The pilot reported that, during takeoff from the airport in Denver, the Mooney M20F’s door opened. During the climb and on raising the landing gear, he failed to receive the gear “UP” light.
The passenger attempted to close the door while the pilot recycled the landing gear.
The pilot reported that the gear had likely not retracted based on the airplane’s failure to climb and gain airspeed as it would have had the gear retracted.
He decided to return to the airport and contacted the air traffic control tower to visually assess the gear position. While maneuvering for the air traffic control tower to verify the gear, he continued to cycle the gear up and down, receiving no indications of a change in the gear position.
The pilot reported the floorboard landing gear position indicator showed “GEAR DOWN” giving him the indication that the landing gear was down.
The air traffic controller advised the pilot the gear appeared to be in the down position and cleared the airplane to land.
The airplane touched down near the 1,000-foot marker on the runway on the two main wheels. A “split second” later, the right main and nose landing gear collapsed, and the airplane slid off the right side of the runway, hitting a runway light with the right wing.
The right wing sustained substantial damage.
A post-accident examination of the landing gear showed the landing gear motor would engage for about five seconds and then stop, leaving the landing gear in an intermediate position. A subsequent bench test of the landing gear motor resulted in the motor failing to engage or move, indicative of it being inoperative.
Probable Cause: Failure of the landing gear motor, which prevented the gear from extending fully to the down and locked position, which resulted in a gear collapse on landing and a subsequent loss of directional control.
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This October 2020 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
Mechanics should know, and pilots should aware, that certain critical-to-flight components have a fairly well known life to failure. [ we all know vacuum pumps can be expected to fail within 500 hrs ]
All of the dc brush type motors used in gear, flaps, heaters, and also alternators will wear the brushes within 1,000-3,000 hours , that will cause the motor to fail to operate.
The time to fail depends on how many hours that the gear and flap motor is operated.
Alternator brush wear is due to mechanical and electrical wear – time and load current.
It may be inconvenient to disassemble what appears to be a normally operating motor.
But it is much lower cost to repair a motor than to rebuild the gear and overhaul a prop strike engine.
aircraft does have a manual gear extension procedure
no mention of that
This is a 46 yr old aircraft with 3,286 hours on it. So I’d expect that all the dc motors in the aircraft would be needing service, which is usually just brushes and an $800 bill.
The gear motor, the flap motor, and also the alternator won’t run much past the 3,000 hrs in-service time. With a lot of pattern work, the gear and flap motors will wear faster, maybe as little as 1,000 hrs.
Then, there is inspecting the limit switches so that the motor shuts off before hitting the hard stops and stalling the motor, which will quickly overheat and destroy itself.
So, due to lack of maintenance and repairing/replacing worn parts, the aircraft is now needing $10s of thousands of repairs.
Maybe insurance companies should consider paying for some low cost repairs to save on huge gear up repair costs ?
Oh, and now the aircraft has a lower value due to the gear up crash in the logs.
This is an interesting idea that Jim brings up. Some insurance companies offer to cover a certain amount of expenses for moving an airplane out of the path of a hurricane. Its worth it to them to pay a little to avoid paying a lot. This could hold true for certain maintenance items as well. If they were willing to help pay for inspections or PM’s of certain key components, it may encourage pilots to have this work done. Alternatively, they could offer discounts on hull insurance if certain key maintenance activities are completed and documented. I’m not saying they should pay for oil changes, but I’m sure they are aware of the more common causes of mechanical failure induced claims and could help mitigate these issues with a little incentive. It’s not much different than offering a lower premium for pilots who receive additional training or an instrument rating.
No.
Because what ever the insurance company pays out this year, they simply recoup from their policy holders (customers) next year.
Watch what happens after this hurricane Ian.
Not sure what this has to do with what I am saying. Yes, we all will pay more next year due to the hurricane. However, they could still offer discounts for proper maintenance practices just like they do for certain pilot proficiency activity.