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An air carrier pilot on an oceanic non-radar track at FL350 used his emergency authority to deviate 6 NM off course for thunderstorms.
| Attributes | |
| ACN | 780399 |
| Time | |
| Date | 200803 |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : zzz.artcc |
| State Reference | US |
| Altitude | msl single value : 35000 |
| Environment | |
| Flight Conditions | VMC |
| Weather Elements | Thunderstorm |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zzz.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B757-200 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Route In Use | enroute : other oceanic |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| ASRS Report | 780399 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| ASRS Report | 780833 |
| Events | |
| Anomaly | other spatial deviation |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : exited adverse environment flight crew : returned to intended or assigned course |
| Supplementary | |
| Problem Areas | ATC Human Performance Weather |
| Primary Problem | Weather |
Narrative:
A line of thunderstorms (part of an issued convective SIGMET) crossed our route of flight about 20 NM north of xxxxx. About 90 NM prior to this WX; a deviation up to 25 NM right (west and upwind) of course was requested from ATC via commercial radio. About 5 mins later the request was repeated. Eventually the request was denied and I was asked to state my intentions from the person sitting safely on the ground; not: 'ATC can approve 15 mi left or 20 mi right' for example. I immediately requested 10 mi left deviation and added that I needed the clearance within 3 mins for a thunderstorm ahead. When I could wait no longer for the clearance; I informed ATC I was going to deviate up to 10 mi left of course to avoid the thunderstorm (exercising captain's emergency authority/authorized). The maximum deviation was 6 mi left of course; we monitored TCAS; kept a visual lookout; and the aircraft was back on course by xxxxx. ATC was notified.
Original NASA ASRS Text
Title: AN ACR PILOT ON AN OCEANIC NON-RADAR TRACK AT FL350 USED HIS EMER AUTHORITY TO DEVIATE 6 NM OFF COURSE FOR TSTMS.
Narrative: A LINE OF TSTMS (PART OF AN ISSUED CONVECTIVE SIGMET) CROSSED OUR RTE OF FLT ABOUT 20 NM N OF XXXXX. ABOUT 90 NM PRIOR TO THIS WX; A DEV UP TO 25 NM R (W AND UPWIND) OF COURSE WAS REQUESTED FROM ATC VIA COMMERCIAL RADIO. ABOUT 5 MINS LATER THE REQUEST WAS REPEATED. EVENTUALLY THE REQUEST WAS DENIED AND I WAS ASKED TO STATE MY INTENTIONS FROM THE PERSON SITTING SAFELY ON THE GND; NOT: 'ATC CAN APPROVE 15 MI L OR 20 MI R' FOR EXAMPLE. I IMMEDIATELY REQUESTED 10 MI L DEV AND ADDED THAT I NEEDED THE CLRNC WITHIN 3 MINS FOR A TSTM AHEAD. WHEN I COULD WAIT NO LONGER FOR THE CLRNC; I INFORMED ATC I WAS GOING TO DEVIATE UP TO 10 MI L OF COURSE TO AVOID THE TSTM (EXERCISING CAPT'S EMER AUTH). THE MAX DEV WAS 6 MI L OF COURSE; WE MONITORED TCAS; KEPT A VISUAL LOOKOUT; AND THE ACFT WAS BACK ON COURSE BY XXXXX. ATC WAS NOTIFIED.
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.