A husband and wife from Plettenberg Bay escaped uninjured after their light aircraft had to make an emergency beach landing on Wednesday.
They were flying from Port Elizabeth to George at the time.
The NSRI's Craig Lambinon says their duty crew at Jeffrey's Bay was activated and asked to respond to the Van Stadens River mouth after the plane had to make the landing.
He says engine failure is suspected.
Following consultation with investigators from the Civil Aviation Authority (CAA), the aircraft was moved to safety nearby to be recovered.