How many emergency locator transmitters (ELTs) should be checked during PDIs?

The correct answer is that during Pre-Delivery Inspections (PDIs), one emergency locator transmitter (ELT) should be checked. This practice is aligned with established safety protocols and regulatory standards, which typically require a systematic inspection of safety equipment on the aircraft.

When performing a PDI, the focus is on ensuring the functionality and proper operation of essential safety devices, including the ELT. The aircraft is generally equipped with one primary ELT, which is designed to automatically activate in the event of a crash to transmit distress signals to search and rescue services. Ensuring that this single unit is checked confirms that it is in working order and ready to function when needed.

While it's prudent to acknowledge that additional measures or backups may exist in some aircraft types, the core requirement during the PDI centers on the primary unit. Checking multiple ELTs, although beneficial in some contexts, exceeds the standard expectation for this specific inspection type, which is why the focus is primarily on the one dedicated unit. This practice reinforces the importance of maintaining reliable emergency equipment as part of overall flight safety strategies.