What type of aircraft is required for Basic Essential Air Service (EAS)?

The correct choice for Basic Essential Air Service (EAS) is the twin-engine, 15-passenger aircraft. This requirement arises from the specific regulations governing EAS, which is designed to ensure that communities with limited air service have access to reliable and safe transportation options.

Twin-engine aircraft are preferred for EAS to ensure increased safety, reliability, and ability to operate under various conditions, especially in less developed regions where airstrips may not be as robust. The 15-passenger capacity is aligned with the goal of providing adequate service to these communities, enabling airlines to efficiently cater to demand while ensuring that the service remains economically viable.

In contrast, the other options either do not meet the minimum passenger capacity or introduce limitations that wouldn't effectively serve the intended purpose of EAS. For example, single-engine aircraft may not offer the same level of safety or operational capability, especially in less-than-ideal weather conditions, while helicopters, despite their versatility, generally do not align with the operational and capacity standards set for EAS.