- Date
- September 29, 1999, 18:40 local (Sep 30, 1999, 00:40 UTC)
- Place
- Longmont, CO
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Approach
- Aircraft
- N84DHEnstrom 280C
- Weather
- Visual (VMC) · Day
- Status
- Completed · report June 22, 2000
- Report
- Approved by Office Director
- FAA report
- 19990929047519A
- Case key
- 47476
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
An inaccurate touchdown during a full autorotation, which resulted in main rotor flex which cut off the tail boom. Factors were the pilot's lack of total experience in helicopters and high density altitude.
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
While practicing autorotations, the pilot, who was a commercial pilot in single and multiengine aircraft but a student pilot in helicopters, experienced a loss of engine power for unknown reasons. During the full autorotation, which was necessitated by the power loss, the landing was hard and resulted in main rotor flex, which cut off the tail boom. Density altitude at the time was 9,000 feet.
Factual narrative
On September 29, 1999, at 1840 mountain daylight time, an Enstrom 280C helicopter, N84DH, sustained substantial damage during a hard landing, after a practice autorotation, at Vance Brand Airport, Longmont, Colorado. The non-helicopter rated commercial pilot and sole occupant was not injured. The flight was a local solo instructional flight operating under Title 14 CFR Part 91 and no flight plan was filed. Visual meteorological conditions prevailed.
According to the pilot, he was practicing autorotations and the engine lost power while in an autorotation. During the ensuing hard landing, the main rotor flexed and cut of the tail boom. Density altitude at the time was 9,000 feet.
The pilot reported that he had 40 hours flight experience in helicopters and that all his helicopter experience was in the Enstrom 280C. He said he had 11 hours of helicopter experience in the 30 days prior to the accident, and 40 hours in the preceding 90 days.
No evidence was developed during the investigation as to the reason for the power loss.
Aircraft
- Registration
- N84DH
- Reported as
- Enstrom 280C
- Category
- Helicopter
- Serial number
- 1055
- Airframe hours
- 688
- Engine
- Lycoming HIO-360-E1AD, 205 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Instructional · Part 91
- Operator
- Jeffery J. Sands
- Registered owner
- Mile High Skydivers, Inc.
- Airworthiness certificate
- Standard, Normal
- Last inspection
- Annual · April 5, 1999 · 12 hours before
- Departed
- 2V2
- Airport
- 2V2 · Vance Brand, runway 29, 4,800 × 75 ft, concrete
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
- 46
- Certificate
- Commercial
- Airplane ratings
- Multi-engine land, Single-engine land
- Instrument ratings
- Airplane
- Medical
- Class 2, Valid Medical--no waivers/lim.
- Seat
- Left
- Flight hours
- 2,127 total · 40 in this make and model · 2,004 as pilot in command · 91 in the last 90 days · 30 in the last 30 days · 1 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 250° at 6 knots
- Visibility
- 40 statute miles
- Lowest ceiling
- None
- Temperature
- 97 °F, dew point 86 °F
- Altimeter
- 30.00 inHg
- Observed at
- BJC, 15 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.