Narrative:

I turned on the lights to enhance our dining experience en route to mmgl. At the time VMC on top. I left the lights on after eating and every now and then checking outside. I could always see the stars clearly. I figured if we went IFR I would see the strobe flash. Somewhere central mexico, I noticed the EPR's split a little, so I turned on the engine anti-ice. The left engine EPR dropped so quickly to 1.2, I thought I had lost the left engine. I quickly recovered to normal. I then noticed the speed -- .67 mach. (.76 mach was set). I looked outside and we were skimming the tops of thin cirrus and picked up enough ice to coat the PF-2 probe and the engines had slowly reduced thrust while keeping the EPR's in the normal range.

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Original NASA ASRS Text

Title: MD80 CREW HAD ENG PT-2 PROBE ICING AND LOST AIRSPD.

Narrative: I TURNED ON THE LIGHTS TO ENHANCE OUR DINING EXPERIENCE ENRTE TO MMGL. AT THE TIME VMC ON TOP. I LEFT THE LIGHTS ON AFTER EATING AND EVERY NOW AND THEN CHKING OUTSIDE. I COULD ALWAYS SEE THE STARS CLRLY. I FIGURED IF WE WENT IFR I WOULD SEE THE STROBE FLASH. SOMEWHERE CENTRAL MEXICO, I NOTICED THE EPR'S SPLIT A LITTLE, SO I TURNED ON THE ENG ANTI-ICE. THE L ENG EPR DROPPED SO QUICKLY TO 1.2, I THOUGHT I HAD LOST THE L ENG. I QUICKLY RECOVERED TO NORMAL. I THEN NOTICED THE SPD -- .67 MACH. (.76 MACH WAS SET). I LOOKED OUTSIDE AND WE WERE SKIMMING THE TOPS OF THIN CIRRUS AND PICKED UP ENOUGH ICE TO COAT THE PF-2 PROBE AND THE ENGS HAD SLOWLY REDUCED THRUST WHILE KEEPING THE EPR'S IN THE NORMAL RANGE.

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.