Contaminated Runway is defined as 25% of the runway surface area contaminated by which conditions?

• A. 25% area with standing water 1/4"
• B. 25% area with standing water 1/8"
• C. 25% area with any of the listed conditions
• D. 10% area with ice

Answer: (C)

Contaminated runway is defined by how much of the surface is affected, not by a single patch. If 25% of the runway surface is covered by any of the specified contaminants—standing water (at applicable depths), ice, snow, or related conditions—the runway is considered contaminated. That makes the broad option the best because it covers all the listed scenarios rather than tying contamination to one specific condition or to a smaller area.

The other options are narrower: they tie the 25% threshold to a particular condition or use a different area percentage, which doesn’t align with the general rule that 25% coverage by any listed contaminant qualifies as contaminated.