The left main landing gear is lodged between the engine and the body of an Embraer airplane following a rough landing at the Presque Isle International Airport on March 4, 2019. Credit: Courtesy of National Transportation Safety Board

PRESQUE ISLE, Maine — A March 2019 crash landing in Presque Isle was not the first time snow affected a plane’s ability to land.

An Embraer aircraft overran a Cleveland runway in 2007 when it attempted to land in poor visibility and snowfall. One of the landing instruments was not functioning and a snow squall made the runway invisible to the pilot, reported the Aviation Herald.  

The most recent incident in Presque Isle occurred March 4, 2019, when a CommutAir Embraer aircraft aborted its first landing due to snow, and missed the runway on its second attempt. The plane touched down to the right of the runway and bounced, skidding into a snow-covered field.

Though the National Transportation Safety Board cited pilot error in its final report on the missed landing at Presque Isle, it also detailed how snow caused landing instruments to misread the aircraft’s position.

The Federal Aviation Administration has detailed safety guidelines. But since snow can affect instrument landing systems, the agency has revised some of those procedures to help pilots, air traffic controllers and airport operators guide planes to safety during storms.

Last fall the agency called for more frequent reporting of runway and weather conditions, noting that many airports close when a storm is imminent. It also urged more frequent snow removal to keep runways as close to bare as possible.

“Following this accident, the FAA issued additional guidance to assure the quality of the localizer’s radiated signal during activities such as snow removal,” agency officials said Thursday.

Snow can change the surface area of a runway enough to affect the signals of the localizer and glidescope, instruments that show pilots where the runway is, the FAA said in its Airport Field Condition Assessments and Winter Operations Safety plan.

New safety protocols advise airport operators to report runway surface conditions and include the depth of snow, ice or slush. The reports should be issued more frequently, even if conditions haven’t changed for a period of time, to make sure pilots have the most up-to-date reports of weather and snow removal efforts.

“After snow accumulation of 2 feet, the FAA system specialist needs to start observing the condition of the localizer signal,” the revisions said.

Airport operators should also keep detailed snow removal records.

The FAA provides grants to airports for a range of safety projects, including runway construction and repair, lighting and snow removal through its Airport Improvement Program. The Presque Isle airport received a $1,074,816 grant in late 2019 to purchase two large runway snow sweepers, which brought its total to three.

The machines are like giant brooms, and sweep large amounts of snow off the runway to avoid ice sticking to the pavement, Airport Director Scott Wardwell said in September 2019.

An airport maintenance foreman reported after the landing that 1 to 2 inches of snow had fallen before the crash and that 4 to 5 inches had fallen that day. Snow removal operations kept snow depth to 1/4 inch or less on the runway, the report said.

The safety board blamed the event on the flight crew’s decision to continue landing when they couldn’t see the runway. Other factors were the first officer’s fatigue due to being sick with influenza and the failure of previous crews to report problems with the localizer, according to the 23-page report.

Both flight crewmembers said instruments indicated the airplane was aligned in the center of the runway, according to the report. Testing after the crash landing said the localizer was off by about 200 feet to the right.

Both the captain and first officer tested negative for drugs and alcohol following the incident, the NTSB said.

CommutAir had only received one report of localizer problems before the missed landing, but four reports from other pilots were filed afterward.  

Airport Director Wardwell said he had read the report, but that the FAA owns, operates and maintains the landing instrument system, which is the case at most small airports. Federal standards are in place at the airport, which is why the NTSB investigated.

“The NTSB report is very detailed, and we at the airport would just say that it speaks for itself,” he said.