Incident Overview
On 1 February 2014, a Boeing 787-8 operated by PLL LOT was conducting an ILS approach to runway 11 (DS11) at Warsaw Chopin Airport (EPWA) when the crew received SPOILERS and NOSE WHEEL STEERING fault indications. The crew discontinued the approach and performed the appropriate checklist. Subsequently, they conducted an approach to runway 15 (DS15) due to more favorable wind conditions (140° at 19 knots). During taxi, differential braking was used for directional control.
Post-Flight Actions
After landing, the crew made an entry in the LDP-60 logbook and handed the aircraft over to MAEL Monarch maintenance personnel. The maintenance team inspected the spoilers and found no discrepancies. A deep crack was discovered on wheel number 5, which was replaced. The nose wheel steering system was checked, and the LWS (likely a steering control unit) was replaced and adjusted.
Analysis and Probable Cause
Analysis with 787 fleet pilots indicated that the NOSE WHEEL STEERING fault indication can occur when both pilots simultaneously operate the nose wheel steering tiller for more than 10 seconds. The most probable cause of the incident was determined to be simultaneous use of the nose wheel steering tiller by both pilots for longer than 10 seconds.
Preventive Measures
The operator took the following preventive actions:
- Replaced the line-replaceable unit (LRU) of the nose wheel steering system.
- Recorded the event in the Safety Management System (SMS) database and classified it according to PLL LOT criteria. It will be included in safety performance indicators monitored under the Safety Management Manual.