|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1201 To 1800|
|Locale Reference||airport : anc|
|Altitude||agl bound lower : 0|
agl bound upper : 0
|Operator||common carrier : air carrier|
|Make Model Name||Medium Large Transport, Low Wing, 2 Turbojet Eng|
|Flight Phase||climbout : takeoff|
|Affiliation||company : air carrier|
|Function||flight crew : captain|
oversight : pic
|Qualification||pilot : flight engineer|
pilot : instrument
pilot : atp
|Experience||flight time last 90 days : 120|
flight time total : 9800
flight time type : 5800
|Affiliation||company : air carrier|
|Function||flight crew : first officer|
|Qualification||pilot : instrument|
pilot : commercial
|Anomaly||other anomaly other|
|Independent Detector||aircraft equipment other aircraft equipment : unspecified|
other flight crewa
|Resolutory Action||flight crew : rejected takeoff|
|Air Traffic Incident||other|
|ATC Facility||other physical facility|
High speed abort runway 32, anchorage IAP, medium large transport. ATIS reported winds 270/6. Matched takeoff wind just prior to departure roll. Aircraft accelerated slightly slower than normal, but not unusually slow (spring temperatures). At 80 KIAS, airspeed momentarily hesitated, then continued to climb. At 120 KIAS, airspeed stagnated for approximately 1000 ft of takeoff roll. I suspected a wind shear condition and considered an abort, when the airspeed began to increase again. V-spds were V1-148, vr-150, V2-157 for flaps 1. At approximately 140 KIAS, airspeed abruptly decreased by 15 KIAS and was nearly 1000 ft beyond my normal rotation point for this gross weight. I had nearly 4000 ft remaining runway and was confident I could stop the aircraft in the remaining runway, but was not confident that should I continue the takeoff, that possibly stronger tailwinds during second segment were absent. Therefore, I aborted using established company procedures. Tower notified, cleared the runway. Airport safety visually checked for tire damage or fire. None noted, taxied to gate. 3 tires were later changed for suspected fuse plug overtemp and 1 brake changed due to wear beyond limits. As we taxied back, noted that windsock was indicating a strong south wind. Recommended to tower no more departures on runway 32 due to wind shear. Next aircraft on runway 24 noted a 15 KT airspeed loss after takeoff. I don't know what would have happened after we had taken off, but I can say that excellent company simulator wind shear training paid off. Abort was exciting, but 'automatic.' first officer remarked, 'I have never seen the airspeed do that on runway 32.' that's why we aborted, neither had I with nearly 2000 takeoffs in various aircraft from that runway. No virga or low-level wind shear had been reported. It just seemed to be a sudden change in wind speed and direction. Dry runway.
Original NASA ASRS Text
Title: AN ACR MLG MADE A HIGH SPD ABORT DUE TO UNRPTED WIND SHEAR.
Narrative: HIGH SPD ABORT RWY 32, ANCHORAGE IAP, MLG. ATIS RPTED WINDS 270/6. MATCHED TKOF WIND JUST PRIOR TO DEP ROLL. ACFT ACCELERATED SLIGHTLY SLOWER THAN NORMAL, BUT NOT UNUSUALLY SLOW (SPRING TEMPS). AT 80 KIAS, AIRSPD MOMENTARILY HESITATED, THEN CONTINUED TO CLB. AT 120 KIAS, AIRSPD STAGNATED FOR APPROX 1000 FT OF TKOF ROLL. I SUSPECTED A WIND SHEAR CONDITION AND CONSIDERED AN ABORT, WHEN THE AIRSPD BEGAN TO INCREASE AGAIN. V-SPDS WERE V1-148, VR-150, V2-157 FOR FLAPS 1. AT APPROX 140 KIAS, AIRSPD ABRUPTLY DECREASED BY 15 KIAS AND WAS NEARLY 1000 FT BEYOND MY NORMAL ROTATION POINT FOR THIS GROSS WT. I HAD NEARLY 4000 FT REMAINING RWY AND WAS CONFIDENT I COULD STOP THE ACFT IN THE REMAINING RWY, BUT WAS NOT CONFIDENT THAT SHOULD I CONTINUE THE TKOF, THAT POSSIBLY STRONGER TAILWINDS DURING SECOND SEGMENT WERE ABSENT. THEREFORE, I ABORTED USING ESTABLISHED COMPANY PROCS. TWR NOTIFIED, CLRED THE RWY. ARPT SAFETY VISUALLY CHKED FOR TIRE DAMAGE OR FIRE. NONE NOTED, TAXIED TO GATE. 3 TIRES WERE LATER CHANGED FOR SUSPECTED FUSE PLUG OVERTEMP AND 1 BRAKE CHANGED DUE TO WEAR BEYOND LIMITS. AS WE TAXIED BACK, NOTED THAT WINDSOCK WAS INDICATING A STRONG S WIND. RECOMMENDED TO TWR NO MORE DEPS ON RWY 32 DUE TO WIND SHEAR. NEXT ACFT ON RWY 24 NOTED A 15 KT AIRSPD LOSS AFTER TKOF. I DON'T KNOW WHAT WOULD HAVE HAPPENED AFTER WE HAD TAKEN OFF, BUT I CAN SAY THAT EXCELLENT COMPANY SIMULATOR WIND SHEAR TRAINING PAID OFF. ABORT WAS EXCITING, BUT 'AUTOMATIC.' FO REMARKED, 'I HAVE NEVER SEEN THE AIRSPD DO THAT ON RWY 32.' THAT'S WHY WE ABORTED, NEITHER HAD I WITH NEARLY 2000 TKOFS IN VARIOUS ACFT FROM THAT RWY. NO VIRGA OR LOW-LEVEL WIND SHEAR HAD BEEN RPTED. IT JUST SEEMED TO BE A SUDDEN CHANGE IN WIND SPD AND DIRECTION. DRY RWY.
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.