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Learjet 35 flight crew lost temporary altitude control when entering moderate turbulence over mountainous terrain resulting in a loss of altitude from assigned.
| Attributes | |
| ACN | 540347 |
| Time | |
| Date | 200203 |
| Day | Sun |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : apa.airport |
| State Reference | CO |
| Altitude | msl bound lower : 13500 msl bound upper : 14000 |
| Environment | |
| Flight Conditions | VMC |
| Weather Elements | Windshear Turbulence |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : d01.tracon tower : sju.tower |
| Operator | general aviation : corporate |
| Make Model Name | Learjet 35 |
| Operating Under FAR Part | Part 91 |
| Flight Phase | descent : approach |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : corporate |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : commercial pilot : cfi pilot : atp pilot : multi engine |
| Experience | flight time last 90 days : 90 flight time total : 4000 flight time type : 2000 |
| ASRS Report | 540347 |
| Person 2 | |
| Affiliation | company : corporate |
| Function | flight crew : first officer |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude inflight encounter : turbulence non adherence : clearance |
| Independent Detector | aircraft equipment other aircraft equipment : altimeter other flight crewa other flight crewb |
| Resolutory Action | flight crew : returned to assigned altitude |
| Consequence | faa : reviewed incident with flight crew |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance Weather Environmental Factor |
| Primary Problem | Environmental Factor |
Narrative:
On the larks 3 arrival from aspen, co, passing murfe intersection, level at 15000 ft MSL, given descent to 14000 ft MSL. Initiated descent at 300 KIAS, encountered continuous moderate turbulence with intermittent severe turbulence. Thrust levers retarded to idle, spoilers extended, engine ignition turned on. Speed reduced to 250 KIAS (recommended turbulence penetration speed). Bank angle varying +/-30 degrees, accompanied by sharp and abrupt up and down oscillations. During this encounter, altitude deviated to 13500 ft MSL for about 15 seconds. Upon recognition, spoilers retracted and climb to 14000 ft initiated. PIREP issued to approach and descent given to 11000 ft MSL. No conflicts arose from deviation. 1 passenger bumped head, but required no medical attention. Landed apa without incident.
Original NASA ASRS Text
Title: LEARJET 35 FLC LOST TEMPORARY ALT CTL WHEN ENTERING MODERATE TURB OVER MOUNTAINOUS TERRAIN RESULTING IN A LOSS OF ALT FROM ASSIGNED.
Narrative: ON THE LARKS 3 ARR FROM ASPEN, CO, PASSING MURFE INTXN, LEVEL AT 15000 FT MSL, GIVEN DSCNT TO 14000 FT MSL. INITIATED DSCNT AT 300 KIAS, ENCOUNTERED CONTINUOUS MODERATE TURB WITH INTERMITTENT SEVERE TURB. THRUST LEVERS RETARDED TO IDLE, SPOILERS EXTENDED, ENG IGNITION TURNED ON. SPD REDUCED TO 250 KIAS (RECOMMENDED TURB PENETRATION SPD). BANK ANGLE VARYING +/-30 DEGS, ACCOMPANIED BY SHARP AND ABRUPT UP AND DOWN OSCILLATIONS. DURING THIS ENCOUNTER, ALT DEVIATED TO 13500 FT MSL FOR ABOUT 15 SECONDS. UPON RECOGNITION, SPOILERS RETRACTED AND CLB TO 14000 FT INITIATED. PIREP ISSUED TO APCH AND DSCNT GIVEN TO 11000 FT MSL. NO CONFLICTS AROSE FROM DEV. 1 PAX BUMPED HEAD, BUT REQUIRED NO MEDICAL ATTN. LANDED APA WITHOUT INCIDENT.
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.