Soft Cat Shot
Ttaskmaster asked about catapult launches earlier.
Here is a blog entry Lex wrote back in 2004. Not only does it describe a soft cat shot, it's also a good descriptor of the activity that goes on during a cat shot.
So here's Lex in his own words:
Soft Cat Shot
By lex, Wed – May 19, 2004
I’ve never had a cold catapult shot, thank God. Although I once had a nightmare about one, soon after I’d lost a colleague on a night cat shot.
But I did have a soft one, one clear day.
It was a hot summer’s day in the SoCal operating area. My jet was heavily loaded – a full bag of gas of course, with three external drop tanks fuel of fuel, rather than the two we customarily carried at sea. Also, a HARM missile (with its associated launcher rail) loaded asymmetrically on one of the outer pylons. I’d finished my pre-start and post-start checklist and gave the flight deck director, or yellowshirt, a thumbs up, indicating I was ready to taxi, ready for the launch.
He lowered his arms below his waist, where the signals to the flight deck crewmen go, and brushed his arms like he was rolling down his shirtsleeves. The breakdown signal. Blueshirts, chocks and chains guys, rushed below my aircraft to remove the tow bar and tie down chains that keep an airplane firmly in place until the hydraulic brakes are powered up by engine starts. In moments, they were clear, and passing the chains to my brown-shirted plane captain, I got the “off brakes” signal, timed carefully against the carrier’s roll, to taxi out of my parking spot and towards the bow catapult.
Once clear of parking, he raised his arms above his waist, where the signals to the pilot go, and waved them outward – spread wings. I cooled the AIM-9 sidewinder on my wingtip with the throw of a switch, and twisted the wingfold handle outboard. The Sidewinder having been checked for operation, the signal to fold wings followed, and I was brought forward once more.
Behind the jet blast deflector or JBD (the raised panels behind the aircraft in the photo below, designed to keep the engines from blowing flight deck personnel over the side, and pushing aircraft around when the jet on the cat goes to full power), I ran through as much of my take-off checklist as I could perform with the wings folded. Anti-skid: Off. Dispenser switch: Safe, Ejection seat: Armed, Flaps: Half, Nosewheel steering: Engaged, high gain. Trim: 17 degrees nose up, Wings: Hold on wings…
The catapults on US Navy aircraft carriers are variants of an originally British design (like most of our carrier systems, including yesterday’s Fresnel lens). Dry (superheated) steam from the main engines is stored in enormous accumulators below the flight deck, and carefully metered out based on the aircraft type, which drives the end speed requirement, to a suitable margin above stall speed, and aircraft gross weight – as an aircraft becomes heavier, the end speed requirement to maintain a given fly-away AOA is also higher.
The gigantic pistons which receive the metered steam are housed beneath the flight deck, with only the aircraft hook up point, or shuttle, poking above the flight deck level. Modern carrier jets have launch bars, which feed into the shuttle, and mechanically tensioned hold back devices to hold a screaming fighter at full power with the brakes off. Careful calculations are done throughout the carrier, taking into effect the catapult’s elongation (as they get hotter, they get longer), the outside air temperature (more airspeed is required on a hotter day, as the air density tends to be lower), the wind over the deck (more natural wind means lower generated airspeed requirements) as well as the previously mentioned type of aircraft and gross weight.
Much of this work, from the precise hook up of the aircraft to the shuttle, to the calculations of end speed requirements, to the monitoring of numerous and hideously complex catapult settings, safeties and steam gauges, is done by young Sailors scarcely 19 or 20 years old. I can think of nowhere else where someone so young so routinely has in his often exhausted hands the lives of so many expensively trained and educated people, not to mention tens of millions of dollars of equipment, on a daily basis. Catapult launches are occurring right now, as you read this, and someone barely out of high school, getting paid $18,000 a year (with sea pay) is giving the catapult officer a post-launch thumbs up, while waiting for the next aircraft. Unsung heroes.
The jet in front of me shoots off, and 80,000 tons of aircraft carrier shudders to the keel at the force of the catapult piston hitting the water brake to arrest its travel. The JBD is lowered slowly, and my canopy is blindingly enveloped by the (now wet) steam released from the catapult track. “Wings spread,” is signaled, and as I attempt with the director’s assistance to nudge my nosewheel precisely along the catapult track, I receive the signal to hold brakes, and lower the launch bar. A green shirt scurries beneath my nose, and guides the launch bar into the shuttle. I race through the remaining checklist items: Wings: spread and locked. Engine instruments: Hold on engine instruments… Re-check trim: Check. Re-check seat: Armed. Pray: Briefly.
The “take tension” and “release brakes” signals are given, simultaneously. The jet squats suddenly, jarringly as the engines fight with the holdback fitting, and the shuttle pulls forward, cocked and ready. Everything trembles and shudders in a delicate balance as my fighter shrieks to be released, to be set free, and unseen but massive accumulated forces sit implacably waiting for the push of a single button by a young man who scarcely needs to shave.
Two more checklist items to complete – Engine instruments: In the green, Flight controls: Free and correct. One last look at the engines with a gimlet eye, my right hand touches the ejection handle, just to make sure it’s still there. I glance at the emergency jettison button, just above the throttles, where I could reach it in a hurry. Everything is as it should be.
I look at the Shooter standing patiently beside my jet – it’s been at least five seconds since the “take tension, release brakes” signal has been given. I salute with my right hand, signaling willingness to launch, with my left hand bracing the throttles. He salutes back, and I place my right hand on the “towel rack” above my head, on the canopy bow, to hold my body firmly in the seat against the shot. The FA-18 flight computers will set the fly-away attitude on launch, and it’s best not to interfere. I’ll only grab the stick once she rotates.
The Shooter looks forward and aft, all clear. He gets a “thumbs up” from the deck edge operator. He looks forward again, kneels to get below my wing and touches the deck. When he raises his outstretched hand, the deck edge operator, hands held up and clear of all controls for all to see, will check his settings on more time, looking for any flaw in the settings, any warning lights. Making eye contact one more time with the Shooter to ensure that no one has given the “suspend” signal, he’ll punch a button with his right hand.
And the catapult will fire.
A good shot, it feels at first – good acceleration. But when I get to the end of the stroke, my jet does not spring into the air. She settles, and AOA warning tones go off in my headset. Something is very wrong.
Full afterburner, grab the stick, attempt to milk the nose: a little higher, a little higher, give me a fly-away attitude. The radar altimeter, set for 40 feet above the water, adds its voice to chorus in my headset as the waiting ocean swims up in my peripheral vision. Still settling. My left hand leaves the throttles, now parked in full blower, and my finger reaches into the ring that houses a single button, painted black and yellow, that once depressed will send three fully loaded fuel tanks and a multi-million dollar HARM missile tumbling into the sea. Earning me, no doubt, a new callsign .
“How’s it going, Slick?”
And that one factor, more than any other, gives me a moment’s pause. Because in those days, it was a truism of naval aviation that “it’s better to die than to look bad.”
A brown panic rises in the back of my helmet, chaos rising so quickly from order. Will I have to eject? Do I have time? Finally, she caught her breath, and started to climb out. I was so shaken that it took me some moments to raise the landing gear, and deselect the afterburner. My roommate, manning a spare on the port side of the bow, called up on the aux radio and asked, “Hey Lex. How did that, ah – how did that look from your cockpit?” Which is the kind of question one only asks of a someone who has somehow miraculously risen from the grave.
After a relatively routine flight and landing, I debriefed and made my way into the wardroom for chow, where the buzz of excited conversation centered around who had seen that Hornet settle off the cat on event five, what had happened, and who the hell was that guy?
“Oh, that guy? Just some idiot,” I answered.
Never did figure out what went wrong. Whether it was some flaw in the natural wind, or a miscalculation on the part of any number of people, who nearly always have to be perfectly right.
Didn’t really matter though. Once you’re past it, it’s just another sea story.
I joined the Navy to see the world, only to discover the world is 2/3 water! share