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A B737 flight noticed while accelerating through 100 KTS on takeoff, that the airspeed was then slow to increase.
| Attributes | |
| ACN | 619615 |
| Time | |
| Date | 200405 |
| Day | Fri |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : cle.airport |
| State Reference | OH |
| Altitude | agl single value : 0 |
| Environment | |
| Flight Conditions | VMC |
| Weather Elements | Thunderstorm Windshear other |
| Light | Daylight |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B737 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | climbout : takeoff ground : takeoff roll |
| Flight Plan | None |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument pilot : multi engine |
| Experience | flight time total : 10000 flight time type : 4000 |
| ASRS Report | 619615 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 250 flight time total : 30000 flight time type : 8000 |
| ASRS Report | 619617 |
| Events | |
| Anomaly | inflight encounter : weather inflight encounter other other anomaly other anomaly other other anomaly other |
| Independent Detector | other flight crewa other flight crewb |
| Resolutory Action | none taken : anomaly accepted |
| Consequence | Other |
| Supplementary | |
| Problem Areas | Aircraft Environmental Factor Flight Crew Human Performance Weather |
| Primary Problem | Weather |
Narrative:
Line of thunderstorms approximately 5 mi away approaching airport from southwest. Cleared for takeoff on runway 6C. Acceleration through 100 KTS normal, then noticed airspeed fluctuations and failure to accelerate normally going through approximately 110 KTS. Airspeed was still slowly accelerating toward V1, but erratically. No GPWS warnings of windshear or anything else. PF rotated at vr to vr+5 KTS, but had used up most of runway. We had a very high ground speed at this point. Winds at toga (at application of takeoff thrust) were reported as a quartering headwind at 4 KTS. 1 min after takeoff, wind reported at 290 degrees at 44 KTS with higher gusts, resulting in a 30+ KT component tailwind. As PNF, I did not report airspeed variations above 100 KTS since trained to only call 'power loss.' assumed (correctly) that PF knew of airspeed fluctuations.
Original NASA ASRS Text
Title: A B737 FLT NOTICED WHILE ACCELERATING THROUGH 100 KTS ON TKOF, THAT THE AIRSPD WAS THEN SLOW TO INCREASE.
Narrative: LINE OF TSTMS APPROX 5 MI AWAY APCHING ARPT FROM SW. CLRED FOR TKOF ON RWY 6C. ACCELERATION THROUGH 100 KTS NORMAL, THEN NOTICED AIRSPD FLUCTUATIONS AND FAILURE TO ACCELERATE NORMALLY GOING THROUGH APPROX 110 KTS. AIRSPD WAS STILL SLOWLY ACCELERATING TOWARD V1, BUT ERRATICALLY. NO GPWS WARNINGS OF WINDSHEAR OR ANYTHING ELSE. PF ROTATED AT VR TO VR+5 KTS, BUT HAD USED UP MOST OF RWY. WE HAD A VERY HIGH GND SPD AT THIS POINT. WINDS AT TOGA (AT APPLICATION OF TKOF THRUST) WERE RPTED AS A QUARTERING HEADWIND AT 4 KTS. 1 MIN AFTER TKOF, WIND RPTED AT 290 DEGS AT 44 KTS WITH HIGHER GUSTS, RESULTING IN A 30+ KT COMPONENT TAILWIND. AS PNF, I DID NOT RPT AIRSPD VARIATIONS ABOVE 100 KTS SINCE TRAINED TO ONLY CALL 'PWR LOSS.' ASSUMED (CORRECTLY) THAT PF KNEW OF AIRSPD FLUCTUATIONS.
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.