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rate of descent, and if you are push- ing against them, the door simply won’t drop down. The act can leave you standing there holding the door up and looking like an idiot in front of the passengers. So, the drill is to pull the handle, give the door a good yank, then get out of the way while it descends all by itself.
The door stops its automatic de- scent when it is about 6 inches from the ground and hangs there while a rubber-tipped foot drops down to the ground to support the door while passengers ascend the stairs. The problem is if the airplane is light, say with half tanks or less, it sits higher on the landing gear and the rubber-tipped foot does not touch the ground. Consequently, if a heavyset passenger puts all their weight on the first step, the door can overextend the hinge attached to the fuselage, bending the metal and effectively grounding the airplane on the spot.
To prevent this disaster caused by “pilot oversight,” a 4-by-4-inch block of scrap wood is kept near the door entry. It is the pilots’ job to make sure that piece of wood is placed under the rubber stop before anyone is allowed to board. Upon departure, the pilot (in addition to dealing with IFR clearances, fuel and baggage loading) must also remember to re- trieve that piece of scrap wood be- fore the door is closed. If forgotten, it can cause all kinds of turmoil at the next stop. It is indeed peculiar that a piece of scrap wood is an operational necessity in an airplane costing $14 million, but it is a difference that must be learned and demonstrated before a new pilot checkout.
Once you master the door, it is time to move on to other things. On nearly all small jets, the batteries are typically disconnected from the aircraft before it is parked because there are hot battery bus items that can discharge them overnight. But on the G150, they are in the back of the airplane and inaccessible to the pilot during pref light. So, after opening the door, the pilot’s next job is to turn on the master switch and see how much power remains
in the batteries. It must be 24 volts or better, but don’t sit and stare at the display too long after turning the master on. The batteries will deplete and you won’t be able to start the APU, effectively grounding the airplane unless ground power is available.
Starting the APU has its own ritual. First, you must check the unit’s fire suppression system by pressing the half-inch square arm or test switch on the center of the instrument panel, all the while tak- ing great care to keep your other finger off the discharge switch of the same size immediately next to it. If you accidentally push that switch, the bottle will discharge and ground the airplane until the mess can be cleaned up and the fire bottle re-charged. Then comes a test for fuel availability to the APU, which comes from the right engine sup- ply. If this is good to go, the APU itself can finally be started with the push of a button. The little jet engine starts almost right away. With a lot of small jet APUs, there is a required delay of a couple of minutes to allow the engine to warm up before the generator and ECS (environment control system) is switched on. But on the G150, while there is a two- minute delay only on the ECS, the generator can come on right away. All kinds of funny little differences to remember that have very little to do with actually f lying the aircraft.
Now with the little jet engine roaring away in the back and the ECS warming the cabin, it is time to actually do the walk around part of the preflight. This involves the usual steps like making sure the tires are inflated, but there are also a couple of peculiar exceptions that must be dealt with – one of which is the nose wheel steering system. The nose wheel has a pin that must be pulled when the airplane is parked, completely disconnecting the wheel from its control linkage. It must then be re-connected before any attempt (other than a very embarrassing one) is made to taxi the aircraft. Re-in- serting the pin, however, turns out to be best completed by both pilots
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Jet Journal December 2019 / TWIN & TURBINE • 27