- Date
- August 16, 1998, 16:30 local (22:30 UTC)
- Place
- Boulder, CO
- Injuries
- 3 minor
- Damage
- Substantial damage
- Phase of flight
- Landing
- Aircraft
- N2574VCessna 170
- Weather
- Visual (VMC) · Day
- Status
- Completed · report January 28, 2000
- Report
- Approved by Office Director
- FAA report
- 19980816021079A
- Case key
- 43768
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 pilot's intentional ground loop and his inadequate compensation for the wind condition. A contributng factor was crosswinds.
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
As the pilot approached the airport for a full stop landing, he heard the pilot of another airplane, which was landing on runway 8 report that he had a tail wind during his landing sequence. The pilot 'noticed the wind sock on the east end of the runway was standing straight out in a direction that appeared to be 180 degrees.' The pilot landed on runway 26, but reported having difficulty keeping the airplane aligned with the centerline. He said 'I didn't feel at the time I stood any chance of gaining airspeed to execute a climb.' He performed a ground loop rather then go in the lake on the west end of the runway. One witness reported that immediately after the accident they noticed that the wind was coming from the northeast. The winds at the nearest reporting station, 9 nautical miles southeast, were 180 degrees and 13 knots at 1549 and at 1655, the winds were 150 degrees and 11 knots gusting to 20 knots.
Factual narrative
On August 16, 1998, approximately 1630 mountain daylight time, a Cessna 170, N2574V, was substantially damaged following an intentional ground loop initiated by the pilot at Boulder Municipal Airport, Boulder, Colorado. The private pilot and his two passengers received minor injuries. The airplane was being operated by the pilot under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the personal cross-country flight which originated from Ogallala, Nebraska, approximately 2 hours before the accident. A VFR flight plan had been filed.
The pilot reported that as he approached Boulder Municipal Airport (elevation 5,288 feet, density altitude 7,807 feet) for a full stop landing, he heard the pilot of another airplane which was landing on runway 8 report that he had a tail wind during his landing. The pilot said that he "noticed the wind sock on the east end of the runway was standing straight out in a direction that appeared to be 180 degrees." The pilot landed on runway 26, but reported having difficulty keeping N2574V aligned with the centerline. He said, "I immediately determined to execute a go around. I had trimmed nose up for landing so I was attempting to get the nose down but was also buffeted by very turbulent winds [coming] over the hangers to the south." The pilot said that he believed it was safer to perform a ground loop then to go in the lake at the west end of the runway. He said, "I didn't feel at the time I stood any chance of gaining airspeed to execute a climb."
One witness reported that immediately after the accident, they noticed that the wind was coming from the northeast. The winds at Jefferson County Airport (BJC), which is 9 nm southeast of Boulder Municipal Airport, were 180 degrees and 13 knots at 1549. At 1655, the winds at BJC were 150 degrees and 11 knots gusting to 20 knots.
Aircraft
- Registration
- N2574V
- Reported as
- Cessna 170
- Category
- Airplane
- Serial number
- 18111
- Airframe hours
- 5,688
- Engine
- Continental C145-2, 145 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Personal · Part 91
- Registered owner
- Eric D. Twombly
- Airworthiness certificate
- Standard, Normal
- Last inspection
- Annual · August 6, 1997 · 126 hours before
- Departed
- OGA · Ogallala, NE
- Destination
- 1V5
- Flight plan
- VFR
- Airport
- 1V5 · Boulder Municipal, runway 26, 4,100 × 75 ft, asphalt
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
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 47
- Certificate
- Private
- Airplane ratings
- Single-engine land
- Medical
- Class 3, Valid Medical--w/ waivers/lim
- Seat
- Left
- Flight hours
- 1,068 total · 1,025 in this make and model · 1,003 as pilot in command · 47 in the last 90 days · 30 in the last 30 days · 6 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 150° at 11 knots, gusting 20
- Visibility
- 50 statute miles
- Lowest ceiling
- 20,000 ft broken
- Temperature
- 81 °F, dew point 52 °F
- Altimeter
- 30.00 inHg
- Observed at
- BJC, 9 nm away
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.