What holds an aircraft until ready to launch on an aircraft carrier?

Darrin Hixenbaugh: Surrounding the nose gear strut of a carrier-based aircraft are the components that both prevent and, then, facilitate catapult launches.Forward of the strut is a "launch bar" that hooks into the catapult's "shuttle," the part of the catapult that drags and accelerates the plane up the deck.Behind the strut is a "holdback fitting" that attaches to the holdback bar, attached to the carrier deck, that holds the aircraft stationary until the moment of launch.When the aircraft taxis up to the cat, the launch bar is seated in the shuttle, and the carrier's holdback bar is attached to the aircraft's holdback fitting. The aircraft goes to full power (called "taking tension"), and while the pilot does a final wipeout to check flight controls, the catapult is energized. When the pilot is ready to launch, he salutes (or at night, turns on his lights), and the catapult crew presses the launch button. The holdback bar drops free of the aircraft and stays in plac! e, and the aircraft is dragged up the deck by its launch bar, by the shuttle. It took about 2.5 seconds to take a 65,000 lb. Tomcat from 0 to 150 knots indicated airspeed.The aircraft is, indeed, at full power. If either the catapult or the motors fail during takeoff, there is a good chance the aircraft will not achieve flyaway endspeed (at least about 100 knots). If that happens, the only option is to eject.The brakes are not applied in the catapult process. On land, however, the pilot will often apply brakes when cleared for takeoff, and go to a medium power setting to do an engine check and wipeout, similar to the one on the carrier, but not at full power. At full military power or any afterburning setting, our motors would overpower the brakes and start us skidding. After the wipeout, the pilots will release brakes and start rolling for takeoff....Show more

Rocio Karvis: They are not at full throtle but itsThe brakes that keeps them from Rolling.

Adria! n Sherlin: NO brakes used on launch...they'd blow about half-w! ay down the track. Any "smoke" is simply steam from the shuttle.Absolutely at full throttle for launch...no pussy-footin' around when it comes to launching off the boat! In the old Tomcat days ("A" model), it required an afterburner takeoff... one of the world's most fun-to-watch launches at night: forty foot twin roman candles coming out the back!Source: VF-101 Flight Surgeon/NATOPS qual'd, 1997-2001....Show more

Trena Berum: The steam catapult holds the aircraft in place and then pulls the aircraft down the deck on launch.

Garry Ohmen: What Scott said, the steam cat only works one way, forward and won't hold anything back. Also, if you watch some of the launch videos, you'll aircraft going with smoke coming from the tires -- that would be with the brakes locked.In other words, holdback tool required.

Florencio Dingle: Most of you are wrong!! What holds back the aircraft is a device known as a hold back pennant. It goes between the hold back bar a! nd a fitting on the aircraft. It is made of solid steel. It is precisely engineered to break at a certain tensile stress. The engine revs to 100% military power. After the engine gets a thumbs up the catapult is pressurized. When all is go, the catapult pressure is increased until the hold back pennant breaks. It is a controlled, high stress break. That is the only way you can get that amount of acceleration to achieve lift in so short a distance....Show more