# NTSB MKC89LA161: Gates Learjet Learjet 35, N701AS, Des Moines, IA, July 18, 1989

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: July 18, 1989, 02:30 local (07:30 UTC)
- Place: Des Moines, IA
- Location: 41.5340° N, 93.6631° W: Placed by OpenAirDocs at DES MOINES INTL (DSM), within about a mile (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=41.5340&lon=-93.6631&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor, 2 uninjured
- Status: Completed, report March 29, 1991
- Report: Approved by Office Director
- NTSB case key (mKey): 34832
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MKC89LA161
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/34832/pdf
- Page: https://openairdocs.org/ntsb/MKC89LA161

## Probable cause

FAILURE OF THE PILOT TO MAINTAIN DIRECTIONAL CONTROL AND RUNWAY ALIGNMENT DURING THE LANDING.  FACTORS RELATED TO THE ACCIDENT WERE:  ADVERSE WEATHER/RUNWAY/TERRAIN CONDITIONS, FAILURE OF THE LOCAL CONTROLLER TO WARN THE PILOT OF POSSIBLE HYDROPLANING CONDITIONS, THE PILOT'S DECISION NOT TO USE REVERSE THRUST, AND RUNWAY LIGHT ABUTMENTS.

## 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 - rain (contributing factor)
  - airport facilities,runway/landing area condition - wet (contributing factor)
  - communications/information/atc - information insufficient, atc personnel(lcl/gnd/clnc) (contributing factor)
  - reversers - not used, pilot in command (contributing factor)
  - aircraft performance,hydroplaning condition (contributing factor)
  - weather condition - crosswind (contributing factor)
  - directional control - not maintained, pilot in command (cause)
  - proper alignment - not maintained, pilot in command (cause)
- On ground/water collision with object, landing - roll
  - terrain condition - soft (contributing factor)
  - object - runway light (contributing factor)

## Analysis

THE PIC RPRTD THAT DURING AN IFR ARRIVAL TO THE DES MOINES INTL ARPT, HE DETECTED WHAT SEEMED TO BE MICROBURSTS & ELECTED TO MAKE A MISSED APCH. DURING A 2ND APCH (ILS RWY 30R APCH), WX CONDITIONS WERE BETTER & TOWER PSNL RPRTD ONLY LIGHT RAIN & WINDS, SO HE CONTINUED FOR A LANDING. THE APCH & TOUCHDOWN WERE NORMAL & REVERSE THRUST WAS NOT USED. HOWEVER, THE PLT RPRTD THAT WHEN HE APPLIED BRAKES, HE REALIZED THE ACFT WAS HYROPLANING. SOON THEREAFTER, IT ANGLED OFF THE RIGHT SIDE OF THE RWY, THOUGH IT WAS BEING STEERED TO THE LEFT. THE ACFT THEN ENCTRD SOFT MUD, HIT 2 LANDING LIGHT ABUTMENTS & WAS DAMAGED. THE RWY WAS RPRTD TO SLOPE DOWNWARD TOWARD THE MIDPOINT. THE PLT STATED THAT A FEW HRS LATER, WATER WAS STILL STANDING IN LOW POINTS ON THE RWY, THOUGH RAIN HAD STOPPED FALLING. ALSO, HE STATED THE LOCAL CONTROLLER HAD NOT WARNED HIM OF POSSIBLE HYDROPLANING THOUGH AT LEAST 2 INCHES OF RAIN HAD FALLEN IN A SHORT PERIOD BEFORE THE PLANE HAD LANDED. THE 0244 CDT WIND WAS RPRTD TO BE FROM 200 DEG AT 9 KTS.

## Aircraft

- Registration: [N701AS](https://openairdocs.org/deregistered/N701AS-2024-05-01), registration cancelled 2024-05-01, S/N 047, built 1976 (OpenAirDocs)
- Reported make and model: Gates Learjet LEARJET 35
- Registry model: [Gates Lear Jet 35](https://openairdocs.org/model/gates-lear-jet-35) (registry code 5170600) (OpenAirDocs)
- Registry engine: [Garrett TFE731 series](https://openairdocs.org/engine/garrett-tfe731-series) (registry code 29001, turbo-fan) (OpenAirDocs)
- Category: Airplane
- Serial number: 047
- Airframe hours: 7364
- Engines: GARRETT TFE-731-2-2B 3500 lbs thrust turbo fan
- Damage: Substantial damage
- Flight: Part 135
- Registered owner: New Creations, Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: AAIP, June 4, 1989, 175 hours before
- Departed: DEN, DENVER, CO
- Flight plan: IFR
- Airport: DSM, Des Moines Intl, runway 30R, 9,001 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 30; airline transport, flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 6,554 total, 2,334 in this make and model, 5,471 as pilot in command, 270 in the last 90 days, 89 in the last 30 days, 3 in the last 24 hours

## Weather

- Conditions: Instrument (IMC), Night/dark
- Wind: 200° at 9 knots
- Visibility: 1 statute miles
- Lowest ceiling: 1,400 ft broken
- Temperature: 72 °F, dew point 68 °F
- Altimeter: 29.00 inHg
- Observed at: DSM, 1 nm away

## 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 19890718026449A](https://openairdocs.org/incident/19890718026449A), Jul 18, 1989: Lear 35LEAR, Des Moines, IA, Substantial damage. Landed on wet runway without using thrust reversers, hydroplaned and left the runway into mud. Hit concrete anchors

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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