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Flight crew and dispatcher question MEL limitation on Q400 with both GPS systems deferred inoperative.
| Attributes | |
| ACN | 656128 |
| Time | |
| Date | 200504 |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : pdx.airport |
| State Reference | OR |
| Altitude | agl single value : 0 |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | Dash 8-400 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | ground : preflight |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | other personnel |
| ASRS Report | 656128 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Events | |
| Anomaly | aircraft equipment problem : critical non adherence other |
| Independent Detector | other flight crewa |
| Resolutory Action | other |
| Consequence | other |
| Supplementary | |
| Problem Areas | Company Chart Or Publication Aircraft Flight Crew Human Performance |
| Primary Problem | Chart Or Publication |
| Situations | |
| Chart | airport : pdx.airport sid : crown |
Narrative:
Just before departure time; crew calls with question regarding crown one RNAV departure out of portland. Crown one RNAV departure is the default departure out of portland and was the filed departure on their flight plan. Aircraft had both captain and first officer GPS sensors inoperative rendering the GPS inoperative. The sensors were deferred under MEL; which states only that FMS based apches and terminal NAVAID substitutions prohibited. The crew's concern was that there's no mention of RNAV departures listed in the MEL. The departure states that 'GPS required' and MEL states 'GPS deselected on affected FMS' so captain and dispatcher concurred that RNAV departures are prohibited as well. Both crew and dispatcher would like to see MEL revised to include RNAV departures listed under operating procedures as prohibiting actions. Callback conversation with reporter revealed the following information: the company advised the reporter they are looking into this issue. In the instant case the ultimate decision was to simply refile via a conventional departure and; as a /a equipment type; fly the entire segment by appropriate /a navaids.
Original NASA ASRS Text
Title: FLT CREW AND DISPATCHER QUESTION MEL LIMITATION ON Q400 WITH BOTH GPS SYSTEMS DEFERRED INOP.
Narrative: JUST BEFORE DEP TIME; CREW CALLS WITH QUESTION REGARDING CROWN ONE RNAV DEP OUT OF PORTLAND. CROWN ONE RNAV DEP IS THE DEFAULT DEP OUT OF PORTLAND AND WAS THE FILED DEP ON THEIR FLT PLAN. ACFT HAD BOTH CAPT AND FO GPS SENSORS INOP RENDERING THE GPS INOP. THE SENSORS WERE DEFERRED UNDER MEL; WHICH STATES ONLY THAT FMS BASED APCHES AND TERMINAL NAVAID SUBSTITUTIONS PROHIBITED. THE CREW'S CONCERN WAS THAT THERE'S NO MENTION OF RNAV DEPS LISTED IN THE MEL. THE DEP STATES THAT 'GPS REQUIRED' AND MEL STATES 'GPS DESELECTED ON AFFECTED FMS' SO CAPT AND DISPATCHER CONCURRED THAT RNAV DEPS ARE PROHIBITED AS WELL. BOTH CREW AND DISPATCHER WOULD LIKE TO SEE MEL REVISED TO INCLUDE RNAV DEPS LISTED UNDER OPERATING PROCS AS PROHIBITING ACTIONS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE COMPANY ADVISED THE RPTR THEY ARE LOOKING INTO THIS ISSUE. IN THE INSTANT CASE THE ULTIMATE DECISION WAS TO SIMPLY REFILE VIA A CONVENTIONAL DEP AND; AS A /A EQUIP TYPE; FLY THE ENTIRE SEGMENT BY APPROPRIATE /A NAVAIDS.
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.