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An air carrier captain experiences a runway awareness and advisory system (raas) warning 'on taxiway on taxiway' while attempting to takeoff on runway 23L at rctp from the S10 taxiway. The warning is ignored as the runway has a displaced threshold for landing that does not apply to aircraft taking off.
| Attributes | |
| ACN | 1264403 |
| Time | |
| Date | 201505 |
| Local Time Of Day | 1801-2400 |
| Place | |
| Locale Reference | RCTP.Airport |
| State Reference | FO |
| Aircraft 1 | |
| Make Model Name | Widebody Transport |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Takeoff |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | GPWS |
| Person 1 | |
| Function | Captain Check Pilot |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Ground Incursion Taxiway |
Narrative:
We were cleared to taxi 23L holding point; which is S10; the end of the runway. We were then cleared to line up and wait on the runway. When we were cleared for takeoff; the captain advanced the power and runway awareness and advisory system (raas) advised 'on taxiway on taxiway'. We were not on the taxiway so take off was continued normally. As we approached S9 (the displaced threshold) raas then said approaching runway 23L! There is a displaced landing threshold; but not for takeoff. So raas/egpws database may be incorrect for this runway. I have never heard that before utilizing any other displaced threshold for takeoff!possible bad programming in the raas. If it is programmed correctly; then crews need to be aware they will receive the warning because it is very disconcerting; even in VMC. Imagine doing a low visibility takeoff and having this occur! Fix raas so that it doesn't nuisance alert thinking the runway is the taxiway! Or alert the crews so they know what to expect. Or disable raas until it's fixed!
Original NASA ASRS Text
Title: An Air Carrier Captain experiences a Runway Awareness and Advisory System (RAAS) warning 'ON TAXIWAY ON TAXIWAY' while attempting to takeoff on Runway 23L at RCTP from the S10 taxiway. The warning is ignored as the runway has a displaced threshold for landing that does not apply to aircraft taking off.
Narrative: We were cleared to taxi 23L holding point; which is S10; the end of the runway. We were then cleared to line up and wait on the runway. When we were cleared for takeoff; the Captain advanced the power and Runway awareness and Advisory System (RAAS) advised 'ON TAXIWAY ON TAXIWAY'. We were not on the taxiway so take off was continued normally. As we approached S9 (the displaced threshold) RAAS then said approaching RWY 23L! There is a displaced LANDING THRESHOLD; but not for takeoff. So RAAS/EGPWS database may be incorrect for this runway. I have never heard that before utilizing any other displaced threshold for takeoff!Possible bad programming in the RAAS. If it is programmed correctly; then crews need to be aware they will receive the warning because it is very disconcerting; even in VMC. Imagine doing a low visibility takeoff and having this occur! Fix RAAS so that it doesn't nuisance alert thinking the runway is the taxiway! Or alert the crews so they know what to expect. Or disable RAAS until it's fixed!
Data retrieved from NASA's ASRS site 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.