Optical Radiation Transmittance of Aircraft Windscreens and Pilot Vision

Optical radiation can have acute and chronic effects on the tissues of the eye, especially if exposure levels exceed normal repair capabilities. In support of a Department of Homeland Security project, the transmittance properties of aircraft windscreens were measured at the Federal Aviation Administration’s (FAA´s) Civil Aerospace Medical Institute (CAMI) for both visible and invisible optical radiation. This paper focuses on windscreen transmittance in the ultraviolet (UV) (< 380 nm) and visible (380-780 nm) portions of the optical spectrum. Transmission measurements were performed on eight aircraft windscreens. Three windscreens were from large commercial jets (MD 88, Airbus A320, and Boeing 727/737); two from commercial, propeller-driven passenger planes (Fokker 27 and the ATR 42); one from a small private jet (Raytheon Aircraft Corporation Hawker Horizon); and two from small general aviation (GA), single-engine, propeller-driven planes (Beech Bonanza and Cessna 182). The two GA aircraft windscreens were plastic (polycarbonate); the others were multilayer (laminated) composite glass. UV transmittance for both glass and plastic windscreens was less than 1% for UV-B (280-320 nm) radiation. In the UV-A portion (320-380 nm) of the spectrum, transmittance differences increased from 0.41% to 53.5%, with plastic attenuating more UV radiation than glass. For visible light, average transmittance from 400-600 nm (violet to orange) was similar (82.8% ± 4.6%) for both windscreen materials, while from 625 to 775 nm (orange to red), the difference in average transmittance increased from 9.1% to 40.0%, respectively, with plastic transmitting longer wavelengths more efficiently. Both types of windscreens blocked most of the more harmful UV-B radiation; however, glass laminate windscreens allowed higher levels of potentially damaging UV-A radiation to be transmitted than did plastic. Professional pilots who routinely fly at higher altitude for longer periods of time than private pilots should take special precautions to protect their eyes from UV exposure.

Language

  • English

Media Info

  • Media Type: Print
  • Edition: Final Report
  • Features: Figures; Photos; References;
  • Pagination: 17p

Subject/Index Terms

Filing Info

  • Accession Number: 01056030
  • Record Type: Publication
  • Report/Paper Numbers: DOT/FAA/ASM-07/20
  • Files: TRIS, USDOT
  • Created Date: Aug 27 2007 11:30AM