The proper time window for testing an ELT is:

• A. The first 5 minutes after the hour
• B. The last 5 minutes after the hour
• C. Any 5-minute interval during the hour
• D. Not during the hour at all

Answer: (A)

Testing an ELT is kept to a short, predictable window to minimize interference with other transmissions. The proper practice is to perform the test during the first five minutes of each hour and keep the test to a brief duration (about five seconds). This timing helps ensure the test is unlikely to be mistaken for an actual distress signal and reduces the chance of cluttering the airwaves with unnecessary transmissions.

Testing later in the hour, or choosing any five-minute interval other than the first five minutes, could collide with other checks or ongoing operations and create unnecessary interference. Not testing at all during the hour would also violate regulatory requirements that mandate periodic testing.