Narrative:

WX: hong kong. ATIS: 060-110 10g20 peak gust 30 9 KM. Wind given by tower at start of takeoff 080-120/10g20. Gross weight: at takeoff 700000#. Description of occurrence: while taxiing out to runway 13, the first officer and I talked over the departure altitudes, headings, and etc. When the second officer passed the takeoff numbers up, I questioned level 1 power and he said I had a 50000 pounds pad on level 1 and 20000# for level 2. I decided that level 1 with a 50000 pounds pad would be sufficient power for the WX conditions. Previously, I had asked the first officer how much experience he had on the widebody transport. He responded that he had flown the aircraft for 12 yrs as copilot. With this much experience on the aircraft I decided to let him make the takeoff. It was a normal takeoff roll until we started rotation. The aircraft felt like it just lifted off the runway, when got a momentary stick shaker. The first officer then stopped the rotation. The airspeed was well above marked bug. The first officer started rotation again and got another momentary stick shaker. The airspeed was still above the marked bug. After this, the aircraft climbed out normally. We never felt or suspected a tail strike and no one reported to us that the tail hit the runway on takeoff. The second officer was monitoring #3 INS for windshear during takeoff and reported no indication of windshear on the INS. The remainder of the flight to narita was normal until parked at narita. Maintenance then noticed damage to the skin on the bottom of the tail. I know that the second officer had numerous yrs experience on the widebody transport as a copilot and is presently a second officer instrument in the training department. Therefore, I felt no need to further question the 50000 pounds pad for level 1 power which he stated we had. After informed of the tail strike we checked the power chart and found the second officer had used the wrong chart and instead of 50000 pounds pad we only had 12000 pounds. If I would have known this, I would have used full power with the gusty winds.

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Original NASA ASRS Text

Title: FLC OF WDB USED REDUCED THRUST FOR TKOF IN GUSTY WIND CONDITIONS. EXPERIENCED TWO STALL WARNINGS AFTER ROTATION. SO HAD PROVIDED ERRONEOUS TKOF DATA.

Narrative: WX: HONG KONG. ATIS: 060-110 10G20 PEAK GUST 30 9 KM. WIND GIVEN BY TWR AT START OF TKOF 080-120/10G20. GROSS WEIGHT: AT TKOF 700000#. DESCRIPTION OF OCCURRENCE: WHILE TAXIING OUT TO RWY 13, THE F/O AND I TALKED OVER THE DEP ALTS, HDGS, AND ETC. WHEN THE S/O PASSED THE TKOF NUMBERS UP, I QUESTIONED LEVEL 1 PWR AND HE SAID I HAD A 50000 LBS PAD ON LEVEL 1 AND 20000# FOR LEVEL 2. I DECIDED THAT LEVEL 1 WITH A 50000 LBS PAD WOULD BE SUFFICIENT PWR FOR THE WX CONDITIONS. PREVIOUSLY, I HAD ASKED THE F/O HOW MUCH EXPERIENCE HE HAD ON THE WDB. HE RESPONDED THAT HE HAD FLOWN THE ACFT FOR 12 YRS AS COPLT. WITH THIS MUCH EXPERIENCE ON THE ACFT I DECIDED TO LET HIM MAKE THE TKOF. IT WAS A NORMAL TKOF ROLL UNTIL WE STARTED ROTATION. THE ACFT FELT LIKE IT JUST LIFTED OFF THE RWY, WHEN GOT A MOMENTARY STICK SHAKER. THE F/O THEN STOPPED THE ROTATION. THE AIRSPD WAS WELL ABOVE MARKED BUG. THE F/O STARTED ROTATION AGAIN AND GOT ANOTHER MOMENTARY STICK SHAKER. THE AIRSPD WAS STILL ABOVE THE MARKED BUG. AFTER THIS, THE ACFT CLBED OUT NORMALLY. WE NEVER FELT OR SUSPECTED A TAIL STRIKE AND NO ONE RPTED TO US THAT THE TAIL HIT THE RWY ON TKOF. THE S/O WAS MONITORING #3 INS FOR WINDSHEAR DURING TKOF AND RPTED NO INDICATION OF WINDSHEAR ON THE INS. THE REMAINDER OF THE FLT TO NARITA WAS NORMAL UNTIL PARKED AT NARITA. MAINT THEN NOTICED DAMAGE TO THE SKIN ON THE BOTTOM OF THE TAIL. I KNOW THAT THE S/O HAD NUMEROUS YRS EXPERIENCE ON THE WDB AS A COPLT AND IS PRESENTLY A S/O INSTR IN THE TRNING DEPT. THEREFORE, I FELT NO NEED TO FURTHER QUESTION THE 50000 LBS PAD FOR LEVEL 1 PWR WHICH HE STATED WE HAD. AFTER INFORMED OF THE TAIL STRIKE WE CHKED THE PWR CHART AND FOUND THE S/O HAD USED THE WRONG CHART AND INSTEAD OF 50000 LBS PAD WE ONLY HAD 12000 LBS. IF I WOULD HAVE KNOWN THIS, I WOULD HAVE USED FULL PWR WITH THE GUSTY WINDS.

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.