What’s the Difference Between a Halogen and a LED PAPI?

What’s the Difference Between a Halogen and a LED PAPI?

What’s the Difference Between a Halogen and a LED PAPI?

By:Avlite Systems | May 21, 2021

Historically, PAPIs have used halogen lights. But in the last decade, LED PAPI lights have entered the market. These lights provide numerous advantages over halogen models. We explain the key differences below.

Comparing Halogen and LED lighting

To start, it helps to clarify the two different light types:

  • LED stands for light-emitting diodes. This type of light bulb uses a diode rather than a heated filament to produce light.
  • Halogens are a type of incandescent light bulb which uses halogen gas to deliver light. Compared to traditional and LED bulbs, halogen lights are extremely hot.

The key difference between an LED and a halogen light is efficiency. Light dissipates within a halogen bulb, but does not with an LED. This allows an LED to be significantly brighter, and also better at concentrating light in one direction.

This efficiency makes LED lights cheaper to run and burn at lower temperatures. The cost of running a light bulb is based on how many watts it takes to run it continuously for one hour. LEDs can use anywhere from 7-20 watts per hour, whereas halogens use anywhere from 35 to 500 watts an hour to emit the same amount of light.

By using less power, LED lights reduce the demand on the power system. This helps cut down on greenhouse emissions. LEDs also do not contain any toxic substances like mercury. Reducing emissions is an ongoing strategic initiative for many airports around the world.

There is another added benefit to this efficiency: product lifespan. An LED’s average life span is also about 41 times more than a halogen bulb. Specifically, an LED has about 50,000 hours of life compared to the 1,200 of halogen lights. This means you don’t need to replace them for over ten years.

Halogen PAPIs: Cheaper upfront, costly long-term

So, with all these benefits, why would anyone buy a halogen PAPI? The reason is halogen PAPIs come with a smaller upfront price tag.

However, for the cost-conscious, LED PAPIs make a lot more sense. The LED models require significantly less upkeep. A halogen PAPI requires its light bulbs changed every three to six months, as well as constant checks on backup systems. This takes time and money. Meanwhile, the only maintenance a LED PAPI requires is calibration and cleaning.

Halogen PAPIs also need inbuilt redundancy. If a globe goes out, it must rely on its backup light for this critical approach information source. However, a LED PAPI does not have this issue – it is designed to last its entire lifetime. In the rare situation an LED light goes out, the software compensates, and the information displayed to the pilot is unchanged.

The final consideration is enhanced features. LED PAPIs provide sharper red to white transition. With halogen PAPIs, there is a light bleed from its filters, meaning light information can be distorted. These lights transmit critical approach slope information to the pilot, so accuracy is key. Using high-fidelity lighting is simply a matter of safety, and can’t be taken for granted in the value equation.

Interested in an LED PAPI?

Stay tuned for our on-demand webinar released next week discussing ‘How an LED PAPI is Better for Lifetime Ownership.’


Jason Larrere
Regional Sales Manager – Americas

Wade Evans
Product, Project and Solution Manager – Aviation and Digital

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