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An LJ60 pilot reports aircraft's inability to maintain rvsm requirement in mountain wave action and receiving block altitude clrncs.
| Attributes | |
| ACN | 689477 |
| Time | |
| Date | 200602 |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : pub.airport |
| State Reference | CO |
| Altitude | msl bound lower : 39000 msl bound upper : 43000 |
| Environment | |
| Flight Conditions | VMC |
| Weather Elements | Turbulence |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zdv.artcc tower : zzz.tower |
| Operator | general aviation : corporate |
| Make Model Name | Learjet 60 |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | other |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : corporate |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 10 flight time total : 13300 flight time type : 1800 |
| ASRS Report | 689477 |
| Person 2 | |
| Affiliation | company : corporate |
| Function | flight crew : first officer |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude inflight encounter other non adherence : clearance |
| Independent Detector | other flight crewa |
| Resolutory Action | controller : issued new clearance flight crew : exited adverse environment |
| Consequence | faa : reviewed incident with flight crew |
| Supplementary | |
| Problem Areas | Aircraft Environmental Factor |
| Primary Problem | Environmental Factor |
Narrative:
Moderate mountain wave was encountered and a block altitude FL400-FL430 was requested and approved. In the block 500 ft deviations at .04 mi airspeed fluctuations occurred even with full and idle power inputs. The altitude excursions were necessary to stay below mmo and above the minimum safe speed. A lower block FL380-FL400 was requested. Center assigned FL390 where the altitude excursions were +/-170 ft. The block FL390-FL410 was finally assigned when I advised center that if my flight didn't get a block altitude I would have to declare 'unable rvsm due to mountain wave.' prompt communication and coordination allowed my flight to stay compliant with rvsm using the block altitudes. There were no conflicts. With that said; rvsm airspace should have reverted to non-rvsm separation in this sector when moderate mountain wave was reported.
Original NASA ASRS Text
Title: AN LJ60 PLT RPTS ACFT'S INABILITY TO MAINTAIN RVSM REQUIREMENT IN MOUNTAIN WAVE ACTION AND RECEIVING BLOCK ALT CLRNCS.
Narrative: MODERATE MOUNTAIN WAVE WAS ENCOUNTERED AND A BLOCK ALT FL400-FL430 WAS REQUESTED AND APPROVED. IN THE BLOCK 500 FT DEVS AT .04 MI AIRSPD FLUCTUATIONS OCCURRED EVEN WITH FULL AND IDLE PWR INPUTS. THE ALT EXCURSIONS WERE NECESSARY TO STAY BELOW MMO AND ABOVE THE MINIMUM SAFE SPD. A LOWER BLOCK FL380-FL400 WAS REQUESTED. CTR ASSIGNED FL390 WHERE THE ALT EXCURSIONS WERE +/-170 FT. THE BLOCK FL390-FL410 WAS FINALLY ASSIGNED WHEN I ADVISED CTR THAT IF MY FLT DIDN'T GET A BLOCK ALT I WOULD HAVE TO DECLARE 'UNABLE RVSM DUE TO MOUNTAIN WAVE.' PROMPT COM AND COORD ALLOWED MY FLT TO STAY COMPLIANT WITH RVSM USING THE BLOCK ALTS. THERE WERE NO CONFLICTS. WITH THAT SAID; RVSM AIRSPACE SHOULD HAVE REVERTED TO NON-RVSM SEPARATION IN THIS SECTOR WHEN MODERATE MOUNTAIN WAVE WAS RPTED.
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.