ICAO should consider stronger standards for centerline lighting on wide runways because of the key role the visual cue plays in helping pilots avoid runway excursions, the Australian Transport Safety Bureau (ATSB) says.

ATSB’s recommendation, issued May 15, came out of an investigation into a December 2016 runway excursion by a Virgin Australia Boeing 737-800 at Darwin International Airport. Nearing the end of a flight from Melbourne, the aircraft was cleared to land on Darwin’s Runway 29 at about 11 p.m. local time. Thunderstorms were in the area, but the crew believed they would touch down without passing through any rain.

As the aircraft neared the threshold of Runway 29, at about 270 ft. above the ground, the captain disengaged the autopilot. Seconds later, the aircraft passed through heavy rain and encountered a “light but increasing crosswind,” the report said. The aircraft drifted to the right and touched down 21 m (69 ft.) to the right of the runway centerline. 

Three seconds after touchdown, the aircraft’s right main gear departed the runway. The aircraft traveled about 400 m before the crew could get the right main gear back onto the runway, running over six edge lights along the way. Once back on the runway, the aircraft taxied to its assigned gate and passengers disembarked.

Investigators determined that the absence of runway centerline lights likely hampered the crew’s ability to recognize the drift and correct it. Darwin’s Runway 11/29 is 3,354 m long and 60 m wide, and is the only runway in Australia wider than 50 m that does not have centerline lights.

ATSB sought information on similar incidents linked to runway misalignment around the world and found 15. Each occurred at night, in poor visibility and on runways without centerline lights. Eleven happened on runways that were at least 50 m wide.

“Category I runways that are wider than 50 m and without center lighting are overrepresented in veer-off occurrences involving transport category aircraft landing in low-visibility conditions,” ATSB said. 

ICAO’s Annex 14, which provides airport design standards, recommends centerline lighting for runways at least 50 m wide that conduct Category I ILS approaches. ATSB suggests ICAO “review the effectiveness” of this recommendation and consider upgrading it to a standard—essentially a requirement that countries are expected to incorporate into their own regulations.

ATSB’s review of global runways found about 30% of them are at least 50 m wide. The report did not say how many lack centerline lighting, though ATSB's review found that “the busiest runways tend to be equipped with” it.

ATSB also urged Darwin to consider developing additional visual cues that would help pilots. While centerline lights would be the preferred option, Runway 11/29 has an arrestor cable, and officials at Darwin—a joint-use civilian-military base—say that using the cable could damage centerline lights and create foreign object debris issues.

ATSB also noted that additional guidance to flight crews on Darwin’s visual cues would be valuable. Virgin Australia has developed some for its pilots, the agency said.

Sean Broderick, sean.broderick@aviationweek.com