Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Landed As Precaution
Aircraft; Procedure
On a functional check flight for aircraft coming out of heavy maintenance. We had completed climb; high altitude; and descent functional checks and had entered holding at 16;000 feet to complete the low block checks. The first check was the alternate/secondary flap check. Flaps/slats operated normally during the alternate extension to 20 degrees. Once at 20 degrees; the alternate system is turned off; the center hydraulics is turned off and the normal flap handle is moved from 20 degrees to 30 degrees. The aircraft senses the loss of hydraulics and is supposed to drive the slats and flaps to the selected position. The slats drive first. The slats sense a skew or jam and did not drive out. This resulted in a SLATS DRIVE message. As pilot monitoring; I called out the failure and then positioned the flap handle to match the current flap position of 20 degrees. We [notified ATC] for the flight control failure and made a 20 flap landing with crash; fire; rescue standing by because of the increased airspeed for the landing. There had been noted corrosion issues with the slat rollers on our 787 fleet. The lubrication cycle has been halved in an effort to address the issues. We are still seeing corrosion with the rollers. Boeing as manufacturer and airline operators need to investigate possible replacement of slat rollers with materials that won't have the corrosion issue.
B787-800 Captain reported a slat drive malfunction during a functional check flight. Captain also noted there appears to be a corrosion issue with the slat rollers on 787 aircraft.