Re: Landing Light Switch Part Number

tdrager · Post by **tdrager** » Thu Sep 25, 2014 11:34 am

'Our local EAA chapter is restoring a 12 volt Fairchild F 24. Anyone now what modern make / model of switch is used to switch on incandescent bulbs, e.g. landing light. For example the parts list, for a 24 volt version, lists an AN3018 switch. However, currents are doubled in the 12 volt version: 15 amps continuous and an inrush current in excess of 100 amps. We must procure an equivalent to the above switch if we are to meet FAA regulations and prevent smoke in the cockpit.'

Jim higham · Post by **Jim higham** » Thu Sep 25, 2014 5:30 pm

'Use the 24 volt switch and have it control a relay rather than running the high current through the switch.
Jim
F24R46A-108

Sent from Yahoo Mail on Android From:"tldrag1@gmail.com [fairchildclub]"
Date:Thu, Sep 25, 2014 at 12:34 PM
Subject:[fairchildclub] Landing Light Switch Part Number

Our local EAA chapter is restoring a 12 volt Fairchild F 24. Anyone now what modern make / model of switch is used to switch on incandescent bulbs, e.g. landing light. For example the parts list, for a 24 volt version, lists an AN3018 switch. However, currents are doubled in the 12 volt version: 15 amps continuous and an inrush current in excess of 100 amps. We must procure an equivalent to the above switch if we are to meet FAA regulations and prevent smoke in the cockpit. '

mileslong2k · Post by **mileslong2k** » Sat Sep 27, 2014 10:04 pm

'What EAA chapter is restoring the 24?

Jim Long'

tdrager · Post by **tdrager** » Sun Sep 28, 2014 6:04 am

'Found it! After many hours of searching, I finally settled on a 4 pole double throw (AKA 4PDT) switch which can handle the huge inrush currents. Each pole is rated for 7 amp lamp load and since there are four poles, it can handle a 28 amp lamp load when I parallel the connections. Our landing light will draw 15 amps at 12 volts, steady state. The part number is: MS25308-212. Since this is a military specifications, it will meet FAA regulations regarding huge in rush currents presented by the lamp load in the Fairchild, which will be at least 100 amps when the landing light switch is engauged. I ordered two of these: one for the landing light and one for the navigation lights.They were $15 each, military surplus used parts.'

tdrager · Post by **tdrager** » Sun Sep 28, 2014 6:12 am

'We are Chapter 1250, Pottstown, PA. Fred VanRyn is our president. Our goal is to have her flying in time for Oshkish 2015.'

Fred Van Ryn · Post by **Fred Van Ryn** » Sun Sep 28, 2014 8:51 am

'Great job Tim - and only $15 each - thanks!
On 09/28/14, tldrag1@gmail.com [fairchildclub] wrote:
Found it! After many hours of searching, I finally settled on a 4 pole double throw (AKA 4PDT) switch which can handle the huge inrush currents. Each pole is rated for 7 amp lamp load and since there are four poles, it can handle a 28 amp lamp load when I parallel the connections. Our landing light will draw 15 amps at 12 volts, steady state. The part number is: MS25308-212. Since this is a military specifications, it will meet FAA regulations regarding huge in rush currents presented by the lamp load in the Fairchild, which will be at least 100 amps when the landing light switch is engauged. I ordered two of these: one for the landing light and one for the navigation lights.They were $15 each, military surplus used parts. '