Answers for Pilots

Passing the color vision test

A pilot attempting to land in Florida had a rude awakening as he approached touchdown — the "runway" that he was heading for turned out to be a canal.

How could that happen?

The pilot had color-deficient vision; he could not differentiate between blues and browns.

Color deficiency affects nearly 10 percent of the male population (and a negligible percentage of females). Color deficiency is different from the more commonly known term color blind. Someone who is color deficient cannot see the intensities in colors, hence a shade of blue could appear more brown. A color-blind person cannot see any difference between certain colors.

Pilots affected by color deficiency may have color vision limitations placed on their certificates if they cannot pass a test administered by their aviation medical examiner. This would restrict the pilot from night flying and from any operation requiring color light signal controls. Ironically, a color-deficient pilot may have passed the color vision test consistently throughout his flying career until one day when he's tired, facing a new examiner, not feeling well, or any number of other life situations, and — boom — he has a color vision restriction. The varying methods of testing available allows situations in which the pilot had the deficiency yet had been able to pass the test previously.

Such is the case of Dale Weaver, AOPA 1224450, a 39-year-old, 300-hour pilot from Macon, Mississippi, who cannot differentiate between greens and browns. "I'm a farmer with my father-in-law. When the wheat begins to sprout, he can see the greening much earlier than I," said Weaver. His previous AME had issued Weaver's medical even though he had the deficiency because Weaver could differentiate between green and red. "I admit that I do have trouble with the VASI [visual approach slope indicator] lights from a long distance. But a little closer, and I'm fine," said Weaver. Then his AME retired and his new AME put the color vision restriction on his medical because he failed the same test.

What was the difference between the way the two AMEs administered the tests? It's a surprisingly common question and one that the medical specialists available on the AOPA Pilot Information Center can answer. The FAA's recently revised standards in FAR Part 67 state that a pilot must "have the ability to perceive those colors necessary for the safe performance of airman duties." There are seven different tests listed as acceptable in the FAA regulations. The tests, presented in books with pages, or plates, depict colored-dot patterns in which a letter or numeral is presented in a different shade (blues to greens, for example).

The AOPA medical certification team, headed by Gary Crump, advises callers that there are two options if the test offered by your AME indicates a color vision restriction.

"We advise [you] to see a local eye doctor," said Ruby Zecher, a member of AOPA's medical certification team. "They may offer the most commonly used acceptable substitutes to the Ishihara and pseudoisochromatic tests usually administered by AMEs."

For example, an AOPA member called from New York and Zecher recommended that he take his color vision test at another location, one that offered a specific test. She went so far as to suggest a doctor in Frederick, Maryland — the location of AOPA headquarters — where Dr. Phillip Evich offers that test. The New York pilot flew to Maryland and passed the test.

According to Evich, pilots can fail to differentiate colors on a greater number of plates on this test than on others and still pass. "If you are significantly color deficient, you will not pass any of the tests," said Evich. "But if your deficiency is marginal, you may pass this test."

The second option recommended by AOPA's medical specialists is to take a color signal light test. Ask a tower controller to flash the color light-gun signals in your direction. Have someone with you who has unrestricted vision to correctly identify the colors. If you believe that you would pass the test in this manner, request the test from the FAA's Aeromedical Certification Division in Oklahoma City. You may then take the test at an FAA Flight Standards District Office near you.

This information is outlined on topic sheets available by calling the AOPA Pilot Information Center (800/USA-AOPA) and AOPA Online ( www.aopa.org/members/files/medical/colorvis.html). The medical team has extensive aviation medical experience, and director Crump offers unique expertise — he has a color deficiency himself. Complete information is available in the Pilot's Guide to Medical Certification available by calling the center or on the AOPA Web site ( www.aopa.org/members/files/medical/medcert.html). Additionally, for $26 a year for private pilots, AOPA's Legal Services Plan provides representation in medical revocation and suspension cases.

And if you are thinking that color vision problems do not apply to you, remember this: Taking the anti-impotency drug Viagra may affect color vision. Don't go to see your AME for your medical until at least six hours after taking the drug.

As an AOPA member, you have access to the best source available anywhere for information and answers for pilots. The AOPA Pilot Information Center gives you direct access to specialists in every area of aviation. The AOPA Pilot Information Center, 800/USA-AOPA (800/872-2672), is available to members from 8:30 a.m. to 6 p.m. Eastern time, Monday through Friday.