one possible reason for the extended pole could be snow clearance, just a thought.
just had a look at this from Boston earlier this year
they are using marker poles to alert the snow ploughs to the lights location
I wonder why in the USA Globally they sell Low/Medium Intensity Airport Lights with Incandescent Lamps where in the UK they are High Intensity Lights, also what is interesting on Small Airports they seem to mount the Lights on poles almost 3 feet high, which could be damaged by Aircraft Strike, anyway I have bought one off the US E-bay and it came with the Long Pole
This Light has a Dual Red Clear Lens the Red Side is to warn Pilots that they are approaching the End of the Runway the Clear is used as a standard Runway light for the Opposite Direction, as you can see it is mounted on one log pole
Last edited by sailormoon_01_uk; 03-12-2011 at 21:22.
one possible reason for the extended pole could be snow clearance, just a thought.
just had a look at this from Boston earlier this year
they are using marker poles to alert the snow ploughs to the lights location
Last edited by kebecker; 04-12-2011 at 22:20. Reason: another thought!
Makes Sense, I think it's common for Runway and Taxiway Lights to me mounted on long stems/poles see photos
All the Best
Colin
US Runway Threshold/End Light
US Taxiway Edge Light
In the UK there are low intensity lights aswell as high intensity, so it isn't only the US. It's entirely dependant on the category and use of the airfield.
Small airports you may see threshold lights on a longer pole, but edge lighting is usually elevated only a little. I've never seen a long pole near the runway unless it were threshold on small airfields and of course, the approach.
From the distance, that looks like the normal height of an elevated taxiway light, which is shorter than the photo that sailor_moon has posted.
You'd be surprised though, the snow soon melts away once the lights are on and even on small use airfields such as military it's often advised to switch them on when they open the tower and leave them on all day to ensure they're clear.
There's clear to the eye, but then there's clear to the degree of coverage and spread pattern as up there, it all looks different.
Like Kebecker I also suspect that these lights may be raised for snow clearance, not every airfield clears snow like we do in the UK. As for putting the lights on to assist the snow clearance, do you know Ive never seen any station do that!
The snow ploughs/runway clearing vehicles won't de ice or clear the snow from the lights perfectly. In the nicest possible way of course, when fully understood about coverage, light spread, lighting regulations, it isn't enough to clear the lights and expect the correct pattern from above. The lights will get very warm, which is a good way to assist in clearing them and keeping them clear.
I've watched it many times on airfields I have worked at as an airfield lighting and controls electrician and it's something we advise. For example, PAPIS have what is called 'black heat', a heater circuit to keep the ice off the lenses and filters inside as they'd otherwise need to be on full for 20 mins to give the output and coverage required by the JSP.
Some interesting material in a Transport Canada Advisory Circular 302-008 relating to elevated light fixtures
ELEVATED FIXTURES
Remove snow from around the lighting fixtures as soon as possible after a snowfall so the light fixtures are not obscured. If heavy snowfalls are predicted, plant red flags or reflective sticks of enough length next to the edge lights to mark their location. The flags will help snow removal and will lessen the damage to fixtures by snow removal equipment.
When flags or sticks are used, care is taken to ensure that the installation is secure and the devices will not be released so as to become FOD on the runway or taxiway.
FAA recoomedations regarding elevated lighting in snow areas:
The height of the lights should not exceed 14 inches when located within 5 feet of the runway or taxiway edge. In snow regions, where the lights are located beyond 5 feet from the runway or taxiway edge, the lights may be raised 2 inches for each foot beyond the 5 foot point. At the 10 foot position, the lights may have a maximum height of 30 inches . The increase in height is permitted only if any overhanging part of an aircraft expected to use the runway or taxiway could clear the light by at least 6 inches when the plane’s main landing gear is located on any part of the runway or taxiway
I am sure I have seen some manufactures guidance on keeping lights moisture free in winter operations,just a case of findin it
Last edited by kebecker; 11-12-2011 at 21:24. Reason: added more detail
Hi Guys
Thanks for the update, I have bought three more Airfield Lights off E-bay one is a Butlers Light see HERE, the other two lights are GEC ZA105's Unidirectional Approach/Runway Edge Lights, they have been modified to use 12 volt 55 watt H1 Auto Halogen Lamps,
GEC-ZA105-Airport-Landing-Lights.jpg12v-55w-H1-Auto-Spotlight-Lamp.jpg
Click on Photos to Enarge
All the Best
Colin
Thread getting big. Part 2 continues HERE
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