Landing Light

[flat country pilot]

I need to replace a burned out landing light. Which lamp do you guys like and what is the best source for it?

Part Number 0523118-1

I am only replacing the burned out lamp and assume there is no advantage to replacing them both, just because I can.

Bill

[GAHorn]

The "official" bulb is a common 100 watt sealed beam and is made by GE under their part number 4509, available from any aircraft supplier. Other brand names using the same GE part number and specs that are sold by auto/tractor supply stores are Tung-Sol and Wagner, and they are identical as far as can be told, except they will not have that little PMA notation anywhere. (Even GE has quit stamping their packages, I've noticed, and most brands identify their 4509 bulbs as "aircraft" lights now.) Depending on where you buy it, the price will be $10-$20 each.
Installation is made by removing the screws which hold the plastic leading edge lens and frame, and unscrewing one side of the half-frame that holds the bulb. Don't lose the compression spring that's behind the half-frame which the screw passes thru. Notice that the bulb is oriented with a small alignment "tab" moulded into the backside of it's rim, which fits into a cut-out of the mounting half-frame. Notice also the number of turns required to remove the screw holding the frame that you remove to replace the bulb. If you like the existing aim-point of your landing/taxi lights, you'll want to count the number of turns it takes to remove those screws (each of the four screws will be different) so you can return them to their original depth. (The depth of those screws, in conjunction with the springs, orient the beam of the light. The original measurements for the alignment is found in the MX Library.)
http://cessna170.org/phpBB2/viewtopic.php?t=578

[flat country pilot]

Thanks George.

I didn't know I could just go to town and buy a light. I thought it would have to have some kind of traceability for the FAA. If I understand you right, It does not need the PMA notation, just needs to be a 100w 4509.

What is PMA?

I read the alignment procedure in the MX library and will try to keep the light the way it is.

After I change it, should I enter this in the logbook?

Bill

[Bill Hart]

Parts manufacturing authorization

[GAHorn]

PMA stands for "Parts Manufacturing Authorization" and is the "official" blessing we look for on replacement parts. All aircraft replacement parts should be either from the Original Equipment Manufacturer (OEM) such as Cessna... or it should be from a parts maker that has been blessed by the FAA with authorty to manufacture identical replacement parts, which are usually marked with "FAA-PMA".
PMA'd parts are made to the exacting quality controls that original parts are, and virtually all parts should be "PMA" parts according to the official wisdom and rules. I personally have a reputation for being a stickler for such matters, but if there ever was a rule I'd have few qualms about violating, it would be with regard to replacement light bulbs, especially sealed beams. (Firstly, landing lights are not a required piece of equipment on non-commercial operations, and secondly they are all virtually identical in every way. This is not to suggest that all lighting replacement bulbs are equal, however. I would not substitute a cheap chinese bulb that had a metal bayonet base for a nav light, for example. The ceramics inside that base are designed for high-vibration in quality bulbs, and cheap chinese bulbs are not durable in that regard and may break and provide an electrical short opportunity for you at night. (Also, wing-nav lights are reflective bulbs which are unavailable from autoparts sources. The correct wingtip nav lamp is a Grimes/Cessna A-7512-12 or Whelen W1290-14. Caution: Do not handle the reflective bulbs, or Halogen bulbs with your bare fingers. The oil will reduce the bulb life. If you handle the bulb with your hands, be certain to wipe the bulb with alcohol before turning it on. Don't use common rubbing alcohol as it contains glycerin.) Tail nav bulbs are not reflective, however. An automotive 1156 or 93 works very well there. In fact, the official Cessna part has superceded to another Cessna number, but if you order it, you'll receive a common GE 93., and pay twice as much for it plus shipping. The exact same bulb is a common marine lamp used in anchor lights, and is also used for many trunk/dome lights in autos.) But I'd have very little problem with other automotive bulbs in certain non-reflective applications as long as they were quality-made bulbs. The world-standard for quality is GE, but Phillips, Wagner, Tung-Sol, etc., are also good for most applications. )

Trivia: Has anyone noticed that the OEM for our instrument lighting fixtures is Grimes, ...but the OEM for the lamp/bulb inside that fixture is Mazda? Yep. It's a Mazda #67. (Which is a cheap Japanese copy of the GE 67.) The GE can be bought in a two-pack at WalMart for 95-cents, or singely at NAPA for $1.19, or in the Wagner brand at NAPA in a two-pack for $1.12 But you can buy it directly from Cessna as a PN 0713017-9 (which, by the way, is actually a GE 89.... which is also identical to a GE 87, for whatever it's worth,... for only $2.15 each.
NONE of those options will have the FAA-PMA stamp on it. (But some FSDO/FAA inspector types will insist that it MUST be in order to be utilized on an airplane. I disagree with them on that point. And they shrug and do not care to pursue it for some reason.)
Oh, the burdens of officialdom.

[Kyle Wolfe]

I've been buying the lights at NAPA for some time, but have been frustrated with their relatively short life span. (I use my landing light anytime I"m within 5 mile radius of an airport.)

I've tried the trick of aligning the element vertically instead of horizontally. The light seemed to last longer but I don't like the flood that it cast.

So I just ordered a couple of the halogen 4509s. Will be interested to see how much light they provide and how long they last.

Anyone tried these? Results?

[GAHorn]

The filament within the bulbs is sensitive to vibration when incandescent. Some higher-quality bulbs have their filaments supported by an additional wire...and some bulbs have the stanchions (the heavier wires that hold the coiled filament itself) further strengthened by a glass brace connecting the stanchions to each other to reduce expansion/flexing/vibration injury. (The tungsten coiled element will lengthen as it becomes heated to incandescence. This stresses the element similar to frequently bending the paper-clip. A stiffer stanchion will eliminate some of that and prolong element life.)
It's possible your lamp fixture is vibrating excessively contributing to short bulb life. You might consider having your prop dynamically balanced. You might also be certain your electrical leads are not taut and the bulb mounts are not binding in any way.
Quartz bulbs are also sturdier, but they cost about $75 each! While prop balancing is also costly ($150-$250 perhaps) that will also contribute to longevity in a lot of other ways. (Windshield cracking, cowling cracking, accessory life, radio/instrument longevity, etc. etc., plus the enjoyment of a smoother running engine.)

[n2582d]

Bill,
Neal, on the Cessna 120-140 website, has some good information on landing lights. See http://www.cessna120-140.org/forum/download.php?id=743

Or, if you had a bumper crop this year, you could try to get a field approval for some bright HID xenon lights. Apparently they have been able to get field approvals for these on C-172s. The downside: $550 for the conversion kit for the landing light and another $550 for the taxi light. http://www.aerovisions.com/hid/hid_pric ... conversion kits

[4-Shipp]

Bill,

You asked about replacing the remaining operational bulb at the same time. Myself, I replaced both bulbs at the same time and kept the remaining operative bulb as my spare. I fugured if one went due to age, the other might not be far behind Assuming they were both installed at the same time), and I still had a spare to keep me going in a pinch - or as it usually works out, to give to an airport mate when his/her light quits and they do not have a spare.

Bruce

[GAHorn]

The CPA issed an interesting article years ago regarding this subject, and I've searched my files and found it in a pdf file. They mention a flight school that became discouraged over the short life of their 4509 bulbs (13 volt, 100 watt, 110,000 c.p., 25 hr. predicted life) and they replaced them with 4595 bulbs (13 volt, 100 watt, 60,000 c.p., 300 hr. predicted life.)
Of course, there's nothing for free, and you'll notice the candlepower (c.p.) is less.... however c.p. versus effective illumination is not a direct ratio, (it's a square-root function) and there is only about a 25% difference in effective illumination.
Most folks don't mind the slight loss considering the years of added life (as compared to the previous weeks) in a set of bulbs. The CPA stated that the conversion to the 4595 bulb was accepted by their FAA/FSDO as a matter of safety (burned out bulbs aren't safe) with a logbook entry, presumeably as a minor alteration.

[4stripes]

I've changed the orientation of my landing lights so that the filament is now vertical instead of horizontal. I fly with my both lights on at all times in flight to improve visibilty (for other aircraft). I have not changed a bulb in over 11 years! I know it sounds too good to be true, but I tried it with amazing results. A dramatic improvement in bulb life happened just by rotating the bulb 90 degrees. My theory is that most of the filament breakage is caused by vibrating up and down. Simply turning the bulb removes the exposure to most of the vibration.
I realize the light pattern is optimal when horizontal, but they certainly work well enough (with the benefit of saving time and money). The added safety of flying with them on continuously makes me feel better too.
Cheers Eric

[Kyle Wolfe]

FYI - I just bought the GE Q4509 quartz halogen bulbs for $20.63 each (versus the $9 or so for a regular filament bulb). Figured that the few extra bucks was easily worth a try.

George, thanks for the comments about prop balancing. Have thought about that, even though the engine is smooth and I only replace lights about 1 per year. So the old bulbs are giving me a typical lifespan - they are rated for an average life of 25 hours. Just that it's a pain to do.....

The quartz halogens are said to have an average life of 100 hours.

But after reading the attachment from Gary and the 120/140 gang, I'll probably just go back to the regular 4509 when my halogens get the darkened reflectors......

[flat country pilot]

I ordered two GE 4509 from Skygeek. $8.25 per light and $5.30 for USPS priority mail. Good old Uncle Sam.

Kyle, what is this about being a pain to do?

Bill

[LEA]

I find it inadvisable to burn my landing light continously because of the short life of the bulb. My 1948 C170 has a retractable in the left wing holding a very rare and expensive light bulb. I would appreciate any members assistance in directing me to a source for acquiring this bulb,should the need arise in the future.
Bob

[Kyle Wolfe]

Bill, changing the bulb is no big deal. It's just that I never made the feeler gauges as mentioned in the "Timeless Classic" book showing how to allign the landing lights. And being of Scandinavian background I can't count beyond 10 - so I never count the number of turns that the screws take to back them out. Besides, I've got the allignment messed up now anyway. So it's one of those deals where I go fly at night, realize the lights need to be moved either up-down-left-right, but forget about it till the next flight after dark.

I love working and playing on our airplane as much as the next guy - but this is just one of those little aggravations.

And then I hop in my wife's car with the blazing million power blue headlights and wish I had MORE POWER! Guess I'll just have to start carrying one of those portable million candle power lights that we use to spot light deer (for observation purposes only, of course!)