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Hello Everyone, I fly a Rans
S7S with a 912 ULS. Today
While flying I was experiencing oil smoke in the
cockpit and oil covering the
Windshield. Additionally I was seeing a loss of oil pressure. I shut down the engine inflight and made it
Back to my home airport.
After removing the cowling
and replenishing the oil supply I restarted the engine
I had a high pressure steam oil coming out of the oil pressure switch. Aircraft has 320 TT. What a mess. I contacted Lockwood and sent the some photos. The
Switch from what I can see
drives the Hobbs and ? I have a new on the way. I would like to install a chrip
Alarm similar to a backup
Alarm on heavy equipment.
Does anyone have any ideas
Were to tie in the chrip alarm? Thank you for your
Help . Bob

PS . Lockwood was great and very concerned over
This incident. They indicated
Seeing it once before.
Af
  • Re: Loss of oil pressure in flight

    by » 7 years ago


    This works for an LED Light. (Attached)
    When the Oil Pressure dies, The Switch Opens, the Hobbs Stops, and the light comes ON.
    With Good Oil Pressure, the Switch closes, the Hobbs Runs, and the light extinguishes.

    A Beeping Alarm may be an overkill response to your recent trauma.
    A Red Low Oil Pressure Light near the Flight instruments would suffice.
    But if you insist...

    Something like THIS will wake the dead and blind them. (Kidding) It Beeps and Flashes.
    You may want to add a switch to mute the alarm. It can get obnoxious after 10 seconds.

    You can reduce the resistor size down as low as 220 ohms (1/2W) if needed.
    Any diode in the 1N4000 series will work.
    Alarm.PDF (You do not have access to download this file.)

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Clicking the "Thank You" is Always Appreciated by Everyone.


  • Re: Loss of oil pressure in flight

    by » 7 years ago


    Bob,

    Could you please supply the manufacturer and model number of the oil pressure switch? Could you also tell us how (what part of the switch) failed? I am putting in an oil pressure switch to turn off my auxiliary fuel pump when the engine stops, so I am interested in avoiding using a switch that is known to fail (if possible).

    Ken

  • Re: Loss of oil pressure in flight

    by » 7 years ago


    Hi Ken, the 3 prong switch the failed only has
    The number 113 on it.
    The three prongs are encapsulated in a plastic
    Mount. One of the prongs became loose (assumption) causing a direct hi pressure stream of oil to hit the cowling
    And flow aft causing the smoke and loss of oil. I have been working with
    Lockwood and this only the 2nd reported case.
    The new switches are made by Honeywell. I will
    Keep you updated.

    Bob

  • Re: Loss of oil pressure in flight

    by » 7 years ago


    Thanks Bob. Would appreciate the Honeywell part number if you have it. The switch that I have and planned to install was Carter A68301. Pics attached.
    opswitch1.jpg (You do not have access to download this file.)
    opswitch2.jpg (You do not have access to download this file.)

  • Re: Loss of oil pressure in flight

    by » 7 years ago


    Hi Ken, I ordered a Holly
    Pressure switch only because it's encapsulated in a metal
    container and has screw
    connections. Summit
    Racing has them on their
    Website. I am no longer
    Comfortable with the standard pressure switch. Regards, Bob

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