- Date
- September 1, 2016, 13:12 local (21:12 UTC)
- Place
- Anchorage, AK
- Injuries
- 2 uninjured
- Damage
- Substantial damage
- Phase of flight
- Taxi
- Aircraft
- N52950Cessna 172
- Defining event
- Taxi-to runway: Miscellaneous/other
- Weather
- Visual (VMC) · Day
- Status
- Completed · report January 18, 2017
- Report
- Approved by Office Director
- NTSB office
- General Aviation Accidents
- Parties
- FAA
- FAA report
- 20160901022949A
- Case key
- 94014
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’s encounter with a developing sink hole during taxi on the ramp area.
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 flight instructor reported that during taxi the airplane started to lean to the right, so he looked out of his window to see if the right tire was flat. He further reported that "the ramp was opening up into a 2 foot wide dark black hole" underneath the right main landing gear. The flight instructor and student pilot egressed from the airplane without further incident. A postaccident examination revealed substantial damage to the empennage. The flight instructor reported no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. Photographs provided by Federal Aviation Administration showed that the right main landing gear had broken through the pavement into a sink hole underneath.
Factual narrative
The flight instructor reported that during taxi the airplane started to lean to the right, so he looked out of his window to see if the right tire was flat. He further reported that "the ramp was opening up into a 2 foot wide dark black hole" underneath the right main landing gear. The flight instructor and student pilot egressed from the airplane without further incident. A postaccident examination revealed substantial damage to the empennage. The flight instructor reported no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. Photographs provided by Federal Aviation Administration showed that the right main landing gear had broken through the pavement into a sink hole underneath.
Aircraft
- Registration
- N52950
- Reported as
- Cessna 172 (P)
- Category
- Airplane
- Serial number
- 17274642
- Built
- 1981
- Engine
- Lycoming O-320, 180 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Instructional · Part 91
- Operator
- Land and Sea Aviation Alaska
- Registered owner
- Flight Safety Alaska Inc
- Airworthiness certificate
- Standard, Normal
- Last inspection
- Annual · August 19, 2016
- Departed
- MRI · Anchorage, AK
- Destination
- MRI · Anchorage, AK
- Airport
- MRI · Merrill Field
- Equipment
- Stall warning system
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
- 33
- Injuries
- None
- Certificates
- Commercial, Flight instructor
- Airplane ratings
- Single-engine land, Multi-engine land
- Instrument ratings
- Airplane
- Medical
- Class 1, Without waivers/limitations
- Last flight review
- May 1, 2015
- Seat
- Right
- Restraint
- 3-point
- Flight hours
- 967 total · 600 in this make and model
- Role
- Student pilot
- Age
- 31
- Injuries
- None
- Certificate
- Student
- Medical
- Class 3, Without waivers/limitations
- Seat
- Left
- Restraint
- 3-point
- Flight hours
- 10 total · 10 in this make and model
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 20° at 3 knots
- Visibility
- 10 statute miles
- Lowest ceiling
- 6,500 ft overcast
- Temperature
- 66 °F, dew point 54 °F
- Altimeter
- 30.02 inHg
- Observed at
- PAMR
Docket · 2
The files NTSB released with the investigation on December 12, 2016, on NTSB’s docket system: statements, records, photos and specialists’ reports. 553 KB 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.