# NTSB MKC87LA119: Beech B35, N7973D, Keokuk, IA, June 5, 1987

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: June 5, 1987, 09:45 local (14:45 UTC)
- Place: Keokuk, IA
- Coordinates: 40.400165, -91.400459 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=40.4002&lon=-91.4005&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious, 1 minor
- Status: Completed, report November 29, 1988
- Report: Approved by Office Director
- NTSB case key (mKey): 34396
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MKC87LA119
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/34396/pdf
- Page: https://openairdocs.org/ntsb/MKC87LA119

## Sequence of events

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

- Loss of engine power(partial) - mech failure/malf, cruise - normal
  - engine instruments,manifold pressure gage - pressure too low (contributing factor)
  - fuel system,carburetor - disconnected (cause)
  - maintenance,inspection - inadequate, other maintenance personnel (contributing factor)
- Forced landing, descent - emergency
  - descent - not maintained, pilot in command (contributing factor)
  - go-around - attempted, pilot in command
- In flight collision with object, maneuvering - turn to landing area (emergency)
  - object - tree(s) (contributing factor)
  - planned approach - poor, pilot in command (contributing factor)

## Analysis

THE PIC RPTD A LOSS OF MANIFOLD PRESS DURING CRUISE FLT AND AN INABILITY TO MAINTAIN ALT. A FORCED LNDG WAS MADE TO THE KEOKUK ARPT, BUT THE PIC STATED HE WAS TOO HIGH AND FAST FOR A LNDG. THE PIC MADE A GO-AROUND, BUT AGAIN APPROACHED TOO FAST. ANOTHER ATTEMPT WAS MADE TO GO-AROUND, BUT AN INCREASE IN THROTTLE PRODUCED NO ADD'TL PWR. THE PIC THEN VEERED TOWARDS AN OPEN AREA TO ATTEMPT A LNDG. THE ACFT IMPACTED AN AREA OF TREES AND FELL TO THE GRND. EXAM OF THE AIRCRAFT REVEALED THAT THE THROTTLE ARM WAS SLIPPING OVER THE SERRATED EDGES OF THE THROTTLE BODY SHAFT RESTRICTING FULL MOVEMENT OF THE THROTTLE SHAFT. CLOSEUP EXAM OF THIS ARM AND SHAFT REVEALED THAT THE CASTELATED NUT HAD BACKED OFF THE BOLT ALLOWING THE ARM TO LOOSEN. A COTTER PIN IS NORMALLY INSTALLED IN THE AREA OF THE CASTELATTED NUT TO PREVENT IT FROM BACKING OFF THE BOLT. THE BOLT AND NUT WERE FOUND STILL POSITIONED ON THE THROTTLE ARM, BUT THE COTTER PIN WAS NOT FOUND.

## Aircraft

- Registration: [N7973D](https://openairdocs.org/deregistered/N7973D-1988-04-06), registration cancelled 1988-04-06, S/N D5233 (OpenAirDocs)
- Reported make and model: BEECH B35
- Registry model: [Beech H35](https://openairdocs.org/model/beech-h35) (registry code 1151520) (OpenAirDocs)
- Category: Airplane
- Serial number: 5233
- Airframe hours: 3900
- Engines: CONTINENTAL O-470 250 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: George J. Zimmer
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, December 1, 1986, 49 hours before
- Departed: MUT, MUSCATINE, IA
- Destination: HOUSTON, TX
- Airport: EOK, Keokuk Municipal, runway 31, 3,800 × 100 ft, grass/turf

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 62; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 1,598 total, 609 in this make and model, 15 in the last 90 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 15 statute miles

## 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 19870605019029A](https://openairdocs.org/incident/19870605019029A), Jun 5, 1987: Beech H35, Keokuk, IA, Substantial damage. Collided with trees after attempting to land. Throttle control linkage had separated. Unable to control aircraft.

## Other investigations on N7973D (1)

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.

- [NTSB UNK64X0685](https://openairdocs.org/ntsb/UNK64X0685), Feb 24, 1964: Beechcraft B35 (N7973D), Friendly, MD, substantial damage

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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