Independent Testing By M7 Labs Shows 100 Percent Removal Of UVA Light

Because of the significant increase in UVA radiation at higher altitudes, many pilots recognize the danger of sunburns, skin cancer and the degeneration of their vision.

That led M7 Labs, the technical arm of the speciality optics manufacturer Method Seven, to measure the spectrum of light and the percentage of UVA that passes through the windscreen.

The tests found that the canopies of Stemme aircraft S10 and S12 received outstanding results. They do remove 100 % of the UVA light. Before M7 has characterized the windscreens on 73 different aircraft, a study on this subject sponsored by the Federal Aviation Administration (FAA), and conducted by the Civil Aerospace Medical Institute (CAMI) was already published in 2007.

Although the in-situ test technique of M7 might be less precise than the CAMI, it allows to measure a larger number of samples than CAMI. M7 Labs uses a tool called a spectrometer to evaluate how lenses filter light across the ultraviolet, visible, and beginning near infrared portion of the light spectrum. They calculated the ratio of total UVA energy passing through the windscreen divided by the total UVA energy of the sunlight shining towards the windscreen. These measurements provide a calculated value for the percentage of UVA that passes through the windscreen.

Some windscreens do an excellent job of filtering out UVA light - but not all. UVA is a pronounced problem for pilots because the intensity of UVA radiation increases approximately 15% for every 3,000 feet of altitude above sea level. The data also bases on the service ceiling for each aircraft because altitude plays a key role in how much UVA a pilot might be exposed to.

Out of the 73 aircraft tested, 45 windscreens removed 100% of the UVA light, including the Stemme models. Seven aircrafts allowed 30% or more UVA light to enter through the windscreen. Most cockpit windscreens do a good to reasonable job of filtering out UVA light. “We are pleased that the UVA transmittance of the S12 canopy was rated with 0 %. This confirms the decision, we made throughout the development, for the manufacturer, who stated a value of less than 1% in the technical data sheet," said Jürgen Schlümer, Head of Design Organization at Stemme AG.

(Images provided with Stemme AG news release)

FMI: http://stemme.de