# NTSB MKC84LA274: Gates Learjet LR-24D, N45AJ, Chesterfield, MO, September 11, 1984

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: September 10, 1984, 20:50 local (Sep 11, 1984, 01:50 UTC)
- Place: Chesterfield, MO
- Coordinates: 38.64928, -90.530822 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=38.6493&lon=-90.5308&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 33789
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MKC84LA274
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/33789/pdf
- Page: https://openairdocs.org/ntsb/MKC84LA274

## Sequence of events

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

- Loss of control - on ground/water, landing - roll
  - weather condition - unfavorable wind (contributing factor)
  - in-flight planning/decision - improper, pilot in command (cause)
  - weather condition - rain (contributing factor)
  - visual lookout - reduced, pilot in command (contributing factor)
  - airport facilities,runway/landing area condition - wet (contributing factor)
  - airspeed - excessive, pilot in command (contributing factor)
  - aircraft performance,hydroplaning condition - water
  - directional control - not possible, pilot in command
- On ground/water encounter with terrain/water, landing - roll
  - terrain condition - rough/uneven (contributing factor)
  - landing gear,main gear - overload
  - wing - overload

## Analysis

THE ACFT WAS LANDED IN A THUNDERSTORM WITH A 16 KT LEFT QUARTERING TAILWIND. THE PLT WAS AWARE OF AN AREA ON THE RWY WHICH TENDED TO COLLECT WATER BUT DUE TO HEAVY PRECIPITATION THIS AREA COULD NOT BE VIEWED FROM THE COCKPIT. THE LEFT MAIN GEAR HYDROPLANED AS IT CONTACTED THIS AREA DURING THE LANDING ROLL RESULTING IN A 90 DEG RIGHT TURN. THE ACFT DEPARTED THE RIGHT SIDE OF THE RWY TRAVELING INTO ROUGH TERRAIN AT WHICH TIME THE LEFT MAIN GEAR PUNCTURED THE WING. HYDROPLANE MARKS WERE VISIBLE ON BOTH LEFT MAIN GEAR TIRES AFTER THE ACCIDENT.

## Aircraft

- Registration: N45AJ (not matched to a registry record)
- Reported make and model: Gates Learjet LR-24D
- Category: Airplane
- Serial number: 24D-309
- Airframe hours: 5032
- Engines: GE CJ610-6 2950 lbs thrust turbo jet
- Damage: Substantial damage
- Flight: Part 135
- Operator: St.Louis Flight Systems,Inc.
- Registered owner: Amer. Jet. Leasing, Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: Continuous airworthiness, February 16, 1984, 132 hours before
- Departed: DET, DETROIT, MI
- Destination: SUS, CHESTERFIELD, MO
- Flight plan: IFR
- Airport: SUS, Spirit Of St. Louis, runway 7, 6,008 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 30; airline transport; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 3,350 total, 3,000 in this make and model, 126 as pilot in command, 90 in the last 90 days, 4 in the last 24 hours

## Weather

- Conditions: Instrument (IMC), Night/dark
- Wind: 360° at 15 knots
- Visibility: 5 statute miles
- Lowest ceiling: 1,500 ft overcast
- Temperature: 75 °F

## 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 19840910049569A](https://openairdocs.org/incident/19840910049569A), Sep 10, 1984: Lear 24D, Chesterfield, MO, Substantial damage. Aircraft ran off right side of runway during landing in rain storm pilot claims aircraft hydroplaned.

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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