Return land mandated by intermittent engine fire warning.

Attributes
ACN	284773
Time
Date	199410
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : msp
State Reference	MN
Altitude	msl bound lower : 11000 msl bound upper : 12000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : msp tower : act
Operator	common carrier : air carrier
Make Model Name	B727-200
Operating Under FAR Part	other : unknown
Flight Phase	climbout : intermediate altitude landing other other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 230 flight time total : 35600 flight time type : 7000
ASRS Report	284773
Person 2
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : instrument pilot : commercial pilot : flight engineer
Experience	flight time last 90 days : 0 flight time total : 1300 flight time type : 0
ASRS Report	285156
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : declared emergency none taken : unable other
Consequence	other
Supplementary
Primary Problem	Aircraft

Narrative:

Climbing/accelerating out of 10000 ft and intermittent fire warning occurred on engine #2 -- power was immediately reduced on that engine and the fire warning discontinued. Power was advanced above 400 degrees centigrade egt and the fire warning began intermittently again. Power was reduced to idle thrust and no fire warning indications were encountered -- suspected a bleed-air duct failure and returned immediately to msp. Landed uneventfully, visual external inspection ok, shut down engine. After clearing runway and when cowling was opened, found a bleed-air duct had broken at the firewall clamp putting hot bleed-air on the fire detection system. All sops adhered to. Supplemental information from acn 285156: initially the crew thought we had a malfunctioning fire detect system. When it seemed to respond to power reductions, we then thought it was a bleed problem. Supplemental information from acn 285414: no secondary fire indications (high egt, high oil temperature) were noted. Additionally, there were no indications of an aft body overheat. Our crew (including the check airman) believed this to be an indication problem. No emergency was declared. The #2 firewall had also sustained damage. The crew incorrectly determined it was a faulty indication. The indication, however, was valid and was alerting our crew to a problem with our #2 engine.

Original NASA ASRS Text

Title: RETURN LAND MANDATED BY INTERMITTENT ENG FIRE WARNING.

Narrative: CLBING/ACCELERATING OUT OF 10000 FT AND INTERMITTENT FIRE WARNING OCCURRED ON ENG #2 -- PWR WAS IMMEDIATELY REDUCED ON THAT ENG AND THE FIRE WARNING DISCONTINUED. PWR WAS ADVANCED ABOVE 400 DEGS CENTIGRADE EGT AND THE FIRE WARNING BEGAN INTERMITTENTLY AGAIN. PWR WAS REDUCED TO IDLE THRUST AND NO FIRE WARNING INDICATIONS WERE ENCOUNTERED -- SUSPECTED A BLEED-AIR DUCT FAILURE AND RETURNED IMMEDIATELY TO MSP. LANDED UNEVENTFULLY, VISUAL EXTERNAL INSPECTION OK, SHUT DOWN ENG. AFTER CLRING RWY AND WHEN COWLING WAS OPENED, FOUND A BLEED-AIR DUCT HAD BROKEN AT THE FIREWALL CLAMP PUTTING HOT BLEED-AIR ON THE FIRE DETECTION SYS. ALL SOPS ADHERED TO. SUPPLEMENTAL INFO FROM ACN 285156: INITIALLY THE CREW THOUGHT WE HAD A MALFUNCTIONING FIRE DETECT SYS. WHEN IT SEEMED TO RESPOND TO PWR REDUCTIONS, WE THEN THOUGHT IT WAS A BLEED PROB. SUPPLEMENTAL INFO FROM ACN 285414: NO SECONDARY FIRE INDICATIONS (HIGH EGT, HIGH OIL TEMP) WERE NOTED. ADDITIONALLY, THERE WERE NO INDICATIONS OF AN AFT BODY OVERHEAT. OUR CREW (INCLUDING THE CHK AIRMAN) BELIEVED THIS TO BE AN INDICATION PROB. NO EMER WAS DECLARED. THE #2 FIREWALL HAD ALSO SUSTAINED DAMAGE. THE CREW INCORRECTLY DETERMINED IT WAS A FAULTY INDICATION. THE INDICATION, HOWEVER, WAS VALID AND WAS ALERTING OUR CREW TO A PROB WITH OUR #2 ENG.

Data retrieved from NASA's ASRS site as of July 2007 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.