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B747-400 captain advises unable to access full length of runway 10L from S2 taxiway at sfo. Believes reduced thrust computations based on full length are not accurate.
| Attributes | |
| ACN | 771805 |
| Time | |
| Date | 200801 |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : sfo.airport |
| State Reference | CA |
| Altitude | agl single value : 0 |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B747-400 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | ground : taxi |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain observation : company check pilot oversight : pic |
| Experience | flight time last 90 days : 60 flight time total : 15000 flight time type : 2000 |
| ASRS Report | 771805 |
| Events | |
| Anomaly | non adherence : company policies non adherence : published procedure non adherence : far |
| Independent Detector | other flight crewa |
| Resolutory Action | none taken : anomaly accepted |
| Consequence | other |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance Company Chart Or Publication Airport Aircraft |
| Primary Problem | Ambiguous |
Narrative:
There is a potential problem with the use of taxiway S2 to enter sfo runway 10L for takeoff. The westernmost portion of the bulbous area of S-S2 just to the south of runway 10L is not available for taxi. Therefore; the closest a B747-400 can get to the end of the runway for takeoff line-up is approximately 500 ft down the runway. We have takeoff data available from the full length of runway 10L and from taxiway U with 10840 ft available; but none from 500 ft down the runway. When a fully loaded B747-400 takes off it would be prudent to know if there was any difference in the runway performance data at these 3 points. Access from taxiway south from the north or the south to runway 10L allows full length use and taxiway U has specific data; but none was available for entry from taxiway S2. The reporter advised they utilized maximum takeoff thrust for their departure vice the normal reduced figure based; they believed; on the full length of the runway. His air carrier's tech specialists have since advised they were aware of the problem and that a point down the runway had been established for all takeoff computations from 10L.
Original NASA ASRS Text
Title: B747-400 CAPTAIN ADVISES UNABLE TO ACCESS FULL LENGTH OF RWY 10L FROM S2 TXWY AT SFO. BELIEVES REDUCED THRUST COMPUTATIONS BASED ON FULL LENGTH ARE NOT ACCURATE.
Narrative: THERE IS A POTENTIAL PROB WITH THE USE OF TXWY S2 TO ENTER SFO RWY 10L FOR TKOF. THE WESTERNMOST PORTION OF THE BULBOUS AREA OF S-S2 JUST TO THE S OF RWY 10L IS NOT AVAILABLE FOR TAXI. THEREFORE; THE CLOSEST A B747-400 CAN GET TO THE END OF THE RWY FOR TKOF LINE-UP IS APPROX 500 FT DOWN THE RWY. WE HAVE TKOF DATA AVAILABLE FROM THE FULL LENGTH OF RWY 10L AND FROM TXWY U WITH 10840 FT AVAILABLE; BUT NONE FROM 500 FT DOWN THE RWY. WHEN A FULLY LOADED B747-400 TAKES OFF IT WOULD BE PRUDENT TO KNOW IF THERE WAS ANY DIFFERENCE IN THE RWY PERFORMANCE DATA AT THESE 3 POINTS. ACCESS FROM TXWY S FROM THE N OR THE S TO RWY 10L ALLOWS FULL LENGTH USE AND TXWY U HAS SPECIFIC DATA; BUT NONE WAS AVAILABLE FOR ENTRY FROM TXWY S2. THE REPORTER ADVISED THEY UTILIZED MAX TKOF THRUST FOR THEIR DEPARTURE VICE THE NORMAL REDUCED FIGURE BASED; THEY BELIEVED; ON THE FULL LENGTH OF THE RWY. HIS ACR'S TECH SPECIALISTS HAVE SINCE ADVISED THEY WERE AWARE OF THE PROBLEM AND THAT A POINT DOWN THE RWY HAD BEEN ESTABLISHED FOR ALL TKOF COMPUTATIONS FROM 10L.
Data retrieved from NASA's ASRS site as of May 2009 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.