Recent content by Kurt Zierhut

  1. Kurt Zierhut

    Multiple alternator failures

    That seventh diode may be in place but I never saw a massive battery short. There is also a principal in most aircraft systems that cars rarely do. That is a "battery disconnect relay" and an "alternator disconnect relay". That's why those system have a switch for each. Shutting off one or the...
  2. Kurt Zierhut

    Multiple alternator failures

    Here is (near) the end of the long alternator story. We had a repair shop look at the near-new-but-failed alternator. They immediately found shorted windings on the stator. They saw loose and poorly completed windings. This repeated (3 times) failure of an alternator is due to poor construction...
  3. Kurt Zierhut

    Multiple alternator failures

    If a diode in a three-phase-bridge shorts, it immediately gets an unlimited current thru the opposite diode. The result is that both diodes are burned open. That current is from the alternator in parallel with the battery so it burns open REALLY fast. The cause of the problem I am seeing is one...
  4. Kurt Zierhut

    Multiple alternator failures

    We have been over the aircraft wiring now twice. We do not see any intermittent source of high current/short. The resistance thru slip rings to rotor is correct and constant. If an short kills diodes when 6 are working, we would see last 2 fail even faster but last two are working now for a...
  5. Kurt Zierhut

    Multiple alternator failures

    No prop work has been done in the last year; since before this issue started. This isn’t the clutch. Diodes inside are damaged.
  6. Kurt Zierhut

    Multiple alternator failures

    I have been doing a lot of testing for the last two weeks. The alternator seems to be putting out about the right voltage and current for the system. But I just tested the diodes inside and 4 of 6 are open. Only one pair of diodes are ever conducting. The result is high ripple current and a...
  7. Kurt Zierhut

    Multiple alternator failures

    Thanks for the inputs. There is a engine/electrical monitor system installed that shows voltage and currents. When the Alt light is solid on, the indicated buss voltage is still about 28.5V, battery current is +2 A, and alternator current is 22 A. This seems a contradiction but the monitor...
  8. Kurt Zierhut

    Multiple alternator failures

    I have a 2000 Piper Saratoga that is now on its third alternator failure in three months. The folks making the alternator (Hartzel) cannot give us a solution. The local FBO keeps replacing the alternator. The failures usually starts with a buzz or whine heard in the headsets, then progresses to...
  9. Kurt Zierhut

    XM receiver won't get TAF

    Well... Here is what seems the end of the story. The was an old SL for the 525C from a few years ago. I didn't pay attention to it as it described a problem we were not having. That was a "timeout message while processing XM downloaded data". It seems the XM data block has grown over the years...
  10. Kurt Zierhut

    XM receiver won't get TAF

    Has anyone experience problems getting terminal forecasts (TAF) with the ProLine-21 XM weather receiver? I saw this occasionally last year and more this year. On four flight legs in the last week, I got no TAF from the XM receiver. They all said "no data available". I make a point of trying as...
  11. Kurt Zierhut

    How much longer to fix the 737 Max

    Well... We can read the reports. The cockpit voice recorder included the unexpected sound of hail on the windscreen. Subsequently a pilot said "weather radar not operating".
  12. Kurt Zierhut

    How much longer to fix the 737 Max

    That's a summary description. An FAAsafety.gov event about 2 years ago spent 2 hours describing all that went wrong with that Air France flight. It started because the pilots left weather radar in "TEST". They flew into a thunderstorm. Then, slow and at high AOA, they flew into a serious...
  13. Kurt Zierhut

    How much longer to fix the 737 Max

    There was a case of an Air-France Airbus some years ago flying from Brazil to France. Somewhere over the ocean, it encountered an (unexpected!) thunderstorm. A combination of weather and flying decisions lead to a full stall of the wing and a full stall of the tail. At the point, the plane was...
  14. Kurt Zierhut

    How much longer to fix the 737 Max

    I wonder how many of you have started reading the published LionAir report. The portion where they review all of the events sequentially is scary. It gives the impression of a seriously mismanaged cockpit. CRM does not seem to be trained there. These guys were calling for checklists and getting...
  15. Kurt Zierhut

    Dale Jr. Crash

    I just got back from the Bristol race. About once a year we look at Elizabethton (0A9) but decide it is too short. I also just talked to a pilot friend who happened to call Dale Jr Enterprises last month looking for a job. They were rude and said they had all the pilots they need.
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