DC-10 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Distraction; Troubleshooting
Aircraft Equipment Problem Critical
Aircraft Aircraft Damaged; General Maintenance Action
Aircraft; Procedure
Out of FL200; [we] heard loud noise and moderate vibration. We assumed that the air driven generator (ADG) had deployed. Upon arrival at the gate; Maintenance informed us that the nose gear doors were open. We never received any alerts or indications of gear doors open or gear extended. Maintenance later provided this assessment of the damage: found the following items broken: on right aft door the aft bracket assembly that attaches to the strut is broken allowing the aft door to hang loose on the hinges (ref IPC 32-36-01-01). On the left forward door the rod end for the forward door link broken (IPC 32-36-01-01). Also on left forward door; the aft support rod; as well as the aft three hinges are broken (52-81-05-01). Suggest engineer investigation of failed parts to determine adequacy of inspection procedures and interval on nose gear doors.
The Reporter suspects that the forward door actuator rod which attaches to the door with an eyelet failed first then allowed turbulent air to tear the aft door hinges; opening that door also. The indication from the cockpit was simply a vibration which the Captain associated with a ram air turbine; and as the aircraft was slowed the vibration ceased. There as no visible external door damage. The reporter did not know what the inspection cycle on these doors is or if this is an aging aircraft related issue.
A DC-10's right aft and left forward nose gear doors had brackets and hinges fail in flight which allowed those two doors to open with no indication except for an unusual vibration.