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Small aircraft private aircraft encountered mountain wave action and turbulence resulting in airspeed fluctuations as well as altitude excursions.
| Attributes | |
| ACN | 387620 |
| Time | |
| Date | 199712 |
| Day | Sat |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : bzm |
| State Reference | NC |
| Altitude | msl bound lower : 6600 msl bound upper : 7400 |
| Environment | |
| Flight Conditions | Mixed |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : ztl tower : jfk |
| Operator | general aviation : personal |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Operating Under FAR Part | Part 91 |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : single pilot |
| Qualification | pilot : instrument pilot : commercial pilot : atp |
| Experience | flight time last 90 days : 61 flight time total : 3415 flight time type : 850 |
| ASRS Report | 387620 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude inflight encounter other other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : returned to intended course or assigned course |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Weather |
| Air Traffic Incident | other |
Narrative:
During IFR flight over mountainous terrain, aircraft encountered strong thermals (smooth turbulence). Outside air temperature -15 degrees C, wind at altitude 7000 ft MSL estimated 310 degrees at 45 KTS. Aircraft would encounter relatively smooth updrafts. Pilot pitch down until excessive airspeed (caution arc, greater than 170 KIAS) was reached. Moderate turbulence present also. At caution airspeed, altitude fluctuations of 350-400 ft were experienced. Downdrafts encountered where airspeed indications of 90 KTS still caused 250-300 ft excursion below assigned altitude of 7000 ft. Pilot requested altitude block. This phenomenon was experienced 3 times prior to block assignment. Pilot elected to exceed altitude assignments to prevent possible overstressing of airframe due to turbulence. Pilot is afraid of possible repercussions of this action, since he has experienced numerous prior personality conflicts with inspectors in clt, nc, FSDO.
Original NASA ASRS Text
Title: SMA PVT ACFT ENCOUNTERED MOUNTAIN WAVE ACTION AND TURB RESULTING IN AIRSPD FLUCTUATIONS AS WELL AS ALT EXCURSIONS.
Narrative: DURING IFR FLT OVER MOUNTAINOUS TERRAIN, ACFT ENCOUNTERED STRONG THERMALS (SMOOTH TURB). OUTSIDE AIR TEMP -15 DEGS C, WIND AT ALT 7000 FT MSL ESTIMATED 310 DEGS AT 45 KTS. ACFT WOULD ENCOUNTER RELATIVELY SMOOTH UPDRAFTS. PLT PITCH DOWN UNTIL EXCESSIVE AIRSPD (CAUTION ARC, GREATER THAN 170 KIAS) WAS REACHED. MODERATE TURB PRESENT ALSO. AT CAUTION AIRSPD, ALT FLUCTUATIONS OF 350-400 FT WERE EXPERIENCED. DOWNDRAFTS ENCOUNTERED WHERE AIRSPD INDICATIONS OF 90 KTS STILL CAUSED 250-300 FT EXCURSION BELOW ASSIGNED ALT OF 7000 FT. PLT REQUESTED ALT BLOCK. THIS PHENOMENON WAS EXPERIENCED 3 TIMES PRIOR TO BLOCK ASSIGNMENT. PLT ELECTED TO EXCEED ALT ASSIGNMENTS TO PREVENT POSSIBLE OVERSTRESSING OF AIRFRAME DUE TO TURB. PLT IS AFRAID OF POSSIBLE REPERCUSSIONS OF THIS ACTION, SINCE HE HAS EXPERIENCED NUMEROUS PRIOR PERSONALITY CONFLICTS WITH INSPECTORS IN CLT, NC, FSDO.
Data retrieved from NASA's ASRS site as of July 2007 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.