Narrative:

While we were taxiing for takeoff (#4 sequence), tower reported national WX service observation of light freezing rain. #1 aircraft questioned this and tower responded he didn't see it either, but that this was the current observation. I checked, unheated areas of my aircraft and painted surfaces on taxiway and saw no evidence of freezing rain. #1 aircraft, went off frequency to talk to dispatch and about 4-5 mins later requested and received takeoff clearance. #2 and #3 got out off-line and went to deicing area to request an inspection. I opened my side window and stuck head and shoulders out and touched several unheated surfaces to ensure that precipitation was liquid and was staying that way. Outside air temperature was +1 degree to +2 degrees C. I asked clearance for takeoff and was cleared onto runway to hold. While I held, tower put out report of moderate freezing rain. Outside air temperature was still +1 degree C or more, and visibility was 3-4 mi, so it definitely was moderate precipitation and was still staying liquid. Tower asked if we still wanted to take off and I said 'yes, I got takeoff clearance.' takeoff and aircraft performance were perfectly normal. 1 1/2 days later, I checked with our meteorology department and they said they'd been having this problem due to inexperienced observers working for NWS. For example, on morning of same day, NWS was reporting moderate freezing rain with a visibility of 4 mi and outside air temperature of 3 degrees C. We had requested and received an overwing inspection prior to taxi and there was no ice present. These inaccurate reports cause major delays and unnecessary expense. The observers need better training.

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Original NASA ASRS Text

Title: A DC9 FLT CREWTAKES OFF AFTER PERFORMING A CURSORY AIR FRAME CHK FROM THE COCKPIT AFTER RECEIVING A NWS WX RPT OF FREEZING RAIN AT DTW, MI.

Narrative: WHILE WE WERE TAXIING FOR TKOF (#4 SEQUENCE), TWR RPTED NATIONAL WX SVC OBSERVATION OF LIGHT FREEZING RAIN. #1 ACFT QUESTIONED THIS AND TWR RESPONDED HE DIDN'T SEE IT EITHER, BUT THAT THIS WAS THE CURRENT OBSERVATION. I CHKED, UNHEATED AREAS OF MY ACFT AND PAINTED SURFACES ON TXWY AND SAW NO EVIDENCE OF FREEZING RAIN. #1 ACFT, WENT OFF FREQ TO TALK TO DISPATCH AND ABOUT 4-5 MINS LATER REQUESTED AND RECEIVED TKOF CLRNC. #2 AND #3 GOT OUT OFF-LINE AND WENT TO DEICING AREA TO REQUEST AN INSPECTION. I OPENED MY SIDE WINDOW AND STUCK HEAD AND SHOULDERS OUT AND TOUCHED SEVERAL UNHEATED SURFACES TO ENSURE THAT PRECIP WAS LIQUID AND WAS STAYING THAT WAY. OUTSIDE AIR TEMP WAS +1 DEG TO +2 DEGS C. I ASKED CLRNC FOR TKOF AND WAS CLRED ONTO RWY TO HOLD. WHILE I HELD, TWR PUT OUT RPT OF MODERATE FREEZING RAIN. OUTSIDE AIR TEMP WAS STILL +1 DEG C OR MORE, AND VISIBILITY WAS 3-4 MI, SO IT DEFINITELY WAS MODERATE PRECIP AND WAS STILL STAYING LIQUID. TWR ASKED IF WE STILL WANTED TO TAKE OFF AND I SAID 'YES, I GOT TKOF CLRNC.' TKOF AND ACFT PERFORMANCE WERE PERFECTLY NORMAL. 1 1/2 DAYS LATER, I CHKED WITH OUR METEOROLOGY DEPT AND THEY SAID THEY'D BEEN HAVING THIS PROB DUE TO INEXPERIENCED OBSERVERS WORKING FOR NWS. FOR EXAMPLE, ON MORNING OF SAME DAY, NWS WAS RPTING MODERATE FREEZING RAIN WITH A VISIBILITY OF 4 MI AND OUTSIDE AIR TEMP OF 3 DEGS C. WE HAD REQUESTED AND RECEIVED AN OVERWING INSPECTION PRIOR TO TAXI AND THERE WAS NO ICE PRESENT. THESE INACCURATE RPTS CAUSE MAJOR DELAYS AND UNNECESSARY EXPENSE. THE OBSERVERS NEED BETTER TRAINING.

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.