‘Usually, the planned or estimated gross weight before taxiing will be written in chalk on the aircraft’s nose-gear door,’ John Chesire, former Naval Aviator
An aircraft catapult is a device used to allow aircraft to take off from a very limited amount of space, such as the deck of a vessel, but can also be installed on land-based runways in rare cases. It is now most commonly used on aircraft carriers, as a form of assisted take-off.
In the form used on aircraft carriers the catapult consists of a track, or slot, built into the flight deck, below which is a large piston or shuttle that is attached through the track to the nose gear of the aircraft, or in some cases a wire rope, called a catapult bridle, is attached to the aircraft and the catapult shuttle.
Other forms have been used historically, such as mounting a launching cart holding a seaplane on a long girder-built structure mounted on the deck of a warship or merchant vessel, but most catapults share a similar sliding track concept.
What is the green shirt (actually green shirts are responsible for Catapult and Arresting Gear aboard an aircraft carrier) in the photo of this post showing to the F/A-18 Super Hornet pilot before catapult launch?
‘He is showing to the pilot what he believes is the gross weight of the aircraft on the catapult. This weight is extremely important. It needs to be known for proper setting of the catapult,’ says John Chesire, former Naval Aviator, on Quora.
‘Usually, the planned or estimated gross weight before taxiing will be written in chalk on the aircraft’s nose-gear door. The guy in green will show this weight to the pilot for confirmation. If the pilot agrees with that weight displayed, he will give a “thumbs up”. If the pilot knows that weight shown to him is incorrect, he will signal with his hands to raise or lower the displayed weight until it matches the correct gross weight. He then will give a thumbs up; the catapult crew will set in the proper adjustments for that weight, and the aircraft will soon be shot off the deck.’
Chesire concludes;
‘This occurs on every flight and launch.’
Photo by U.S. Navy