Why do people say "Contact" prior to starting an aircraft? Is this solely for propeller aircraft?

Question

I really just want to know why the word contact was chosen. What does this represent?

Answer 1

This is a throwback to when planes had to be proped by hand. When starting a plane with the prop, it can be very dangerous if not done correctly. Yelling "contact" was to let the guy spinning the prop know that the mags were hot. Today, you will hear most pilots yell "clear" before starting their aircraft. This lets everyone know that the prop is going to spin and the engine is going to start, so stay clear.

Answer 2

Borrowing Dirk D's answer, it's for most propeller aircraft.

On some aircraft, it falls to the lineman to read the pilot's signal, raised index finger swirled like you're stirring an inverted drink, and the other finger indicating which engine, tell you which engine's about to start.

"Contact" is actually likely an abbreviation as magnetos operate by having a contact closed ground and kill them. If I had to guess, I'd say the original meaning is "contact off," or "open," and despite how it's been done, is not something I want to hear when I'm in intimate proximity of a propeller.

You wouldn't believe the cash you have to shell out to get me to handprop an airplane these days.

Most turboprop operators request a GPU for engine start, (they can start off the aircrafts battery but prefer not to,) and the noise from that alone is sufficient to let people know not to get near the props. And you can't hear yourself think over the thing, so yelling out the window is pretty much out of the question.

Answer 3

Back in the early days (think WWI), a ground crewman would turn the prop, therefore turning the engine, a few times to prime the cylinders, with the magneto off.
Then, the pilot would turn on the magneto (CONTACT is on), so when the ground man would spin the prop, the engine would fire (hopefully).
To keep in communication with each other, the ground man would call out for the "contact off", answered the same by the pilot, so the pilot knew the ground man needed the magneto off, and the ground man knew (hoped!) the pilot had the magneto off.
When ready to start, the ground man would call for the magneto to be turned on, "Contact on". The pilot would respond likewise, or shorten it to just "Contact".

Answer 4

The pilot should always call “CLEAR” out of the side
window and wait for a response from persons who may
be nearby before activating the starter.

Even though most airplanes are equipped with electric
starters, a pilot must be familiar with the procedures
and dangers involved in starting an engine by
turning the propeller by hand (hand propping).
The procedure and commands for hand propping are:
Person out front says, “GAS ON, SWITCH OFF,
THROTTLE CLOSED, BRAKES SET.”

Pilot seat occupant, after making sure the fuel is
ON, mixture is RICH, ignition/magneto switch is
OFF, throttle is CLOSED, and brakes SET, says,
“GAS ON, SWITCH OFF, THROTTLE
CLOSED, BRAKES SET.”

Person out front, after pulling the propeller
through to prime the engine says, “BRAKES
AND CONTACT.”

Pilot seat occupant checks the brakes SET and
turns the ignition switch ON, then says,
“BRAKES AND CONTACT.”


The words CONTACT (mags ON) and SWITCH OFF
(mags OFF) are used because they are significantly
different from each other. Under noisy conditions or
high winds, the words CONTACT and SWITCH OFF
are less likely to be misunderstood than SWITCH ON
and SWITCH OFF.

Never allow a person unfamiliar with the controls to
occupy the pilot’s seat when hand propping. The
procedure should never be attempted alone.

Answer 5

Actually more common these days you will hear "Clear Prop" from the pilot.

"Contact" is a throwback to earlier days when electronic starters did not exist and was to signal the guy on the ground who was serving as the prop-spinner from the pilot that the magnetos (a combination generator-distributor-coil device) are now switched on and ready for the prop to get that one last turn to fire up the engine.

I've "propped" a few planes. It's quite dangerous.

Answer 6

It dates from the early days of aviation. The man pulling the prop through would pull it down to clear fuel and/or oil from the cylinders, or to prime the cylinders, and would tell the pilot prior to pulling, "Switch off", meaning make sure the magnetos are off. When ready to start, he would tell the pilot, "Contact", meaning turn the magnetos on.

Answer 7

The idea is to warn everyone that the engine is starting and that there willl be a danger zone around the propeller

Answer 8

It means the contact that allows the engine to start has been activated. (the switch).

Answer 9

contact is to say i have the ignition on and the engine is ready to fire, so ones the person on the prop pull it down the engine will fire.

Answer 10

Dirk D got it right