Narrative:

Morning flight pit-lex. Moderate turbulence on approach from about 5000 ft MSL down. Maneuvering to final approach we were getting plus or minus 10 KTS in light to moderate turbulence. Captain suggested 'we'll fly this approach a little fast,' for the turbulence. Contacting tower, we were given winds of 070 degrees at 20 KTS or so with peak gust of 30 KTS (which is within our crosswind limitations). At 500 ft we were at vref plus 20 on localizer and GS (autoplt off). Shortly thereafter, the f- 100's windshear warning activated and I instinctively advanced the throttles. The captain said 'we'll ignore that' and the approach was continued in VMC. The airplane's computers had entered the windshear recovery mode which displays escape guidance on the EFIS screens, dropping vref and bugged speed displays. Due to this lack of speed reference I believe we were a little fast on touchdown, maybe reference plus 12 or so, and within the first 2000 ft of the 7000 ft runway. The air/ground sensing system was not convinced we were on the ground. We rolled at least 2000 ft, unable to get brakes, reverse, or lift dumpers. The uphill slope and considerable headwind helped slow the airplane, and eventually (by 2000 ft from the end) the air/ground sensing allowed the brakes, etc to work. We were just about to switch off the anti-skid system, which is our emergency procedure for this situation, when things started working properly. Maybe we were hydroplaning on the water-soaked runway, we did touch down a little fast, but it was mainly an intentional act (slightly complicated by the loss of vref indication as a result of the windshear encounter). Had we gone off the end of the runway however, the decision to disregard the windshear warning would have been insupportable (now there's an understatement!) I personally believe the biggest issue here is this: if the airplane has a modern windshear warning system, either make it a policy to believe it and follow its guidance, or have very specific and widely understood criteria for disregarding it. If the 2 pilots have different plans when that warning sounds, it might lead to an unpleasant outcome. Callback conversation with reporter revealed the following information: the reporter stated the windshear logic triggers the warning. The pilot, then if he wants to, triggers the escape logic by application of power or toga. The landing speed guidance on the tape airspeed indicator disappears and the recommended speeds for the optimum windshear escape strategy appear. Simultaneously, the flight director discontinues the approach and landing guidance information logic and depicts the best pitch go around strategy for escaping the windshear. The problem occurs when the PF has elected to honor the windshear warning toga and the PNF subsequently determines the approach will be continued. The pilot is without even raw data airspeed information from the airspeed tape. Also, the pilot has conflicting flight director guidance. Pitch and power decisions in this already adverse WX situation become a seat of the pants, visual, activity. The pilot will not have the critical airspeed information short final, over the fence, and at touchdown. The reporter said he knew he was fast but had no idea how fast. He said the aircraft they were flying had the old ground sensing instead of the newer proximity switches. He doesn't know what prevented the spoilers from extending, brake application, and reverse application. It could have been failure of wheel spin up from hydroplaning or failure of ground sensing. Fortunately, lexington runway 04 is uphill. The captain may have had good reason for countermanding the go around. This event brought out how crucial it is for both pilots to agree ahead of time whether or not they plan to honor the windshear warning. The reporter believes the system is useful if both pilots agree to coordinate their decision ahead of time.

Related reports:

Google
 

Original NASA ASRS Text

Title: CAPT DIRECTS RPTR (FO) TO IGNORE WINDSHEAR WARNING, WINDSHEAR RECOVERY MODE, AND ESCAPE GUIDANCE AND CONTINUE FOR A LNDG.

Narrative: MORNING FLT PIT-LEX. MODERATE TURB ON APCH FROM ABOUT 5000 FT MSL DOWN. MANEUVERING TO FINAL APCH WE WERE GETTING PLUS OR MINUS 10 KTS IN LIGHT TO MODERATE TURB. CAPT SUGGESTED 'WE'LL FLY THIS APCH A LITTLE FAST,' FOR THE TURB. CONTACTING TWR, WE WERE GIVEN WINDS OF 070 DEGS AT 20 KTS OR SO WITH PEAK GUST OF 30 KTS (WHICH IS WITHIN OUR XWIND LIMITATIONS). AT 500 FT WE WERE AT VREF PLUS 20 ON LOC AND GS (AUTOPLT OFF). SHORTLY THEREAFTER, THE F- 100'S WINDSHEAR WARNING ACTIVATED AND I INSTINCTIVELY ADVANCED THE THROTTLES. THE CAPT SAID 'WE'LL IGNORE THAT' AND THE APCH WAS CONTINUED IN VMC. THE AIRPLANE'S COMPUTERS HAD ENTERED THE WINDSHEAR RECOVERY MODE WHICH DISPLAYS ESCAPE GUIDANCE ON THE EFIS SCREENS, DROPPING VREF AND BUGGED SPD DISPLAYS. DUE TO THIS LACK OF SPD REF I BELIEVE WE WERE A LITTLE FAST ON TOUCHDOWN, MAYBE REF PLUS 12 OR SO, AND WITHIN THE FIRST 2000 FT OF THE 7000 FT RWY. THE AIR/GND SENSING SYS WAS NOT CONVINCED WE WERE ON THE GND. WE ROLLED AT LEAST 2000 FT, UNABLE TO GET BRAKES, REVERSE, OR LIFT DUMPERS. THE UPHILL SLOPE AND CONSIDERABLE HEADWIND HELPED SLOW THE AIRPLANE, AND EVENTUALLY (BY 2000 FT FROM THE END) THE AIR/GND SENSING ALLOWED THE BRAKES, ETC TO WORK. WE WERE JUST ABOUT TO SWITCH OFF THE ANTI-SKID SYS, WHICH IS OUR EMER PROC FOR THIS SIT, WHEN THINGS STARTED WORKING PROPERLY. MAYBE WE WERE HYDROPLANING ON THE WATER-SOAKED RWY, WE DID TOUCH DOWN A LITTLE FAST, BUT IT WAS MAINLY AN INTENTIONAL ACT (SLIGHTLY COMPLICATED BY THE LOSS OF VREF INDICATION AS A RESULT OF THE WINDSHEAR ENCOUNTER). HAD WE GONE OFF THE END OF THE RWY HOWEVER, THE DECISION TO DISREGARD THE WINDSHEAR WARNING WOULD HAVE BEEN INSUPPORTABLE (NOW THERE'S AN UNDERSTATEMENT!) I PERSONALLY BELIEVE THE BIGGEST ISSUE HERE IS THIS: IF THE AIRPLANE HAS A MODERN WINDSHEAR WARNING SYS, EITHER MAKE IT A POLICY TO BELIEVE IT AND FOLLOW ITS GUIDANCE, OR HAVE VERY SPECIFIC AND WIDELY UNDERSTOOD CRITERIA FOR DISREGARDING IT. IF THE 2 PLTS HAVE DIFFERENT PLANS WHEN THAT WARNING SOUNDS, IT MIGHT LEAD TO AN UNPLEASANT OUTCOME. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE WINDSHEAR LOGIC TRIGGERS THE WARNING. THE PLT, THEN IF HE WANTS TO, TRIGGERS THE ESCAPE LOGIC BY APPLICATION OF PWR OR TOGA. THE LNDG SPD GUIDANCE ON THE TAPE AIRSPD INDICATOR DISAPPEARS AND THE RECOMMENDED SPDS FOR THE OPTIMUM WINDSHEAR ESCAPE STRATEGY APPEAR. SIMULTANEOUSLY, THE FLT DIRECTOR DISCONTINUES THE APCH AND LNDG GUIDANCE INFO LOGIC AND DEPICTS THE BEST PITCH GAR STRATEGY FOR ESCAPING THE WINDSHEAR. THE PROB OCCURS WHEN THE PF HAS ELECTED TO HONOR THE WINDSHEAR WARNING TOGA AND THE PNF SUBSEQUENTLY DETERMINES THE APCH WILL BE CONTINUED. THE PLT IS WITHOUT EVEN RAW DATA AIRSPD INFO FROM THE AIRSPD TAPE. ALSO, THE PLT HAS CONFLICTING FLT DIRECTOR GUIDANCE. PITCH AND PWR DECISIONS IN THIS ALREADY ADVERSE WX SIT BECOME A SEAT OF THE PANTS, VISUAL, ACTIVITY. THE PLT WILL NOT HAVE THE CRITICAL AIRSPD INFO SHORT FINAL, OVER THE FENCE, AND AT TOUCHDOWN. THE RPTR SAID HE KNEW HE WAS FAST BUT HAD NO IDEA HOW FAST. HE SAID THE ACFT THEY WERE FLYING HAD THE OLD GND SENSING INSTEAD OF THE NEWER PROX SWITCHES. HE DOESN'T KNOW WHAT PREVENTED THE SPOILERS FROM EXTENDING, BRAKE APPLICATION, AND REVERSE APPLICATION. IT COULD HAVE BEEN FAILURE OF WHEEL SPIN UP FROM HYDROPLANING OR FAILURE OF GND SENSING. FORTUNATELY, LEXINGTON RWY 04 IS UPHILL. THE CAPT MAY HAVE HAD GOOD REASON FOR COUNTERMANDING THE GAR. THIS EVENT BROUGHT OUT HOW CRUCIAL IT IS FOR BOTH PLTS TO AGREE AHEAD OF TIME WHETHER OR NOT THEY PLAN TO HONOR THE WINDSHEAR WARNING. THE RPTR BELIEVES THE SYS IS USEFUL IF BOTH PLTS AGREE TO COORDINATE THEIR DECISION AHEAD OF 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.