PreciseFlight PulseLight: Be Seen, Save Bulbs

A pulsing landing light is definitely an eye catcher for collision avoidance. A side benefit is that pulsed bulbs seem to last longer.

For owners who worry about mid-air collisions, its no comfort to be told that the statistical risk of a mid-air is low. Its barely out of the noise level as a cause of accidents. Nonetheless, many who worry about mid-airs forget one simple thing that might improve the odds of being seen and avoided: turning on landing and taxi lights.

From certain angles and in the right lighting conditions, illuminated landing lights dramatically improve conspicuity. Its widely accepted that pulsing lights of some kind-either landing lights or strobes-improve the chances of being seen, especially in low light or low contrast conditions. And the more lights you can pulse, the better.

Thats the idea behind PreciseFlights Pulselite system, a device that pulses one or more landing lights, either together or in alternating sequence. The system has been on the market for years, so we decided to take a fresh look at how it works and to answer a persistent question: Do Pulselites really make landing light bulbs last longer? (Short answer: Yes, they certainly do.)

Weve had Pulselites in three of our aircraft and have considered them to be relatively inexpensive safety gear. PreciseFlight loaned us the latest iteration of the Pulselite for bench evaluation. Although there’s competition in the field from AvTeks Pulsar system, the company refused to loan or sell us their product for evaluation. AvTek owner Mike Peters told us that if we reviewed the Pulsar favorably, hed “have a problem” because he couldnt deliver many units. Similarly, he said he would also have a problem if we found fault with it. we’ll try to obtain a Pulsar in the future to shine some light into this dark corner.

Two Models
Meanwhile, PreciseFlight offers two models for light aircraft, the 1210, which channels two lamps at 125 watts each, or one 250-watt lamp ($295) and the Starlight 3060, which channels two 500-watt lamps for $1395. The Startlight has another neat trick: It interfaces with TCAS and automatically pulses the landing lights when a traffic advisory is active. PreciseFlight also sells commercial duty pulsers to the airline and bizjet trade.

Since the 1210 is nothing more than a controllable switching circuit, there’s really not much to it. The circuitry is contained in a small chassis thats mounted to a substantial heat sink that doubles as a mounting plate. The device is intended for installation inside the cabin, not where it will be exposed to weather.

The STC package is complete with all of the paperwork and nicely detailed drawings for most of the airframes the system is approved for. (Thats just about everything, according to the fat pile of paper that comes with each Pulselite.)

Instructions are complete and lucid and installation requires between four and six hours, according to PreciseFlight. The device can be wired to flash two lamps simultaneously or alternately and the pulse rate can be selected at 45 or 90 pulses. It requires the installation of a single switch that turns pulsing on and off. The pulse rate can be hardwired or selectable, with an additional switch.When the landing light is turned on, it routes power directly to the bulb.

Testing It
We know the pulsing action works and that it improves conspicuity. For example of that, check out the video clips on PreciseFlights Web site ( We were curious to see if the Pulselite could, as claimed, extend the life of the typical landing light.

Our bulb durability tests published in the July 2006 issue all but established that the GE4509 is the poster child for burned-out lamps, so we wired the Pulselite to a fresh 4509, fired it up and started the timer. (As noted in our landing light trials, the 4509 is doing we’ll to last 10 hours.)

One thing was immediately obvious and hardly surprising. When pulsed, a landing light runs cooler than it does when illuminated continuously. During our bulb tests, we found that 4509 lamps reached about 113 degrees F when measured between the terminals and the back of the reflector. When pulsed, the same bulbs heated to about 90 degrees F.

Further, in addition to less heat, there’s also less voltage. In a normal aircraft bus, the landing light runs at about 13.5 to 13.8 volts, higher than the bulbs nominal 13-volt rating. When pulsing, we noticed voltage spikes no higher than 12 volts, and usually between the 10 and 11 volts. (The pulse is so short that our meter had trouble recording it.)

Does all of this add up to longer bulb life? PreciseFlight says so and our tests confirm that. The same 4509 that failed in an average of under 10 hours when burned continuously, lasted at least 130 hours when pulsed. (We stopped the test at that point.) We cant confirm PreciseFlights claim that bulbs last 20 times longer but we don’t dispute it, either. Bulbs definitely do last a lot longer.

We still think investing in HID lighting is the overall best way to improve landing and taxi light performance. But if thats not in your budget and you favor illuminating landing lights as a means of avoiding collisions, by all means consider a Pulselite.

For about $400 installed, it will clearly improve the life of landing light bulbs, perhaps manyfold. And a pulsing lamp is simply more conspicuous than one thats steadily illuminated.

Contact – PreciseFlight, 800-547-2558,