What happened
Following takeoff, the flight crew experienced difficulty retracting the landing gear. To resolve the issue, they manually bypassed the landing gear anti-retraction system. During the climb, the crew discovered that the cabin pressurization and takeoff warning systems remained in ground mode.
Following procedures in the Quick Reference Handbook (QRH), the pilots pulled the Ground Control Relay circuit breakers, which caused the cabin pressurization and takeoff warning systems to begin operating in flight mode. The remainder of the en route flight was uneventful.
Prior to touchdown, the crew decided to reset the circuit breakers. While on short final approach, the captain reset the Ground Control Relay circuit breakers. This action caused the ground spoilers to activate, leading to a rapid descent. The aircraft subsequently struck the ground tail first in the runway approach light area.
The investigation
Investigation of the nosegear shock strut revealed it was underserviced and underinflated for cold weather operations. Because of this, the strut did not extend sufficiently to actuate the ground shift mechanism. This failure prevented the release of the landing gear lever anti-retraction mechanism and failed to shift the aircraft systems from ground mode to flight mode.
Regarding the procedures used, the QRH abnormal procedure for resetting Ground Control Relay circuit breakers was located in the "Approach and Landing" section. However, the Aircraft Operating Manual (AOM) specified that these circuit breakers should be reset during taxi. The crew stated they had not referenced the AOM, nor did they notify the company of the in-flight irregularity.