Can a Portable GPS Unit (PGU) be used for IFR navigation?

A Portable GPS Unit (PGU) can indeed be used for IFR (Instrument Flight Rules) navigation, but it comes with specific conditions and limitations. The correct understanding is that while a PGU can aid a pilot in navigation, it cannot be solely relied upon for IFR procedures without meeting certain criteria.

In IFR operations, the aircraft must be equipped with certified and specifically designed avionics that meet regulatory requirements for navigational accuracy and reliability. A PGU, while useful, does not typically meet these standards, which is why the correct answer highlights that it can be used with limitations, acknowledging that appropriate equipment must be on board and used according to regulations.

The incorrect choice reflects a misunderstanding of how supplemental navigation aids can work in conjunction with primary systems, emphasizing the importance of adhering to aviation regulations that dictate the use of navigational equipment based on the specific flight conditions and environments.