CEN21LA325

NTSB accident investigation · Beech 35-C33 · Longmont, CO · July 18, 2021

Accident · Serious injuriesClass 3 · LimitedFinal report
Date
July 18, 2021, 08:50 local (14:50 UTC)
Place
Longmont, CO
Injuries
1 serious, 1 minor
Damage
Substantial damage
Phase of flight
Initial climb
Aircraft
N18ARBeech 35-C33
Defining event
Initial climb: Unknown or undetermined
Weather
Visual (VMC) · Day
Status
Completed
Report
Approved by Office Director
Investigation class
Class 3
NTSB office
Central Region
Parties
Textron Aviation, FAA Flight Standards
FAA report
20210718022039A
Case key
103498

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 lack of climb performance after takeoff in high density altitude conditions for reasons that could not be determined based on the available evidence.

Findings · 2

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.

Performance/control parameters: climb rateAircraft › Aircraft oper/perf/capability · Not attained/maintainedBeech 35-C33: 1 caseAll aircraft: 265 casesProbable cause
Not determinedNot determined › Not determined · Unknown/Not determinedBeech 35-C33: 2 casesAll aircraft: 2,247 casesProbable cause

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 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.

Factual narrative

On July 18, 2021, about 0850 mountain daylight time, a Beech 35-C33 airplane, N18AR, was substantially damaged when it was involved in an accident near Vance Brand Airport (LMO), Longmont, Colorado. The pilot and passenger sustained serious and minor injuries, respectively. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that the preflight inspection and run-up were normal and that, per the high-density altitude procedures, he leaned the fuel mixture before takeoff from the 4,799-ft-long runway. He rotated at 85 mph and initiated a climb; however, the airspeed and climb rate “did not look normal.” He was not certain that the airplane would clear a house located along the departure path and decided to execute a precautionary landing. He retracted the landing gear and entered a right turn to avoid the house. The airplane touched down and slid to a stop on its belly. The airplane impacted a hayfield and came to rest about 1/3 mile from the departure end of the runway. The fuselage and both wings sustained substantial damage consistent with the impact sequence. Post-recovery airframe and engine examinations did not reveal any anomalies consistent with a loss of engine power. Based on the 0855 weather observation at LMO, the calculated density altitude for the takeoff was 6,804 ft. Airplane performance data indicated that the expected takeoff distance to clear a 50-ft obstacle and the expected initial rate of climb were about 2,900 ft and 780 ft per minute, respectively. The pilot reported previous flight experience at high-density altitude airports that included flight instruction for such operations.

Aircraft

Registration
N18AR
Reported as
Beech 35-C33
Category
Airplane
Serial number
CD-959
Built
1965
Airframe hours
7,339
Engine
Continental IO-470N, 260 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Airworthiness certificate
Standard, Normal; Standard, Utility
Last inspection
Annual · October 30, 2020 · 58 hours before
Departed
LMO · Longmont, CO
Destination
RDK · Red Oak, IA
Flight plan
IFR
Airport
LMO · Vance Brand, runway 29, 4,799 × 75 ft, concrete
Equipment
Electronic flight bag or handheld device, Auto-pilot, ADS-B, Stall warning system, Onboard weather

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
69
Injuries
Serious
Certificate
Private
Airplane ratings
Single-engine land
Instrument ratings
Airplane
Medical
BasicMed, Without waivers/limitations
Last flight review
May 6, 2020
Seat
Left
Restraint
4-point
Flight hours
1,290 total · 977 in this make and model · 33 in the last 90 days

Weather

Conditions
Visual (VMC) · Day
Wind
110° at 3 knots
Visibility
7 statute miles
Lowest ceiling
None
Temperature
73 °F, dew point 52 °F
Altimeter
30.31 inHg
Observed at
LMO, 1 nm away

Docket · 8

The files NTSB released with the investigation on October 14, 2022, on NTSB’s docket system: statements, records, photos and specialists’ reports. 30.6 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.