express flight 4775, on departure from Albany international(alb) through V1, #1 engine failed and auto-feathered on take-off. The crew ran emergency checklist and per checklist shut down engine and retuned to field. Declared an emergency, and landed safely without incident.
Commutair's Albany main maintenance base mechanics began an investigation into the incident throughout the remainder of the day. A bulleted list of findings and facts were forwarded to the certificate management team by the operators chief inspector as below:
· Today's engine event was on an engine that was just replaced due to the life limited components timing out.
· The engine came out of the repair facility as an overhaul to the turbo-machinery and the reduction gear box.
· Inspected the entire engine assembly and found no discrepancies.
· Performed a resistance check of the engine wiring harnesses and found no discrepancies.
· Inspected and operationally checked all of the micro switches that are associated with, and provide input to, the autofeather system and found no discrepancies.
· Inspected the associated connectors to ensure that the connector care program was properly complied with during the engine change and found them to be satisfactory.
· Although not mandatory, Bombardier recommends that torque signal condition units (tscu) be matched in regards to model number on the same aircraft (2 per aircraft, 1 per side) and we found that the units were not matched. Several years ago, we added supplements to the amm and ipc directing the technicians to match the tscu's if at all possible when replacing one. In addition to the supplements, a maintenance information letter (mil), was issued to all maintenance personnel to make them aware of this procedure.
· All indications, based on our operating experience and vendor teardown reports, led us to replace the associated tscu. These units are composed of solder joints, circuit boards and relays which operate in the harsh conditions of constant heat and vibration.
· The facts related to this suspect tscu are:
O part number: 30005-0000-56
O serial number: MM5100
O removed from aircraft N375PH on 10/20/2014 due to "aborted takeoff due to autofeather not arming"
O it was inspected by the vendor and the fault was not confirmed (refer to attached teardown report). It was inspected, tested and returned to service by the vendor
O it was installed on the current aircraft, N367PH on 12/02/2014 and has been on wing for 1694.8 hours and 1950 cycles
O the unit has the following total times and cycles:
§ TSO: 30224.1
§ Cso: 40530
§ Tsn: 30224.1
§ Csn: 40530
· We replaced the suspect tscu with a model number that matches the model number of the unit on the other side of the aircraft, as per Bombardier recommendations and our own sop's.
· An operational check flight will be performed prior to return to service.
Considering the listed facts above, an Albany based maintenance supervisor for the operator made the decision to replace the #2 tscu for the autofeather issue. Multiple ground operation tests were performed with satisfactory results. An operation check flight was requested prior to entering the aircraft back into revenue flight, and the test flight returned satisfactory as well.
11 Days later, on 2/21/2016 at approximately 13:20 EST this aircraft had a repeat of this incident with an #1 prop autofeather event occurring at take-off rotation at Washington dulles airport(iad). Refer to AEA0116010 for details regarding this incident.
As the FAA filed it
ON 2/10/2016, AT APPROXIMATELY 0855 EST, A COMMUTAIR DHC-8-202 AIRCRAFT WHILE FLYING AS UNITED EXPRESS FLIGHT 4775, ON DEPARTURE FROM ALBANY INTERNATIONAL(ALB) THROUGH V1, #1 ENGINE FAILED AND AUTO-FEATHERED ON TAKE-OFF. THE CREW RAN EMERGENCY CHECKLIST AND PER CHECKLIST SHUT DOWN ENGINE AND RETUNED TO FIELD. DECLARED AN EMERGENCY, AND LANDED SAFELY WITHOUT INCIDENT.
COMMUTAIR'S ALBANY MAIN MAINTENANCE BASE MECHANICS BEGAN AN INVESTIGATION INTO THE INCIDENT THROUGHOUT THE REMAINDER OF THE DAY. A BULLETED LIST OF FINDINGS AND FACTS WERE FORWARDED TO THE CERTIFICATE MANAGEMENT TEAM BY THE OPERATORS CHIEF INSPECTOR AS BELOW:
· TODAY'S ENGINE EVENT WAS ON AN ENGINE THAT WAS JUST REPLACED DUE TO THE LIFE LIMITED COMPONENTS TIMING OUT.
· THE ENGINE CAME OUT OF THE REPAIR FACILITY AS AN OVERHAUL TO THE TURBO-MACHINERY AND THE REDUCTION GEAR BOX.
· INSPECTED THE ENTIRE ENGINE ASSEMBLY AND FOUND NO DISCREPANCIES.
· PERFORMED A RESISTANCE CHECK OF THE ENGINE WIRING HARNESSES AND FOUND NO DISCREPANCIES.
· INSPECTED AND OPERATIONALLY CHECKED ALL OF THE MICRO SWITCHES THAT ARE ASSOCIATED WITH, AND PROVIDE INPUT TO, THE AUTOFEATHER SYSTEM AND FOUND NO DISCREPANCIES.
· INSPECTED THE ASSOCIATED CONNECTORS TO ENSURE THAT THE CONNECTOR CARE PROGRAM WAS PROPERLY COMPLIED WITH DURING THE ENGINE CHANGE AND FOUND THEM TO BE SATISFACTORY.
· ALTHOUGH NOT MANDATORY, BOMBARDIER RECOMMENDS THAT TORQUE SIGNAL CONDITION UNITS (TSCU) BE MATCHED IN REGARDS TO MODEL NUMBER ON THE SAME AIRCRAFT (2 PER AIRCRAFT, 1 PER SIDE) AND WE FOUND THAT THE UNITS WERE NOT MATCHED. SEVERAL YEARS AGO, WE ADDED SUPPLEMENTS TO THE AMM AND IPC DIRECTING THE TECHNICIANS TO MATCH THE TSCU'S IF AT ALL POSSIBLE WHEN REPLACING ONE. IN ADDITION TO THE SUPPLEMENTS, A MAINTENANCE INFORMATION LETTER (MIL), WAS ISSUED TO ALL MAINTENANCE PERSONNEL TO MAKE THEM AWARE OF THIS PROCEDURE.
· ALL INDICATIONS, BASED ON OUR OPERATING EXPERIENCE AND VENDOR TEARDOWN REPORTS, LED US TO REPLACE THE ASSOCIATED TSCU. THESE UNITS ARE COMPOSED OF SOLDER JOINTS, CIRCUIT BOARDS AND RELAYS WHICH OPERATE IN THE HARSH CONDITIONS OF CONSTANT HEAT AND VIBRATION.
· THE FACTS RELATED TO THIS SUSPECT TSCU ARE:
O PART NUMBER: 30005-0000-56
O SERIAL NUMBER: MM5100
O REMOVED FROM AIRCRAFT N375PH ON 10/20/2014 DUE TO "ABORTED TAKEOFF DUE TO AUTOFEATHER NOT ARMING"
O IT WAS INSPECTED BY THE VENDOR AND THE FAULT WAS NOT CONFIRMED (REFER TO ATTACHED TEARDOWN REPORT). IT WAS INSPECTED, TESTED AND RETURNED TO SERVICE BY THE VENDOR
O IT WAS INSTALLED ON THE CURRENT AIRCRAFT, N367PH ON 12/02/2014 AND HAS BEEN ON WING FOR 1694.8 HOURS AND 1950 CYCLES
O THE UNIT HAS THE FOLLOWING TOTAL TIMES AND CYCLES:
§ TSO: 30224.1
§ CSO: 40530
§ TSN: 30224.1
§ CSN: 40530
· WE REPLACED THE SUSPECT TSCU WITH A MODEL NUMBER THAT MATCHES THE MODEL NUMBER OF THE UNIT ON THE OTHER SIDE OF THE AIRCRAFT, AS PER BOMBARDIER RECOMMENDATIONS AND OUR OWN SOP'S.
· AN OPERATIONAL CHECK FLIGHT WILL BE PERFORMED PRIOR TO RETURN TO SERVICE.
CONSIDERING THE LISTED FACTS ABOVE, AN ALBANY BASED MAINTENANCE SUPERVISOR FOR THE OPERATOR MADE THE DECISION TO REPLACE THE #2 TSCU FOR THE AUTOFEATHER ISSUE. MULTIPLE GROUND OPERATION TESTS WERE PERFORMED WITH SATISFACTORY RESULTS. AN OPERATION CHECK FLIGHT WAS REQUESTED PRIOR TO ENTERING THE AIRCRAFT BACK INTO REVENUE FLIGHT, AND THE TEST FLIGHT RETURNED SATISFACTORY AS WELL.
11 DAYS LATER, ON 2/21/2016 AT APPROXIMATELY 13:20 EST THIS AIRCRAFT HAD A REPEAT OF THIS INCIDENT WITH AN #1 PROP AUTOFEATHER EVENT OCCURRING AT TAKE-OFF ROTATION AT WASHINGTON DULLES AIRPORT(IAD). REFER TO AEA0116010 FOR DETAILS REGARDING THIS INCIDENT.
Other reports on N367PH · 3
Matched to the same aircraft by N-number and date.