Beech 35-C33 accident near Longmont, Colorado, July 18, 2021
On July 18, 2021 at about 2:50 pm local time, a 1965 Beech 35-C33, registered N18AR, was substantially damaged in an accident during initial climb near Longmont, Colorado (Vance Brand airport). It was a personal flight under general aviation rules (Part 91). 1 person was seriously injured and 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The airplane’s lack of climb performance after takeoff in high density altitude conditions for reasons that could not be determined based on the available evidence.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 18, 2021 · about 2:50 pm local time
- Place
- Longmont, Colorado · Vance Brand · map
- Type
- Accident
- Injuries
- 1 person was seriously injured and 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Beech 35-C33, built 1965 · all 35-C33s on the register
- Registration
- N18AR · registry record · serial CD-959
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot was departing on a personal flight with a density altitude of 6,804 ft. After takeoff, the airplane’s climb rate “did not look normal,” and the pilot was not certain that the airplane would clear a house located along the departure path. He decided to execute a precautionary landing to a hayfield about 1/3 mile from the departure end of the runway. The pilot retracted the landing gear, and the airplane touched down and slid to a stop on its belly. Airplane performance data indicated that the expected initial rate of climb was about 780 ft per minute. Airframe and engine examinations did not reveal any anomalies consistent with an inability to maintain the published rate of climb or to produce rated engine power. Therefore, the investigation was unable to determine the reason for the lack of climb performance. Regardless, the pilot’s decision to execute a precautionary landing under the circumstances was prudent.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Unknown or undetermined during initial climb defining event
The NTSB's findings
- Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Climb rate › Not attained/maintained
- Not determined › Not determined › (general) › (general) › Unknown/Not determined
Pilot
- Certificate: private
- Ratings: single-engine land; instrument: airplane
- Flight time: 1,290 hours in all; 977 in this make and model; 33 in the last 90 days
- Last flight review: May 6, 2020
- Medical certificate: BasicMed (without waivers/limitations)
- Seat: left
- Injury: serious injuries
The aircraft
- Airframe total time: 7,339 hours
- Last inspection: annual inspection, October 30, 2020; 58 hours since
- Maximum gross weight: 3,050 lb
- Seats: 4
- Landing gear: retractable
- Engine: Continental IO-470N (piston); 2,942 hours total
The flight
- Departed from: LMO Longmont CO at 2:55 pm
- Destination: RDK Red Oak IA
- Flight plan: IFR
- Runway 29, 4,799 ft by 75 ft
Weather at the time
- Light: daylight
- Wind: from 110° at 3 knots
- Visibility: 7 statute miles
- Sky: clear
- Temperature: 73°F (23°C), dew point 52°F (11°C)
- Altimeter: 30.31 inHg
- Observation at 8:55 am from LMO, 1 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
8 documents, released by the NTSB on October 14, 2022. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 9 pages | View Download |
| 2 | Accident Photos | PDF, 5 pages | View Download |
| 3 | Airplane Examination Summary | PDF, 4 pages | View Download |
| 4 | Airplane Flight Manual -- Section 5 / Performance | PDF, 34 pages | View Download |
| 5 | Surface Weather Observations -- Vance Brand Airport (Klmo) | PDF, 3 pages | View Download |
| 6 | Release of Aircraft Wreckage, NTSB Form 6120.15 | PDF, 1 page | View Download |
| 7 | Statement of Party Representatives to NTSB Investigation | PDF, 1 page | View Download |
| 8 | Density Altitude Calculator | PDF, 1 page | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.