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Accidents · NTSB CHI98LA251 · Final report

Grumman G-164B accident near New Haven, Illinois, July 12, 1998

On July 12, 1998 at about 1:00 pm local time, a Grumman G-164B, registered N6731K, was substantially damaged in an accident near New Haven, Illinois. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).

The NTSB's probable cause their words, unchanged

Water contamination of the fuel system. A related factor was the swampy terrain.

Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.

What the record shows

Date
July 12, 1998 · about 1:00 pm local time
Place
New Haven, Illinois · map
Type
Accident
Injuries
No one was hurt; 1 person was on board or involved.
Weather
visual conditions (good weather)
Aircraft
Grumman G-164B · all G-164Bs on the register
Registration
N6731K · no longer on the register · serial 442-B
Damage
Substantial damage
Flight
Aerial application (crop spraying) flight · agricultural flying rules (Part 137)

The NTSB's narrative final · quoted from the NTSB record

The pilot stated that there was 90 gallons of fuel on board upon departure and that he did nor hear any unusual engine sounds during the loss of engine power. He had completed spraying and was returning to his airstrip at an altitude of 150 ft above ground level for another load when the engine torque reading dropped to 30%. While attempting to increase power, the pilot reported that the engine quit at which time he then preformed an emergency landing to a muddy field Inspection of the engine found the compressor, turbine, accessory gear box and reduction gear box to rotate. The chip detector was examined and was found to be free of contaminants. The fuel lines to the engine, the fuel filter and its respective fuel bowl was unobstructed. No external contaminants were observed to be present on the igniter. The engine pneumatic lines were in place and did not possess any indications of leakage. One blade of the first stage turbine rotor and two blades of the power turbine were fractured. The compressor and turbine housing exhibited twisting without any localized outward deformations or punctures. The fuel-oil heater was found to be intact and upon internal examination a 50/50 ratio of fuel to water was estimated to be present. The high pressure fuel pump and fuel control units were examined by Pratt and Whitney under the supervision of the Transportation Safety Board of Canada and no anomalies were noted. The Transportation Safety Board of Canada concurs with the report which states, 'Dynamic tests to the Fuel Control did not identify any indications that would have precluded appropriate engine performance and goes on to say, 'The gear stage was observed to be in good condition when ignoring the damage created during the suspected field inspection of the pump'. Metallic debris was found to be present in the field inspection of the high pressure fuel filter bowl and is considered to be normal in this area.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.

The factual record from the NTSB's investigation tables, in plain English

Pilot

  • Certificate: commercial pilot
  • Ratings: multi-engine land; single-engine land; instructor: airplane single-engine; instrument: airplane; rotorcraft: helicopter
  • Flight time: 20,000 hours in all; 3,000 in this make and model; 150 in the last 90 days; 30 in the last 30 days; 19,600 as pilot in command; 600 on instruments
  • Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
  • Seat: ctr

The aircraft

  • Airframe total time: 5,921 hours
  • Last inspection: 100-hour inspection, June 17, 1998; 26 hours since
  • Maximum gross weight: 5,200 lb
  • Seats: 1
  • Landing gear: fixed
  • Engine: P&W PT6-A20 (turboprop); 0 hours total

The flight

  • Departed from: OING Mount Vernon IN at 12:00 pm
  • Flight plan: none
  • Runway 0

Weather at the time

  • Light: daylight
  • Wind: from 110° at 7 knots
  • Visibility: 10 statute miles
  • Sky: clear
  • Temperature: 79°F (26°C), dew point 64°F (18°C)
  • Altimeter: 29.00 inHg
  • Observation at 10:54 am from EVV

Injuries

FatalSeriousMinorNone
Crew1

Documents from the investigation the NTSB's docket: the evidence folder behind the report

The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.

Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.