Douglas DC 9 83 N425NV incident near Westfield, Massachusetts

Probable cause

The air traffic controller issuing the aircraft a clearance to land while there was a vehicle authorized to be on the same runway. Contributing to the incident was the air traffic controller's decision to not simulcast the local control and ground control frequencies, and, the reduced visibility at the airport as a result of the weather.

NTSB analysis

The air traffic control tower was operating with all positions combined and the local controller provided approval for an airport vacuum truck to conduct runway sweeping on the first 4000 feet of runway 02. Also operating on the airport movement areas were several other airport and state organization vehicles. The weather was 3/4 statute mile visibility with a ceiling of 200 feet overcast and the local controller could not visually observe the vehicles on the runway. In accordance with standard operating procedure, the local controller used a red "runway unavailable" memory aid to assist with remembering that the vehicles were on the landing surface. As several of the vehicles began to clear the runway, the local controller removed the red memory aide. The vacuum truck remained working on the runway. A short time later, the air traffic controller cleared the flight crew of an MD-83 aircraft to land on runway 20 while the vacuum truck was still on the approach end of runway 02.The aircraft landed and stopped about 200 feet from the vacuum sweeper which was still on the runway.

The local controller was operating with combined ground and local positions but did not combine the ground and local radio frequencies. The airport vehicles were communicating with the controller on the ground frequency and were unaware of inbound air traffic communicating with the controller on the local control frequency.

Text from the NTSB. Open the NTSB docket for OPS17IA003 for the full record.