Cessna T210 N1237M accident near Flint, Michigan

Probable cause

The failure of the nose landing gear actuator hydraulic hose, which resulted in the loss of hydraulic fluid and hydraulic system pressure and a subsequent gear-up landing.

NTSB analysis

The private pilot reported that, after takeoff for the cross-country, personal flight, he attempted to retract the landing gear and noticed that the gear motor continued to operate longer than normal and that the sound had become abnormal toward the end of the retraction sequence. The pilot subsequently saw that the right main landing gear (MLG) had not fully retracted and was hanging about 45° rearward. He could not see the left MLG. The pilot attempted to address the gear issue for more than 20 minutes by completing the emergency procedures checklist; however, although the nose landing gear (NLG) had extended, the MLG did not respond, so the pilot continued to the destination airport. Before landing, the pilot again attempted to extend the landing gear. During a flyby, an air traffic controller confirmed that both MLG were not extended. The pilot subsequently conducted an emergency landing with the NLG extended and both MLG partially extended. Upon landing, the airplane spun about 180° and then came to rest on the runway, sustaining substantial damage to the right horizontal stabilizer and elevator.

During postaccident examination of the airplane, the NLG well was found partially covered in red hydraulic fluid, no hydraulic fluid was found on the reservoir dipstick, and an NLG actuator hydraulic hose was found damaged. During a functional test of the hydraulic system, the emergency gear extension handle was actuated in an attempt to extend the MLG; however, after 10 to 12 pumps, hydraulic fluid sprayed from the damaged hose; the system could not build pressure, and the MLG would not extend. The damaged hose was replaced, the emergency gear extension handle was actuated, and the MLG extended and locked normally.

According to a service bulletin issued 17 years before the accident and based on the maintenance criteria for the hydraulic hose part number, the hose should have been replaced with an updated hose. However, about 13 years before the accident, the hydraulic hose was replaced with the original part number rather than with the updated part number. The hydraulic hose failed during the accident flight when the pilot attempted to retract the landing gear after takeoff. It is likely that, during annual inspections subsequent to the hose replacement, the hose was treated as an "on-condition" part since it had not been replaced with the new hose.

It is likely that most of the hydraulic fluid was pumped out of the damaged hose during the pilot's troubleshooting attempts, which led to a loss of hydraulic system pressure and prevented the MLG from fully extending or retracting and resulted in a gear-up landing.

Text from the NTSB. Open the NTSB docket for CEN19LA059 for the full record.