|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1801 To 2400|
|Locale Reference||airport : mci.airport|
|Altitude||agl single value : 0|
|Operator||common carrier : air carrier|
|Make Model Name||B737-700|
|Operating Under FAR Part||Part 121|
|Navigation In Use||other|
|Flight Phase||ground : parked|
|Affiliation||company : air carrier|
|Function||flight crew : captain|
oversight : pic
|Qualification||pilot : atp|
|Experience||flight time last 90 days : 150|
flight time total : 10500
flight time type : 6500
|Affiliation||company : air carrier|
|Function||flight crew : first officer|
|Anomaly||other anomaly other|
|Independent Detector||other other : gnd 3|
|Problem Areas||Environmental Factor|
|Primary Problem||Environmental Factor|
Wing icing due to cold fuel built up much slower than expected. We arrived early in mci (from oak) so we had a 45 min turn at the gate. About 25 mins after arrival, I checked the wings. The bottom of the right wing had a thin layer of frost under the fuel tank and the left wing was just wet. (As a reminder, our exact limits are 'frost up to 1/8 inch thick on the lower wing surfaces due to cold fuel is permissible' for takeoff. Fom limitation section). The tops of both wings were clean. However, during the next 15 mins of this unusually long turn, ice continued to form under the wings and on top as well. Fortunately, a ramper came to the cockpit to ask about the icing. In my mind, I had checked the wings quite a while after arriving at the gate -- and after having been refueled -- and the wing icing was within limits to depart without deicing. Had it not been for the vigilance of a ramper spurring me to look again, I may not have discovered the increased icing. So because the wing top surfaces had small amounts of ice and the bottom of one was pushing the 1/8 inch limit, we deiced prior to departure. I submit this report because I'm surprised that this ice formed so slowly/or so late. I've assumed in the past that fuel in the truck or hydrant system would be much warmer than freezing, and that refueling a dash 700 would warm the cold soaked fuel in the wing tanks. As a result of this experience, I would recommend checking dash 700 wings for cold fuel induced icing as close as possible to push time.
Original NASA ASRS Text
Title: FROST AND ICE BUILD-UP ON THE WINGS DUE TO COLD SOAKED FUEL DURING A LAYOVER AFTER THE THOROUGH PREFLT INSPECTION IS MADE. THE DISCOVERY IS MADE BY RAMP PERSONNEL AND DEICING IS ACCOMPLISHED.
Narrative: WING ICING DUE TO COLD FUEL BUILT UP MUCH SLOWER THAN EXPECTED. WE ARRIVED EARLY IN MCI (FROM OAK) SO WE HAD A 45 MIN TURN AT THE GATE. ABOUT 25 MINS AFTER ARR, I CHKED THE WINGS. THE BOTTOM OF THE R WING HAD A THIN LAYER OF FROST UNDER THE FUEL TANK AND THE L WING WAS JUST WET. (AS A REMINDER, OUR EXACT LIMITS ARE 'FROST UP TO 1/8 INCH THICK ON THE LOWER WING SURFACES DUE TO COLD FUEL IS PERMISSIBLE' FOR TKOF. FOM LIMITATION SECTION). THE TOPS OF BOTH WINGS WERE CLEAN. HOWEVER, DURING THE NEXT 15 MINS OF THIS UNUSUALLY LONG TURN, ICE CONTINUED TO FORM UNDER THE WINGS AND ON TOP AS WELL. FORTUNATELY, A RAMPER CAME TO THE COCKPIT TO ASK ABOUT THE ICING. IN MY MIND, I HAD CHKED THE WINGS QUITE A WHILE AFTER ARRIVING AT THE GATE -- AND AFTER HAVING BEEN REFUELED -- AND THE WING ICING WAS WITHIN LIMITS TO DEPART WITHOUT DEICING. HAD IT NOT BEEN FOR THE VIGILANCE OF A RAMPER SPURRING ME TO LOOK AGAIN, I MAY NOT HAVE DISCOVERED THE INCREASED ICING. SO BECAUSE THE WING TOP SURFACES HAD SMALL AMOUNTS OF ICE AND THE BOTTOM OF ONE WAS PUSHING THE 1/8 INCH LIMIT, WE DEICED PRIOR TO DEP. I SUBMIT THIS RPT BECAUSE I'M SURPRISED THAT THIS ICE FORMED SO SLOWLY/OR SO LATE. I'VE ASSUMED IN THE PAST THAT FUEL IN THE TRUCK OR HYDRANT SYS WOULD BE MUCH WARMER THAN FREEZING, AND THAT REFUELING A DASH 700 WOULD WARM THE COLD SOAKED FUEL IN THE WING TANKS. AS A RESULT OF THIS EXPERIENCE, I WOULD RECOMMEND CHKING DASH 700 WINGS FOR COLD FUEL INDUCED ICING AS CLOSE AS POSSIBLE TO PUSH TIME.
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.