# NTSB MKC83LA183: Beech M35, N555M, Sioux City, IA, August 8, 1983

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: August 8, 1983, 15:20 local (20:20 UTC)
- Place: Sioux City, IA
- Location: 42.4013° N, 96.3844° W: Placed by OpenAirDocs at SIOUX GATEWAY/BRIG GENERAL BUD DAY FLD (SUX), within about a mile (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=42.4013&lon=-96.3844&mi=10
- Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 33464
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MKC83LA183
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/33464/pdf
- Page: https://openairdocs.org/ntsb/MKC83LA183

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Gear collapsed, takeoff - roll/run
  - reason for occurrence undetermined (cause)

## Analysis

THE PLT STATED THAT THE LANDING GEAR SWITCH WAS DOWN WHEN HE STARTED THA TAKEOFF ROLL. WHEN THE ACFT HAD ACCELERATED TO APRX 50 MPH DURING THE TAKEOFF ROLL, THE LANDING GEAR RETRACTED/COLLAPSED, NOSE WHEEL FIRST, FOLLOWED BY THE MAIN GEAR. THE PLT STATED THAT AFTER THE ACFT SLID TO A STOP, HE MOVED THE LANDING GEAR SWITCH FROM THE 'DOWN' TO THE 'UP' POSITION BEFORE HE DEPARTED THE ACFT. MAINTENANCE PERSONNEL WHO WERE AT THE ACFT IMMEDIATELY AFTER THE MISHAP, CONFIRMED THAT THE LANDING GEAR SWITCH WAS IN THE 'UP' POSITION WHEN THEY ARRIVED. AN INSPECTION OF THE LANDING GEAR & GEAR WARNING SYSTEMS REVEALED NO EVIDENCE OF A PRE-ACCIDENT MALFUNCTION. THE GEAR WARNING HORN SOUNDED WHEN CHECKED WITH THE SQUAT SWITCH OPEN. THE PLT STATED THAT HE DID NOT HEAR A HORN DURING THE TAKEOFF SEQUENCE. ALSO, THE PLT NOTED THAT THE FLAP SWITCH WAS IN THE 'DOWN' POSITION, WHEN HE ARRIVED AT THE ACFT, BUT THE FLAPS WERE IN THE RETRACTED POSITION. HE BELIEVED SOMEONE HAD PUT THE FLAP SWITCH DOWN AFTER THE MASTER SWITCH WAS OFF.

## Aircraft

- Registration: [N555M](https://openairdocs.org/deregistered/N555M-2022-05-09), registration cancelled 2022-05-09, S/N D-6216, built 1959 (OpenAirDocs)
- Reported make and model: BEECH M35
- Registry model: [Beech M35](https://openairdocs.org/model/beech-m35) (registry code 1151526) (OpenAirDocs)
- Registry engine: [Continental I0-470 series](https://openairdocs.org/engine/continental-i0-470-series) (registry code 17027, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: D6216
- Airframe hours: 4119
- Engines: CONTINENTAL IO-470-C 250 horsepower reciprocating
- Damage: Substantial damage
- Flight: Business, Part 91
- Operator: Airways Service Inc.
- Registered owner: Fredrick Mersch
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, April 26, 1983, 78 hours before
- Destination: RBE, BASSETT, NE
- Airport: SUX, Sioux City Municipal, runway 22, 6,888 × 150 ft, concrete

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 47; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 507 total, 400 in this make and model, 406 as pilot in command, 20 in the last 90 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 80° at 5 knots
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 93 °F, dew point 66 °F
- Altimeter: 29.00 inHg
- Observed at: SUX

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19830808041989A](https://openairdocs.org/incident/19830808041989A), Aug 8, 1983: Beech M35, Sioux City, IA, Substantial damage. Gear retracted during takeoff ground roll. Pilot claims malfunction but no evidence of failure was found.

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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