Clarity has yet to emerge as to why a Southwest Airlines Boeing 737-800 was not aligned with the runway during final approach to New York LaGuardia, following a service from Nashville.

The aircraft, arriving as flight WN147 on 23 March, had already conducted one missed approach to runway 4.

Its crew informed LaGuardia tower controllers that they had opted to go around because the aircraft had been “too fast, too high with the tailwind”, according to air-ground radio exchange archived by LiveATC.

The aircraft was vectored for a second approach to the same runway.

Meteorological data from LaGuardia indicates weather conditions including low overcast cloud, with a base of just 600ft, reduced visibility, and winds from the northeast.

The Southwest 737 carried out an ILS approach to runway 4, with its crew receiving landing clearance and a runway visibility update.

It had been sequenced immediately behind a JetBlue Airways Airbus A320 whose crew chose to execute a missed approach, informing the tower that it appeared to have encountered “some windshear”.

Southwest 737-800-c-Max Kingsley-Jones

Source: Max Kingsley-Jones

Southwest operates an all-737 fleet including some 200 737-800s

About 3min later an urgent go-around instruction was directed at the Southwest aircraft, which was instructed to fly the runway heading and climb to 2,000ft.

Tower controllers then asked the crew why the aircraft was “not on the approach”, to which the crew responded that they were “trying to work things out”.

While the extent of the deviation has yet to be confirmed, the air traffic control exchange captured a remark, apparently from the tower, that the aircraft “was not aligned with the runway at all – he was, like, east on final, he was not going to land [on] the runway”.

Preliminary ground-track information – which has not been confirmed – suggests the aircraft may have been some 400m to the right of the approach path, having been aligned during its previous go-around. Its proximity to the 230ft control tower and terminal buildings, which are situated about 500m right of the runway centreline, is unclear.

After the go-around the flight diverted to Baltimore Washington.

The crew of the JetBlue A320, which conducted its own second approach a few minutes later, was informed of winds from 080° at 14kt, and advised by the tower to use caution because a previous arrival was not aligned with the runway.

“We are reviewing the event as part of our safety systems,” says Southwest Airlines. It states that the aircraft diverted to Baltimore after “encountering turbulence and low visibility” at LaGuardia, returning to the New York airport after a “brief layover”.

FlightGlobal has sought comment from the US National Transportation Safety Board.