GPU usage

aerolithium · April 12

What methods are people using , GPU, to start their engines ? I dont see any talk about that here.

W E Hawn · April 30

HEMS for 15 years. Most often, the aircraft sat on the pad with the GPU connected, starts would be accomplished uising the GPU reserving the battery for the start with the patient loaded.

The only issue with this procedure was the occasional weak battery being discovered at the worst possible time, with a marginal or failed start with the helo remote from maintenance and patient loaded.

aerolithium · April 30

Well, that issue can be resolved with a portable starting GPU.

Aerolithium has them, What's your opinion of those ?

W E Hawn · May 1

An excerpt from my post outlines the major issue I found with battery/gpu starts-

"The only issue with this procedure was the occasional weak battery being discovered at the worst possible time, with a marginal or failed start with the helo remote from maintenance and patient loaded."

All starts at the base were done on the GPU for a while. The idea was that the on-board battery would not have been depleted and would be 'freshened' on the leg to the pickup point. That didn't always work as intended, the battery would, indeed, be brought to it's highest energy state charging enroute (unless a very short distance).

Problem not addressed was that on-board batteries wear out, they're used throughout the flight and an old battery's "highest energy state" might be a near normal high amperage over a very brief time, so the battery would deliver less and less current as the start progressed. An old battery in this situation might deliver all the single button-push starts you need with no problem... until you have an abnormal situation, say one must abort, shut down during the start without recharging. GPU starts obscure the issue until one is stuck somewhere with an aborted start and dead battery.