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Air. (At least not when I worked at the factory, 1972-1977. I wonder if the Textron Production Test Flight department still lets them spin?)
So from this experience I am not worried about restraining the props during a fuel stop or passenger drop- off or pickup. Even if the airplane will be sitting for hours waiting for the passengers to return, I will still not install them if the wind is light and forecasted to remain that way. But overnight stops? For these I will always install the restraints along with the other “loose equipment” items, like pitot tube covers and intake plugs. In fact, I will do this even if I have arranged for hangaring the airplane overnight at the FBO, since I don’t know what the wind condition will be when they pull the airplane out onto the ramp an hour or so before the scheduled departure the next day.
I have observed some operators who do not always use the Beech- provided restraints but instead have taken a simple bungee cord of the right length so that it can be looped to tie one blade to one exhaust stack. This eliminates the hot stack worry since the tight-fitting exhaust cover does not need to be installed. The simple bungee is used when it’s windy even during a relatively quick turn and the “proper” restraint only is used for the overnight situations. By the time the passengers and baggage are off-loaded, the fueling is done, the potty stop has been made and the other covers and plugs installed, the exhaust stacks are cool enough that affixing the restraints to them is not problematic.
However, a word of caution: If you are going to use the simple bungee cord, I strongly suggest having a big, red “Remove Before Flight” tag that can be readily seen from the cockpit attached to it. It’s embarrassing to get all situated ready to start and then realize the bungee was never removed. And that leads to this humorous war story.
One day back in the 1960s, a King Air A90 had made a trip from its Northeast home base airport to LaGuardia Airport (KLGA) in New York. The chairman of the board (COB) and his aides were the passengers and he, the COB, had a very important dinner meeting back home that evening. It was a cold and windy day so the airplane sat at KLGA with the standard prop restraints in place.
As the day wore on, the nervous- nelly chief pilot, who was PIC that day, got more and more worried that the boss would not return in time to make his dinner engagement. He briefed the co-pilot, “Now when the boss arrives, you load the passengers and get the door and I will go straight to the cockpit to get the clearance and start the engines.”
“Is that him?” “Is that him?” was the PIC’s query as each limousine arrived. Finally, there he was! Like a bullet, our intrepid hero ran to the cockpit to get ready. The copilot, as directed, saw that everyone was safely aboard, briefcases stowed, briefing given. Before he pulled the airstair door up, he heard the sound of the right engine being started yet he hadn’t yet pulled the restraints! He quickly, temporarily
(he thought), closed the door and raced up the aisle. “Mike! Mike! Wait, I haven’t untied the props!” He could also see the linemen waving at the cockpit and pointing to the still-tied down right prop that was not yet rotating but pulling strongly against its restraint. About that time, as the engine reached high idle, the exhaust burned through the stack covers and the elastic cord broke, flinging off the sleeve and freeing the propeller. “Hell, that worked. We need to get moving. Sit down and buckle up.” And with that, the PIC fired up the left engine, burned off its restraint and proceeded with the flight.
(This story was relayed to me by the copilot. Names have been changed to protect the not-so- innocent. I never found out if the boss made his appointment!)
So I learned from that incident that (1) You need some visual reminder that the restraints are installed, (2) The engine starts satisfactorily with the fabric exhaust covers on, not reaching excessive ITT and (3) Never be in such a hurry!
Regarding the blade up versus blade down argument. In the days of nothing but three-blade propellers, there was – and still is for those with three-blades – a “correct” answer: down. This is true for two reasons. First, the shape of the exhaust covers and the angle at which the elastic straps connect to them permit the stack cover to fit perfectly when the strap comes upward to the cover. If the strap angles downward, the exhaust cover can be forced to fit but it is obviously not designed with that position in mind. Second, why was it designed this way? So that rain could drain out of the spinner through the hole for the down blade. There were incidences reported of noticeable propeller vibration and it was traced to water that had collected in the spinner, turned into ice as the temperature dropped and left that ice slug inside the spinner, upsetting the balance.
The main reason that a lot of pilots prefer the blade up orientation is to make the restraint more obvious from the cockpit. There’s less chance of making the “Start with ’em on”
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24 • KING AIR MAGAZINE
SEPTEMBER 2024