Narrative:

Inbound aircraft arrived on time and after towing from international terminal I boarded aircraft and briefed flight attendants. Upon looking through the cabin; I did a cursory look out the overwing windows and noticed a sheet of ice on both wing roots. I notified maintenance and they sent a mechanic out several mins later; who shortly thereafter declared that all the ice was melted. From my previous experience on the MD80; and knowing that ice of those proportions takes a while to melt; I had a suspicion that the ice was still there. I did another check from inside the cabin and sure enough the same ice sheets were still present. I notified maintenance and they sent out the mechanic again; and we both visually inspected the wing root from the cabin. Upon seeing the ice; the mechanic declared that it was going to be a 1.5 hour delay. This turned out to not be the case; but it points out a serious deficiency in the ice inspection process for the B737. 1) the higher wings on the B737 (especially the ng's) do not allow a good vantage point for the mechanics to visually inspect the wings from their existing ladders. 2) there is no anti-skid feature for the mechanics to 'feel' a difference (or not) as on the MD80's. 3) I think there is a belief that this is an MD80-only problem and not as much a concern for the B737 fleet. 4) flight crews need to take the time to look for themselves to ensure the wings are clear. This aircraft came in from a long flight with extra super-cooled fuel (I assume for anticipated arrival delays) into a humid environment. These conditions should trigger a bright light in everybody's head to be on the watch for the potential for wing icing to develop. I think with our longer range flts this is an issue many are not adequately aware of. For both pilots and maintenance -- emphasize to all concerned to be aware that this is a serious threat that deserves increased attention.

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Original NASA ASRS Text

Title: B737-800 CAPT REPORTS DISCOVERING ICE ON UPPER WING ROOT DURING PREFLIGHT AFTER LONG FLIGHT. NO PRECIPITATION WAS FALLING.

Narrative: INBOUND ACFT ARRIVED ON TIME AND AFTER TOWING FROM INTL TERMINAL I BOARDED ACFT AND BRIEFED FLT ATTENDANTS. UPON LOOKING THROUGH THE CABIN; I DID A CURSORY LOOK OUT THE OVERWING WINDOWS AND NOTICED A SHEET OF ICE ON BOTH WING ROOTS. I NOTIFIED MAINT AND THEY SENT A MECH OUT SEVERAL MINS LATER; WHO SHORTLY THEREAFTER DECLARED THAT ALL THE ICE WAS MELTED. FROM MY PREVIOUS EXPERIENCE ON THE MD80; AND KNOWING THAT ICE OF THOSE PROPORTIONS TAKES A WHILE TO MELT; I HAD A SUSPICION THAT THE ICE WAS STILL THERE. I DID ANOTHER CHK FROM INSIDE THE CABIN AND SURE ENOUGH THE SAME ICE SHEETS WERE STILL PRESENT. I NOTIFIED MAINT AND THEY SENT OUT THE MECH AGAIN; AND WE BOTH VISUALLY INSPECTED THE WING ROOT FROM THE CABIN. UPON SEEING THE ICE; THE MECH DECLARED THAT IT WAS GOING TO BE A 1.5 HR DELAY. THIS TURNED OUT TO NOT BE THE CASE; BUT IT POINTS OUT A SERIOUS DEFICIENCY IN THE ICE INSPECTION PROCESS FOR THE B737. 1) THE HIGHER WINGS ON THE B737 (ESPECIALLY THE NG'S) DO NOT ALLOW A GOOD VANTAGE POINT FOR THE MECHS TO VISUALLY INSPECT THE WINGS FROM THEIR EXISTING LADDERS. 2) THERE IS NO ANTI-SKID FEATURE FOR THE MECHS TO 'FEEL' A DIFFERENCE (OR NOT) AS ON THE MD80'S. 3) I THINK THERE IS A BELIEF THAT THIS IS AN MD80-ONLY PROB AND NOT AS MUCH A CONCERN FOR THE B737 FLEET. 4) FLT CREWS NEED TO TAKE THE TIME TO LOOK FOR THEMSELVES TO ENSURE THE WINGS ARE CLR. THIS ACFT CAME IN FROM A LONG FLT WITH EXTRA SUPER-COOLED FUEL (I ASSUME FOR ANTICIPATED ARR DELAYS) INTO A HUMID ENVIRONMENT. THESE CONDITIONS SHOULD TRIGGER A BRIGHT LIGHT IN EVERYBODY'S HEAD TO BE ON THE WATCH FOR THE POTENTIAL FOR WING ICING TO DEVELOP. I THINK WITH OUR LONGER RANGE FLTS THIS IS AN ISSUE MANY ARE NOT ADEQUATELY AWARE OF. FOR BOTH PLTS AND MAINT -- EMPHASIZE TO ALL CONCERNED TO BE AWARE THAT THIS IS A SERIOUS THREAT THAT DESERVES INCREASED ATTN.

Data retrieved from NASA's ASRS site as of May 2009 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.