Narrative:

This incident was a GPWS mode I warning on ILS final, followed by a missed approach. It happened on the ILS to runway 24L at cle during turbulent daytime WX conditions. Descent and approach were normal until inside the FAF (engle NDB). The first officer was flying with the autoplt engaged. He briefed that he would fly reference +5 KTS on final approach because of wind gusts. Below 12000 ft the conditions were continuous light/occasional moderate chop. Clouds were layered from 12000 ft down to the GS intercept altitude. As we approached the FAF, we were in and out of ragged cloud bases but could see the ground below. The WX at cle was reported as 1000 ft broken and 3 mi visibility. At about 5 mi from the FAF we got an ATIS update stating that the RVR for runway 24L was 5000 ft. The wind was 300 degrees 15 KTS gusting 25 KTS. We configured for the approach normally, passed the FAF and switched to tower. As we crossed the FAF, we received an ACARS alert message for windshear at the airport with up to 15 KTS gain in airspeed. As I read the ACARS message, at about 4 mi on final and 2100 ft MSL, the tower broadcast a microburst alert for the airport. At this moment we could see the terrain and the approach lights ahead, but could not see the airport. There was a shower moving over the airport, but the visibility on final approach appeared to be about 3-4 mi. The conditions below us and to each side were clear. At the same time we began to experience a slight increase in turbulence. Airspeed fluctuated -0 to +15 KTS. The ivsi needle indicated -300 FPM momentarily, then swung to -1500 ft. The autoplt was not keeping up with the changes so the first officer immediately disconnected it and began hand-flying the approach. The ivsi was correcting to about 800 FPM. About a half second later, we heard the GPWS 'whoop, whoop, pull up.' the first officer immediately initiated a missed approach. The entire sequence from the microburst alert to the missed approach took about 2-3 seconds. The first officer and I advanced the thrust levers to the go around thrust setting (not the mechanical stops) and he rotated to the go around pitch attitude of 20 degrees. During the missed approach, the aircraft accelerated and climbed normally and we never saw any excessive loss of airspeed or altitude. We never received any cockpit windshear warning, and there was no stick shaker or buffet. We continued the missed approach normally, raised the gear and flaps, and switched to approach control as instructed by tower. The situation deteriorated quickly from the FAF to the point where we started the go around. We were both considering a go around but didn't have time to discuss it before we received the GPWS warning. We received the GPS warning at about 1300 ft AGL. Although the airport had a shower directly over it, we could clearly see the terrain and the approach lights 3-4 mi ahead. The missed approach was clearly warranted by the deteriorating conditions over the airport. But the GPWS maneuver with thrust levers at the stops seemed to be unnecessary based on our flight conditions and the performance of the aircraft. I did not see or feel the excessive sink rate that should be present in order to cause a mode I GPWS warning. Neither did the first officer. Approach control vectored us for a radar pattern to a second ILS approach. At least one other aircraft behind us also went missed approach. On downwind of the pattern, the first officer and I discussed holding to wait until the shower cleared the airport. The approach controller informed us that the shower was moving quickly across the field and would probably be clear of the airport before we got on final. We continued the pattern, and the first officer flew an uneventful approach and landing. On the second approach, the WX was about 1500 ft broken and 3 mi visibility.

Related reports:

Google
 

Original NASA ASRS Text

Title: AN ACR FLC HAS TO ABANDON THE APCH TO RWY 24L AFTER A NEAR LOSS OF ACFT CTL AND WINDSHEAR IS ENCOUNTERED AT 2000 FT MSL, ACTIVATING THE GPWS INTO A PULL UP COMMAND AT CLE, OH.

Narrative: THIS INCIDENT WAS A GPWS MODE I WARNING ON ILS FINAL, FOLLOWED BY A MISSED APCH. IT HAPPENED ON THE ILS TO RWY 24L AT CLE DURING TURBULENT DAYTIME WX CONDITIONS. DSCNT AND APCH WERE NORMAL UNTIL INSIDE THE FAF (ENGLE NDB). THE FO WAS FLYING WITH THE AUTOPLT ENGAGED. HE BRIEFED THAT HE WOULD FLY REF +5 KTS ON FINAL APCH BECAUSE OF WIND GUSTS. BELOW 12000 FT THE CONDITIONS WERE CONTINUOUS LIGHT/OCCASIONAL MODERATE CHOP. CLOUDS WERE LAYERED FROM 12000 FT DOWN TO THE GS INTERCEPT ALT. AS WE APCHED THE FAF, WE WERE IN AND OUT OF RAGGED CLOUD BASES BUT COULD SEE THE GND BELOW. THE WX AT CLE WAS RPTED AS 1000 FT BROKEN AND 3 MI VISIBILITY. AT ABOUT 5 MI FROM THE FAF WE GOT AN ATIS UPDATE STATING THAT THE RVR FOR RWY 24L WAS 5000 FT. THE WIND WAS 300 DEGS 15 KTS GUSTING 25 KTS. WE CONFIGURED FOR THE APCH NORMALLY, PASSED THE FAF AND SWITCHED TO TWR. AS WE CROSSED THE FAF, WE RECEIVED AN ACARS ALERT MESSAGE FOR WINDSHEAR AT THE ARPT WITH UP TO 15 KTS GAIN IN AIRSPD. AS I READ THE ACARS MESSAGE, AT ABOUT 4 MI ON FINAL AND 2100 FT MSL, THE TWR BROADCAST A MICROBURST ALERT FOR THE ARPT. AT THIS MOMENT WE COULD SEE THE TERRAIN AND THE APCH LIGHTS AHEAD, BUT COULD NOT SEE THE ARPT. THERE WAS A SHOWER MOVING OVER THE ARPT, BUT THE VISIBILITY ON FINAL APCH APPEARED TO BE ABOUT 3-4 MI. THE CONDITIONS BELOW US AND TO EACH SIDE WERE CLR. AT THE SAME TIME WE BEGAN TO EXPERIENCE A SLIGHT INCREASE IN TURB. AIRSPD FLUCTUATED -0 TO +15 KTS. THE IVSI NEEDLE INDICATED -300 FPM MOMENTARILY, THEN SWUNG TO -1500 FT. THE AUTOPLT WAS NOT KEEPING UP WITH THE CHANGES SO THE FO IMMEDIATELY DISCONNECTED IT AND BEGAN HAND-FLYING THE APCH. THE IVSI WAS CORRECTING TO ABOUT 800 FPM. ABOUT A HALF SECOND LATER, WE HEARD THE GPWS 'WHOOP, WHOOP, PULL UP.' THE FO IMMEDIATELY INITIATED A MISSED APCH. THE ENTIRE SEQUENCE FROM THE MICROBURST ALERT TO THE MISSED APCH TOOK ABOUT 2-3 SECONDS. THE FO AND I ADVANCED THE THRUST LEVERS TO THE GAR THRUST SETTING (NOT THE MECHANICAL STOPS) AND HE ROTATED TO THE GAR PITCH ATTITUDE OF 20 DEGS. DURING THE MISSED APCH, THE ACFT ACCELERATED AND CLBED NORMALLY AND WE NEVER SAW ANY EXCESSIVE LOSS OF AIRSPD OR ALT. WE NEVER RECEIVED ANY COCKPIT WINDSHEAR WARNING, AND THERE WAS NO STICK SHAKER OR BUFFET. WE CONTINUED THE MISSED APCH NORMALLY, RAISED THE GEAR AND FLAPS, AND SWITCHED TO APCH CTL AS INSTRUCTED BY TWR. THE SIT DETERIORATED QUICKLY FROM THE FAF TO THE POINT WHERE WE STARTED THE GAR. WE WERE BOTH CONSIDERING A GAR BUT DIDN'T HAVE TIME TO DISCUSS IT BEFORE WE RECEIVED THE GPWS WARNING. WE RECEIVED THE GPS WARNING AT ABOUT 1300 FT AGL. ALTHOUGH THE ARPT HAD A SHOWER DIRECTLY OVER IT, WE COULD CLRLY SEE THE TERRAIN AND THE APCH LIGHTS 3-4 MI AHEAD. THE MISSED APCH WAS CLRLY WARRANTED BY THE DETERIORATING CONDITIONS OVER THE ARPT. BUT THE GPWS MANEUVER WITH THRUST LEVERS AT THE STOPS SEEMED TO BE UNNECESSARY BASED ON OUR FLT CONDITIONS AND THE PERFORMANCE OF THE ACFT. I DID NOT SEE OR FEEL THE EXCESSIVE SINK RATE THAT SHOULD BE PRESENT IN ORDER TO CAUSE A MODE I GPWS WARNING. NEITHER DID THE FO. APCH CTL VECTORED US FOR A RADAR PATTERN TO A SECOND ILS APCH. AT LEAST ONE OTHER ACFT BEHIND US ALSO WENT MISSED APCH. ON DOWNWIND OF THE PATTERN, THE FO AND I DISCUSSED HOLDING TO WAIT UNTIL THE SHOWER CLRED THE ARPT. THE APCH CTLR INFORMED US THAT THE SHOWER WAS MOVING QUICKLY ACROSS THE FIELD AND WOULD PROBABLY BE CLR OF THE ARPT BEFORE WE GOT ON FINAL. WE CONTINUED THE PATTERN, AND THE FO FLEW AN UNEVENTFUL APCH AND LNDG. ON THE SECOND APCH, THE WX WAS ABOUT 1500 FT BROKEN AND 3 MI VISIBILITY.

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.