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ALT Trips and Unfinished Landing Gear Cycle

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matt.lehtinen

Commercial & CFII - ASEL, Owner PA18R-201 N533PU
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Folks I’m a new member just purchased a 1988 Arrow III N533PU. Just read this string and the previous article. Since buying in December the alt would periodically trip sometimes 14 hours in between sometimes 3 times in an hour. Each time cycling the ALT switch fires the alternator back up. Bus voltage 13.7-8 when loaded up and at cruise. Recently a slew of new confusing issues have arose:
Last week I went to start the engine (with both switches on) and “click” no crank. Attached ground power and she fired up. It happened to be cold so I chalked it up to a bad battery. I went flying and after 3 touch and goes the gear would not come all the way up, and the Amp meter was flickering and then falling back to a normal cruise load with the gear unsafe light still on. Took it to the shop and asked them to replace the battery and troubleshoot the gear. The shop testing the hydraulic pump pressure: in spec; After buying a new hydraulic pressure switch it did not resolve the issue. Bench tested the old one and it was in spec. Put the old one back in same issue. Finally bled the line lubricated everything and the gear came up. I took delivery and went flying 3 cycles in the pattern same issue. Gear comes up if substantial time in between cycles but gear will not finish coming up and hydraulic pump shuts off (indicated by reduction in amp load). If cycled in a short time. Finally got stranded last night after a 1.1 hr cross country with a “click” dead battery again trying to return home (starting with master and alt switch on which practice I will change.). These all seem to me as related and not a gear system (pump and pressure switch) but some sort of weird electrical issue that is draining the battery and preventing the hydraulic system from finishing its cycle. See attached pics from cruise flight loaded up with alt on and off. How could a new battery drain dead? Thoughts on root cause of the gear?
In cruise flight the system appears to be fine. Here it is loaded up after I had to be jumped to start the engine
4D2A9CA2-FF95-4B69-B147-8FC3D72C2CE9.jpeg
DB307578-51B9-4CEE-A39E-D5F7B82F6320.jpeg
F99E9B23-DA08-4A81-97AE-587F9E097270.jpeg

Here is with ALT off in cruise
8D052924-6876-407F-A4F9-A022AC1516E1.jpeg
E2F2BA49-BCF4-4217-9FC7-F0167568CDC7.jpeg

Here is a stuck gear up cycle notice the amps at the bottom

 

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