US investigators probing a wrong-runway landing by an Embraer 170 at Chicago O’Hare have disclosed that the crew had encountered problems autotuning the ILS localiser frequency.
The Envoy Air flight, inbound from Norfolk, had been conducting a visual approach to runway 10C on 25 September.
This was different to the runway 27R approach initially planned by the pilots who, as then flight progressed, subsequently expected 9L and then 10R.
After contacting O’Hare approach control, the crew was assigned runway 10C.
But when the captain programmed the flight-management computer with the ILS for 10C – as a back-up to the planned visual approach – the crew did not receive an ILS identifier.
The captain reloaded the approach and manually tuned the frequency in an effort to resolve the problem, but was unsuccessful.
According to preliminary findings from the National Transportation Safety Board, the aircraft was instructed to turn onto a 060° heading to intercept the 10C localiser – which the crew initially read back as 090° before being corrected.
When the captain contacted the tower, and stated that the aircraft was on the visual approach to 10C, the flight was cleared to land. The aircraft touched down, however, on the parallel runway 10L which lies 370m to the north of 10C.
None of the 68 occupants was injured, and the aircraft (N772MR) was undamaged – the tower controller had noticed the misaligned approach and co-ordinated with the runway 10L controller to allow the Embraer to land, because there was no traffic conflict.
The crew was not notified of the error during the approach, and the pilots had not told controllers that they had been unable to tune the localiser.
Investigators have yet to reach conclusions on the cause of the error. The cockpit-voice recorder was overwritten, the inquiry states.
