An air carrier B737 flight crew get a 'wing body overheat' warning illuminated and after completing ...

Attributes
ACN	377964
Time
Date	199708
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : ktn
State Reference	AK
Altitude	msl bound lower : 5000 msl bound upper : 5000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zan
Operator	common carrier : air carrier
Make Model Name	B737-400
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi pilot : flight engineer
Experience	flight time last 90 days : 100 flight time total : 14000 flight time type : 1400
ASRS Report	377964
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

We did a no bleeds takeoff from ktn because of a tailwind using the APU to pressurize the aircraft. After re- establishing the bleeds to a normal confign, we got a master caution light air conditioning 'wing body overheat right side.' we did the checklist, to shut off all bleed air sources to that side. The light remained on, but it takes time to cool and the light flickered a few times. We continued climbing out of the WX (light icing to on top). Contacted maintenance control and dispatch. We changed our alternate to juneau (a maintenance station and the WX was VFR as compared to sitka, our original destination, which was IFR and I suspected light icing). As we leveled off at cruise, FL260, the wing body overheat went out and remained out. We landed without any problems. The mechanic did a preliminary inspection and found no bleed leak. We changed aircraft and continued on. Our decision to go on to juneau and not return to ktn or land at our destination, sitka, were based on several factors. 1) after isolating the right side from any bleed air, I knew it would take time to cool and the checklist does not call for an immediate landing. 2) the WX at sitka was marginal and there is limited maintenance there, and there was the possible chance of icing on the approach. The WX at our departure also had a chance of icing. 3) juneau was VFR. It was our next stop after sitka. It was a larger maintenance base than ktn. The wing body overheat light was on for approximately 12-15 mins before going out for good. If I had to do it over again, I might have just made a 180 degree turn and landed back at ktn. I would look at changing our checklist covering the wing body overheat to read 'if light remains illuminated after a certain time, land at the nearest suitable airport. Caution no wing anti-ice available on the effected side.'

Original NASA ASRS Text

Title: AN ACR B737 FLC GET A 'WING BODY OVERHEAT' WARNING ILLUMINATED AND AFTER COMPLETING THE PROC DECIDE TO CONTINUE THEIR FLT'S FINAL DEST, OVERFLYING AN INTERMEDIATE STOP BECAUSE OF WX. THE RPTR REASONS NOW THAT RETURNING TO KTN MAY HAVE BEEN MORE PRUDENT. NO EMER DECLARATION.

Narrative: WE DID A NO BLEEDS TKOF FROM KTN BECAUSE OF A TAILWIND USING THE APU TO PRESSURIZE THE ACFT. AFTER RE- ESTABLISHING THE BLEEDS TO A NORMAL CONFIGN, WE GOT A MASTER CAUTION LIGHT AIR CONDITIONING 'WING BODY OVERHEAT R SIDE.' WE DID THE CHKLIST, TO SHUT OFF ALL BLEED AIR SOURCES TO THAT SIDE. THE LIGHT REMAINED ON, BUT IT TAKES TIME TO COOL AND THE LIGHT FLICKERED A FEW TIMES. WE CONTINUED CLBING OUT OF THE WX (LIGHT ICING TO ON TOP). CONTACTED MAINT CTL AND DISPATCH. WE CHANGED OUR ALTERNATE TO JUNEAU (A MAINT STATION AND THE WX WAS VFR AS COMPARED TO SITKA, OUR ORIGINAL DEST, WHICH WAS IFR AND I SUSPECTED LIGHT ICING). AS WE LEVELED OFF AT CRUISE, FL260, THE WING BODY OVERHEAT WENT OUT AND REMAINED OUT. WE LANDED WITHOUT ANY PROBS. THE MECH DID A PRELIMINARY INSPECTION AND FOUND NO BLEED LEAK. WE CHANGED ACFT AND CONTINUED ON. OUR DECISION TO GO ON TO JUNEAU AND NOT RETURN TO KTN OR LAND AT OUR DEST, SITKA, WERE BASED ON SEVERAL FACTORS. 1) AFTER ISOLATING THE R SIDE FROM ANY BLEED AIR, I KNEW IT WOULD TAKE TIME TO COOL AND THE CHKLIST DOES NOT CALL FOR AN IMMEDIATE LNDG. 2) THE WX AT SITKA WAS MARGINAL AND THERE IS LIMITED MAINT THERE, AND THERE WAS THE POSSIBLE CHANCE OF ICING ON THE APCH. THE WX AT OUR DEP ALSO HAD A CHANCE OF ICING. 3) JUNEAU WAS VFR. IT WAS OUR NEXT STOP AFTER SITKA. IT WAS A LARGER MAINT BASE THAN KTN. THE WING BODY OVERHEAT LIGHT WAS ON FOR APPROX 12-15 MINS BEFORE GOING OUT FOR GOOD. IF I HAD TO DO IT OVER AGAIN, I MIGHT HAVE JUST MADE A 180 DEG TURN AND LANDED BACK AT KTN. I WOULD LOOK AT CHANGING OUR CHKLIST COVERING THE WING BODY OVERHEAT TO READ 'IF LIGHT REMAINS ILLUMINATED AFTER A CERTAIN TIME, LAND AT THE NEAREST SUITABLE ARPT. CAUTION NO WING ANTI-ICE AVAILABLE ON THE EFFECTED SIDE.'

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.