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Casualties unknown

Airplane Disappears from Radar During Night ILS Approach in IMC (N7100L)

Provincetown, MA, US

On October 9, 1998, a Grumman American AA-5 (registration N7100L) was involved in an aviation accident near Provincetown, MA. Investigators recorded the probable cause as: The failure of the pilot to follow the published instrument approach procedure, which resulted in inadvertent collision with water. Factors in the accident were the dark night and low ceiling. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 2026-07-04Data APIEditorial standards

During a night ILS approach in instrument meteorological conditions over water, the airplane descended, leveled at 100 feet for 12 seconds, then vanished from radar. No mechanical failure was found; both wings sustained moderate impact damage.

Approach and Disappearance

The pilot initiated an ILS approach in instrument meteorological conditions (IMC) at night, with the approach conducted over water. The airplane tracked the localizer and glideslope for part of the approach, then entered a descent and leveled off at 100 feet for approximately 12 seconds before disappearing from radar coverage.

Aircraft Condition

Post-event examination revealed no evidence of a mechanical failure or malfunction with the airplane. Both wings had sustained moderate impact damage. The outboard portion of the left wing was not recovered.

Pilot Communications and Navigation Setup

The pilot had informed approach control that if he executed a missed approach, he would request the approach to a nearby airport. However, the navigation radio frequencies set in the cockpit did not match the instrument approach being flown, the missed approach procedure, or the planned subsequent approach to the other airport.

Controlled flight into terrain

Frequently asked questions

What happened in the 9 Oct 1998 Grumman American AA-5 accident near Provincetown, MA?

During a night ILS approach in instrument meteorological conditions over water, the airplane descended, leveled at 100 feet for 12 seconds, then vanished from radar. No mechanical failure was found; both wings sustained moderate impact damage.

What aircraft was involved and where did it happen?

The accident on 9 Oct 1998 involved a Grumman American AA-5, registration N7100L, at Provincetown, MA.

What was the probable cause of the accident?

The failure of the pilot to follow the published instrument approach procedure, which resulted in inadvertent collision with water. Factors in the accident were the dark night and low ceiling.

More accident analyses

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001211X11324. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.