PLT154: Static Equilibrium And Weigh Off
What code PLT154 covers, why the FAA tests it, and how to study Static Equilibrium And Weigh Off before your checkride.
Recall airship - ground weight-off / static / trim condition
What this means for your checkride
Before release, a lighter than air craft is brought to a static, neutrally buoyant condition so it is neither heavy nor light, a process the gas balloon community calls the weigh off. Crew or ballast are adjusted until the craft sits in equilibrium, then a small amount of ballast is removed to set the desired positive buoyancy and ascent rate. Establishing this static condition first gives the pilot a known baseline from which to control the flight.
Determining the static equilibrium condition on the ground is how the pilot confirms the craft is trimmed for a controlled, predictable departure.
Neutral buoyancy is not the same as being ready to climb. Extra ballast must be removed, or heat added, to move from equilibrium into a controlled ascent.
Where to study it
A code on your test report is an area of deficiency. An authorized instructor must review it with you and endorse that review before you take the practical test, and the examiner may revisit it during the oral. Study it until you can explain it out loud, not just recognize the answer.