Casualties unknown

Aircraft Hydroplanes Off Runway After Landing in Heavy Rain (N1846U)

Chicago, IL, US

On July 19, 1989, a Mcdonnell Douglas DC-10-10 (registration N1846U) operated by United Airlines was involved in an aviation accident near Chicago, IL. Investigators recorded the probable cause as: The pilot's failure to maintain directional control during the landing rollout due to hydroplaning, which was facilitated by standing water on the runway and worn runway grooving. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 4 related events involving the same aircraft type or operator are linked below.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 2026-06-10Data APIEditorial standards

An aircraft hydroplaned upon landing and exited the runway due to worn grooves and standing water following significant rainfall.

What happened

The aircraft experienced a loss of directional control after touchdown, hydroplaning along the runway surface. This loss of traction caused the airplane to run off the end of the paved surface. A subsequent inspection of the runway revealed that the grooving designed to channel water was worn down to the point of being nonexistent along the specific track where the aircraft landed. Additionally, large areas of standing water were present on the runway surface at the time.

The investigation

Investigation of the site conditions indicated that the airport had recorded 1.28 inches of rainfall during the four-hour period immediately preceding the incident. The combination of this significant precipitation and the degraded runway grooving contributed to the formation of standing water, which facilitated the hydroplaning event.

Findings

The primary factor in this incident was the aircraft's inability to maintain braking effectiveness due to hydroplaning. Contributing factors included the worn runway grooves that failed to drain water effectively and the standing water on the runway surface. The weather conditions, specifically the heavy rainfall, created a hazardous landing environment.

Probable cause

The pilot's failure to maintain directional control during the landing rollout due to hydroplaning, which was facilitated by standing water on the runway and worn runway grooving.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001213X28762. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.