The pilots of a Flexjet Bombardier Challenger 350 involved last month in a runway incursion at Chicago Midway International told investigators that they did not recall seeing the hold short line and failed to recognise the runway as distinct from the taxiway.
The business jet entered the runway without authorisation from air traffic control (ATC), prompting a Southwest Airlines-operated Boeing 737 to perform a go-around, according to a preliminary investigation released on 18 March by the US National Transportation Safety Board (NTSB).
The NTSB investigation finds that the 737 and the business jet maintained a lateral separation of just 61m (200ft), based on the approximate location of each aircraft’s GPS antenna.
The near-miss occurred around 08:50 Chicago time on 25 February – with the 737-800 in-bound from Omaha aborting its landing in videos widely shared on social media – and amid heightened aviation safety concerns following several high-profile accidents.
The flight crew of Southwest flight 2504 told investigators that approach to runway 31C was uneventful, with the autopilot engaged until about 500ft above ground level.
“As they continued the approach, both the captain and the [first officer] visually surveyed the airport and noted seeing a general aviation aircraft taxiing on a surface perpendicular to their runway and assumed it would holding short of runway 31C,” the report says.
The first officer heard “the aircraft audible 100ft call” and realised that the aircraft was not holding shorting, and called for a go-around. The captain executed the manoeuvre ”smoothly and without incident”.
The NTSB says the Flexjet pilots were confused by ATC instructions, which they initially read back incorrectly. “However, the ground controller immediately reissued the instructions and received correct feedback.”
The flight deck crew of the business jet told investigators that the sun impeded visibility on the right side of the Challenger 350 and they “did not recall seeing hold short/pavement markings or any other signs”.
“They further stated that runway 13R/31L appeared to have very similar width to taxiways and they had not recognised it as a runway,” the NTSB says.
Both pilots reportedly looked left and right and did not see the inbound Southwest 737 on final approach.
ATC instructed the business jet to hold short of runway 31C but the transmission was not acknowledged.
Following the near-miss, ground control informed the pilots they had crossed runway 31C and ”provided a number to call for possible pilot deviation”. The captain called for an assessment of well-being before continuing the flight, departing roughly 25min after the runway incursion.
“The rest of their flight was uneventful,” the NTSB says.
The report notes that the cockpit voice recorders on both aircraft were overwritten.
