Final answer:
Exemption 17347 pertains to alternate airport filing requirements under specific circumstances that allow pilots to deviate from the standard FARs. A second alternate must be filed if the weather conditions at both the destination and the first alternate airports are forecast to be below certain minima. It is applicable to pilots who can meet the exemption's criteria.
Step-by-step explanation:
The question refers to a specific situation in aviation under the Federal Aviation Regulations (FARs). Specifically, Exemption 17347 pertains to the filing of alternate airports in a flight plan. Under the standard FARs, pilots are typically required to designate an alternate airport when certain conditions are forecasted at the destination airport, such as insufficient weather minimums for landing. Exemption 17347 may provide relief from this requirement under certain circumstances, allowing pilots to file for an exemption based on the specifics of their flight operation or equipment.
If Exemption 17347 is applied, a second alternate is required when the weather conditions at both the destination and the first alternate airports are forecast to be below certain minima at the estimated time of arrival. These minima are usually determined by the approach procedures available and aircraft capabilities. The decision to file under this exemption requires careful consideration of weather forecasts and aircraft equipment, ensuring that there is a backup plan in case the primary and first alternate airports are not available.