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20121129029109I

Incident · No damage
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FAA incident report · Boeing 737-7H4 · Denver, CO · November 29, 2012

FAA Aviation Safety Information Portal

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Date
November 29, 2012 · 10:10 local
Place
Denver, CO
Airport
Denver International
Phase of flight
Takeoff: Climb Out
Operating rules
Air carrier (Part 121)
Operator
SWAA
Damage
No damage
Aircraft
N294WN
Reported as
Boeing 737-7H4
Reported engine
CFM International CFM56-7B24
People aboard
41
Fatal injuries
0
Other injuries
0
N294WNRegistered now · Boeing 737-7H4S/N 32540 · Built 2007Airframe modelBoeing 737-7H4Engine modelCFM International CFM56-7B24 seriesTurbo-fan

From the FAA’s Accident/Incident Data System (AIDS), through its Aviation Safety Information Portal, as reported. The NTSB investigates accidents separately, and its record of an accident is the fuller one. The aircraft is matched to the registry by N-number and event date, checked against the reported make and model; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

What happened

The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.

After takeoff (during climb out) the number 2 (right) engine experienced an uncommanded acceleration to 109 % N1. The flight crew disengaged the auto throttle system and reduced power on the number 2 engine. The number 2 engine power began to stabilize after the power was reduced. The aircrew elected to return to Denver International. As they initiated a turn to Denver, the number 2 engine rolled back to a sub-idle condition and experienced an over temperature condition and the aircrew shut it down. Near simultaneously, the number 1 engine recovered accelerated uncommanded to approximately 113 % N1. The number 1 engine recovered from the overspeed and the aircraft recovered safely on one engine at Denver International. The event can be classified as a dual overspeed due to the circumstances involved. Maintenance personnel inspected both engines for damage but could not identify any. FDR data indicates that the engines may have experienced several compressor stalls during the incident sequence however the aircrew did not note any compressor stalls. Both engines were replaced by the operator.

As the FAA filed it

AFTER TAKEOFF (DURING CLIMB OUT) THE NUMBER 2 (RIGHT) ENGINE EXPERIENCED AN UNCOMMANDED ACCELERATION TO 109 % N1. THE FLIGHT CREW DISENGAGED THE AUTO THROTTLE SYSTEM AND REDUCED POWER ON THE NUMBER 2 ENGINE. THE NUMBER 2 ENGINE POWER BEGAN TO STABILIZE AFTER THE POWER WAS REDUCED. THE AIRCREW ELECTED TO RETURN TO DENVER INTERNATIONAL. AS THEY INITIATED A TURN TO DENVER, THE NUMBER 2 ENGINE ROLLED BACK TO A SUB-IDLE CONDITION AND EXPERIENCED AN OVER TEMPERATURE CONDITION AND THE AIRCREW SHUT IT DOWN. NEAR SIMULTANEOUSLY, THE NUMBER 1 ENGINE RECOVERED ACCELERATED UNCOMMANDED TO APPROXIMATELY 113 % N1. THE NUMBER 1 ENGINE RECOVERED FROM THE OVERSPEED AND THE AIRCRAFT RECOVERED SAFELY ON ONE ENGINE AT DENVER INTERNATIONAL. THE EVENT CAN BE CLASSIFIED AS A DUAL OVERSPEED DUE TO THE CIRCUMSTANCES INVOLVED. MAINTENANCE PERSONNEL INSPECTED BOTH ENGINES FOR DAMAGE BUT COULD NOT IDENTIFY ANY. FDR DATA INDICATES THAT THE ENGINES MAY HAVE EXPERIENCED SEVERAL COMPRESSOR STALLS DURING THE INCIDENT SEQUENCE HOWEVER THE AIRCREW DID NOT NOTE ANY COMPRESSOR STALLS. BOTH ENGINES WERE REPLACED BY THE OPERATOR.