- Date
- February 9, 2015, 17:00 local (Feb 10, 2015, 01:00 UTC)
- Place
- Mammoth Lakes, CA
- Injuries
- 2 uninjured
- Damage
- Substantial damage
- Phase of flight
- Enroute
- Aircraft
- N49WCRaytheon B300
- Defining event
- Enroute-descent: Turbulence encounter
- Weather
- Visual (VMC) · Day
- Status
- Completed · report June 1, 2015
- Report
- Approved by Office Director
- NTSB office
- Western Pacific Region
- Parties
- Textron Aviation, FAA
- FAA report
- 20150209001259A
- Case key
- 90758
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
The airplane encountered extreme turbulence during descent.
Findings · 1
NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.
Sequence of events
The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.
Analysis
The pilot reported that while in a descent from 16,000 feet, at 1,500 feet per minute, slowing from 190 knots indicated airspeed to 160 knots, the airplane encountered extreme turbulence. The pilot reported one hard jolt up/down followed by about 15 seconds of light turbulence then one final hard jolt similar to the first. The weather was visual conditions and no turbulence was encountered prior to or after the event. A postflight examination of the airplane revealed that the extreme turbulence encountered resulted in substantial structural damage to both wings spars. The pilot reported there were no pre-impact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation.
Factual narrative
The pilot reported that while in a descent from 16,000 feet, at 1,500 feet per minute, slowing from 190 knots indicated airspeed to 160 knots, the airplane encountered extreme turbulence. The pilot reported one hard jolt up/down followed by about 15 seconds of light turbulence then one final hard jolt similar to the first. The weather was visual conditions and no turbulence was encountered prior to or after the event. A postflight examination of the airplane revealed that the extreme turbulence encountered resulted in substantial structural damage to both wings spars. The pilot reported there were no pre-impact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation.
Aircraft
- Registration
- N49WC
- Reported as
- Raytheon B300 (UNDESIGNAT)
- Category
- Airplane
- Serial number
- FL-144
- Built
- 1996
- Airframe hours
- 9,205.5
- Engines
- Pratt & Whitney PT6A-60A, 1,050 horsepower, turbo propPratt & Whitney PT6A-60A, 1,050 horsepower, turbo prop
- Damage
- Substantial damage
- Flight
- Positioning · Part 91
- Operator
- West Coast Charters Inc
- Registered owner
- American Career College Inc
- Airworthiness certificate
- Standard, Commuter
- Last inspection
- Continuous airworthiness · January 6, 2015 · 55 hours before
- Departed
- SNA · Santa Ana, CA
- Destination
- MMH · Mammoth Lakes, CA
- Flight plan
- IFR
- Airport
- MMH · Mammoth Yosemite, runway 27, 7,000 × 100 ft, asphalt
- Equipment
- Electronic multifunction display, Electronic flight bag or handheld device, Auto-pilot, Stall warning system, Onboard weather, Electronic primary flight display
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew · 2
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 36
- Injuries
- None
- Certificates
- Flight instructor, Airline transport
- Airplane ratings
- Single-engine land, Multi-engine land
- Instrument ratings
- Airplane
- Medical
- Class 1, Without waivers/limitations
- Last flight review
- January 14, 2015
- Seat
- Left
- Restraint
- 4-point
- Flight hours
- 3,800 total · 1,300 in this make and model · 3,009 as pilot in command · 110 in the last 90 days · 22 in the last 30 days · 7 in the last 24 hours
- Role
- Co-pilot
- Age
- 28
- Injuries
- None
- Certificates
- Commercial, Flight instructor
- Airplane ratings
- Multi-engine land, Single-engine land
- Instrument ratings
- Airplane
- Medical
- Class 1, Without waivers/limitations
- Last flight review
- June 20, 2014
- Seat
- Right
- Restraint
- 4-point
- Flight hours
- 2,180 total · 100 in this make and model · 2,035 as pilot in command · 18 in the last 90 days · 9 in the last 30 days · 1.2 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 210° at 5 knots
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 64 °F, dew point 12 °F
- Altimeter
- 30.02 inHg
- Observed at
- KBIH, 28 nm away
Docket · 7
The files NTSB released with the investigation on May 18, 2015, on NTSB’s docket system: statements, records, photos and specialists’ reports. 2.6 MB in all.
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.