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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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B757-200 flight crew en route to lax offsets route to eliminate nuisance GPWS warnings from aircraft 1000 ft below. Unreported speed increase to gain separation prior to the mainland is questioned by ATC.
| Attributes | |
| ACN | 727193 |
| Time | |
| Date | 200702 |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : zla.artcc |
| State Reference | CA |
| Altitude | msl single value : 37000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : zla.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B757-200 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : level |
| Route In Use | enroute : other oceanic |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zla.artcc |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Flight Phase | cruise : level |
| Route In Use | enroute : other oceanic |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| ASRS Report | 727193 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| ASRS Report | 727196 |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : published procedure non adherence : clearance non adherence : far other anomaly |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued advisory |
| Consequence | faa : reviewed incident with flight crew |
| Supplementary | |
| Problem Areas | Airspace Structure Flight Crew Human Performance Aircraft |
| Primary Problem | Airspace Structure |
Narrative:
While in cruise at FL370 mach 78 as filed approximately 40 miles from edsel intersection on the 'echo' track from kahului we got an aural warning 'terrain; too low; pull up' and the RA was bouncing from no report to just under 1000 ft. Quickly rechecking our altitude which showed exactly FL370 on the captain and 36990 ft on the first officer altimeters. We immediately dropped our eyes to the TCAS. There was an aircraft directly below us. The warnings continued on and off every 10 seconds or so for the next several mins. We then decided to offset the track by 1 mile to gain separation. This solved the problem. Knowing that we would have to return to track prior to reaching edsel we decided to speed up to gain some separation. We accelerated to mach 82 about 20 miles prior and with some separation showing on the TCAS we returned to track. We decided to call ATC los angeles center approaching edsel early to account for the change in speed. This we did about 13 to 14 miles prior. Upon contact he assigned us a squawk and once radar identified his first question to us was what was our speed. We reported the increase to mach 82. The increase in speed actually occurred on the oceanic track but it seemed prudent to wait the 1 to 2 mins until reaching la center rather than trying to get a clearance over HF. The increase in speed was also less than the 5 percent TAS which requires a report to non oceanic controlling airspace.
Original NASA ASRS Text
Title: B757-200 FLT CREW ENRTE TO LAX OFFSETS RTE TO ELIMINATE NUISANCE GPWS WARNINGS FROM ACFT 1000 FT BELOW. UNREPORTED SPEED INCREASE TO GAIN SEPARATION PRIOR TO THE MAINLAND IS QUESTIONED BY ATC.
Narrative: WHILE IN CRUISE AT FL370 MACH 78 AS FILED APPROX 40 MILES FROM EDSEL INTXN ON THE 'ECHO' TRACK FROM KAHULUI WE GOT AN AURAL WARNING 'TERRAIN; TOO LOW; PULL UP' AND THE RA WAS BOUNCING FROM NO RPT TO JUST UNDER 1000 FT. QUICKLY RECHECKING OUR ALT WHICH SHOWED EXACTLY FL370 ON THE CAPT AND 36990 FT ON THE FO ALTIMETERS. WE IMMEDIATELY DROPPED OUR EYES TO THE TCAS. THERE WAS AN ACFT DIRECTLY BELOW US. THE WARNINGS CONTINUED ON AND OFF EVERY 10 SECONDS OR SO FOR THE NEXT SEVERAL MINS. WE THEN DECIDED TO OFFSET THE TRACK BY 1 MILE TO GAIN SEPARATION. THIS SOLVED THE PROB. KNOWING THAT WE WOULD HAVE TO RETURN TO TRACK PRIOR TO REACHING EDSEL WE DECIDED TO SPEED UP TO GAIN SOME SEPARATION. WE ACCELERATED TO MACH 82 ABOUT 20 MILES PRIOR AND WITH SOME SEPARATION SHOWING ON THE TCAS WE RETURNED TO TRACK. WE DECIDED TO CALL ATC LOS ANGELES CENTER APCHING EDSEL EARLY TO ACCOUNT FOR THE CHANGE IN SPEED. THIS WE DID ABOUT 13 TO 14 MILES PRIOR. UPON CONTACT HE ASSIGNED US A SQUAWK AND ONCE RADAR IDENTIFIED HIS FIRST QUESTION TO US WAS WHAT WAS OUR SPEED. WE RPTED THE INCREASE TO MACH 82. THE INCREASE IN SPEED ACTUALLY OCCURRED ON THE OCEANIC TRACK BUT IT SEEMED PRUDENT TO WAIT THE 1 TO 2 MINS UNTIL REACHING LA CENTER RATHER THAN TRYING TO GET A CLRNC OVER HF. THE INCREASE IN SPEED WAS ALSO LESS THAN THE 5 PERCENT TAS WHICH REQUIRES A RPT TO NON OCEANIC CONTROLLING AIRSPACE.
Data retrieved from NASA's ASRS site as of January 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.