Circuit pattern on an aircraft carrier
 

Evening all,

I'm writing a presentation on the evolution of the aircraft carrier and would like to ask about S.O.P when an aircraft approaches the carrier to land and if there is a circuit pattern an aircraft would follow.

My understanding is that it is always flown on the port side of the ship and would be grateful if any naval aviators could confirm and expand on.

many thanks,
Chanter

Chanter, if you PM me I can email you a comprehensive guide. Good luck with your presentation, can I ask who it is for?

Regards

FNS

On an almost similar vein - what was the practical limit to a formation recovering to the ship, given the deck clear time and how far upwind you could risk the airy's going without getting lost :) - a pair?

USN T-45C Goshawk Carrier Circuit Explanation PDF
 

A current example of a 'deck landing aircraft' with good explanations and graphics would be here (with an example graphic):

http://www.cnatra.navy.mil/pubs/folder5/T45/P-1211.PDF (1.6Mb)

Click thumbnail for big picture: http://i98.photobucket.com/albums/l2...ierPattern.gif

Generic overhead carrier landing pattern view from:

https://www.cnatra.navy.mil/ebrief/d...V%20NATOPS.pdf

Click thumbnail for big picture: http://i98.photobucket.com/albums/l2...rnOverhead.gif

A good 'brit-centric' overview of NavAv would be here:

'The Particular Mechanics of Carrier Aviation' by Steve George BSc MSc CEng FRAeS Cdr RN 2012

http://www.phoenixthinktank.org/wp-c...fcaropsPTT.pdf (4.6Mb)

Alternatively there would be 2GBs of giggles about how to deck land here including history from props up to and including the F-35 flat deck landers:

https://skydrive.live.com/?cid=cbcd6...340707E6%21932

Many thanks chaps,

FNS, have sent a PM

Spaz, great diagram

Chanter

The RN pattern for VSTOL aircraft had you breaking at ten seconds past the bow with subsequent aircraft breaking 20 seconds behind you, but the spacing used to concertina up when you arrived alongside.

This sort of thing could be changed locally if the deck or an individual pilot needed more time between recoveries.

USN SOP that you have to have broken by 4 miles in front of Mum or you go around and have another go. Practically speaking this means that if you are bringing a four ball in - dash one needs to be in the break at the bow if dash four is going to be turning in time.

The whole aim is to get an aircraft into and out of the Landing Area every minute.

USN Intervals for Carrier Break Formations
 

Paddles Monthly June 2011

http://www.hrana.org/documents/Paddl...lyJune2011.pdf

COE / Blue Water Certification
CDR Marc “Stoner” Preston from Commander, Strike Force Training Atlantic (CSFTL) gave an excellent brief on Combat Operational Efficiency and "Blue Water‟ certification and how it fits into C2X. As most of us who have experienced it, we all know that C2X is basically conducting Air Wing Fallon-type missions in the CVN environment in order to test whether the CVW and CVN can cooperatively operate in such a high-tempo operational environment. This includes the standard tactical missions like Strikes, Maritime Strikes and Defenses, Air Defenses, CAS, CSAR, etcetera.

However, how does the Combat Operational Efficiency (COE) aspect come into play and what is it for? As per the CSFTL/CSFTPINST 3500.4A, COE is defined as:

“The efficiency with which a Carrier Strike Group (CSG) conducts flight opera-tions is directly related to its lethality and survivability…..Carriers and Carrier Air Wings that cannot meet established standards of efficiency incur additional exposure to surface and subsurface threats due to prolonged periods in which maneuvering is effectively precluded. Finally, pilot proficiency is directly relatable to operational safety. Since combat operations are frequently required where no divert field is available, or where divert of aircraft could result in political situations disadvantageous to the United States.”

The evaluation phase of COE consists of a two day evolution where the ship and air wing are evaluated on metrics that directly apply to the above-mentioned excerpt. During these two consecutive days, the CVW will fly greater than 90 sorties while maintaining an Event Factor and Combat Boarding Rate at prescribed standards:

- Event Factor (EF): 1.2 Case I/II and 1.75 Case III
- Combat Boarding Rate (CBR): 90% Case I/II and 85% Case III

What are Event Factor (EF) and Combat Boarding Rate (CBR)? Event Factor measures the ability for the flight deck and air wing to work together to maximize lethality and survivability. Here is how it is measured over the course of a launch and recovery:

Event Factor = (Total # of Launches + Total # of Recoveries) / (Minutes Elapsed)

For example, an event that launches 10 aircraft and recovers 10 aircraft in a 12 minute period would post an EF of 1.667 (20 divided by 12) and if the same recovery takes 15 minutes then the EF would be reduced to 1.333.

Since the necessary EF for COE certification is 1.2 for Case I/II and 1.75 Case III then how many minutes could a “10 to launch and 10 to catch” Case I event take and still meet the minimum standards for event factor? Case III? Answer: 16 minutes and 40 seconds and 11 minutes 25 seconds.

The keys to success to meet your event factor are to realize that you "make your money‟ on the launches. Having multiple catapults working at quick intervals can hopefully launch several aircraft per minute, leaving plenty of time to complete the recovery within parameters. Squadron LSOs should train their pilots to be ready to launch as you taxi to the catapult. Having to suspend for unnecessary troubleshooting, or because of improperly set trim or some other problem with takeoff checks can be very costly during COE. Walk early and stay ahead of the jet on deck!!!

Collapsing the stack and flying a disciplined Case I pattern is also paramount for success during COE. Obviously, obeying the ‟Rules to Live By‟ on the ball and getting aboard first pass are an important requirement but two other things need to be considered: aggressively (and smartly) pressing the deck and setting the proper interval.

Section and division leads should be pressing the deck in order to have the first aircraft rolling into the grove just as the flight deck completes wrapping the waist and making a ready deck. Just make sure you are not too aggressive and cause either a clogged spin pattern or widespread confusion due to multiple depart and re-enters. Squadrons responsible for breaking the deck should regularly debrief their performance. CAG Paddles need to also debrief the first pilot down on the time elapsed between the deck going clear and the first arrestment.

When considering interval, it is best to be long than short. Even though the textbook Case I/II interval is 45 seconds, during COE it is much better to be closer to 55 or even 60 seconds lest you run into too many fouled deck wave-offs. When you think about the math involved in calculating EF, the extra 10 to 15 seconds added onto each interval during the course of a recovery is very little compared to the extra time added for even a single fouled deck wave-off. All pilots should continually evaluate timing when to break based on their interval pass-to-pass in order to target than 55-60 second Case I interval.

Another important thing to not be forgotten is a solid COD recovery plan. Do not let an otherwise stellar launch and recovery evolution have its EF numbers fall below the requirements just because we forgot about the C-2s.

As for Combat Boarding Rate (CBR), it is calculated by the number of traps divided by the total number of "attempted‟ traps with 90% being the goal for Case I/II and 85% for Case III. Both metrics are related to each other due to the fact that a bolter obviously hurts both your EF as well as your CBR. Historically speaking, it tends to be a bit harder for Carrier Air Wings to achieve their Combat Boarding Rate numbers than Event Factor. Squadron LSOs need to train your Ready Rooms to consistently shoot for a 55-60 second interval vice 45 seconds, be very disciplined in the pattern, and to safely get aboard on the first pass while not violating the "Rules to Live By.‟

In an old 60's nutshell:

Down the starboard side of the carrier at 400ft - echelon starboard if more than one. Break in front of carrier and turn left downwind. Turn base abeam the stern and fly around on finals. Pick up the mirror and go for the deck.

1958
 

4greens,
that's more like it
I seem to remember a 2 second break and aiming for not more than 15 seconds apart at the round down ?
these youngsters don't know they're born !
AA

Charlie Time was for the first aircraft crossing the roundown, so that at the break the ship was probably still turning into wind. And never start descent (from 400 or 450 ft circuit height) until you've got the mirror (projector sight/fresnel lens) - especially at night. PS if the interval is more than 15 secs it was probably a Gannet. :) LFH

Semi-Circular base leg
 

In about 1991 I flew as a passenger on American Airlines Chicago to DFW. The flight was much delayed due to an incorrect warning light and eventually we departed after boarding the passengers for the next flight too - or maybe we changed aircraft I forget. I think that the aircraft was a DC-10 or Lockheed Tristar. The same type did the Glasgow-Chicago leg. (Wiki, she say AA had DC-10 and not Tristar.)

The flight crew announced that they would try to catch up towards the schedule.

On arrival near DFW the flight crew announced something about co-operation from ATC allowing a landing without holding.

I was surprised when I saw a runway out of the window (left I think) that seemed much closer that I would have expected for an airliner. It turned out that we were on the downwind leg of a circuit to land on that runway. It was not much different from what I had experienced in the Cessna 150 and Chipmunk which I had flown some years previously. The aircraft then executed a semi-circular base leg and rolled level smack on position for short final and landing. It was all very smooth and I felt that the pilot had exhibited astonishing judgement in order to accomplish the final approach and landing in this manner.

Many years later I saw a TV program about carrier operations and thought that I recognised the approach. Now this thread has reminded me of it again.

We did seem to catch up very nearly to schedule after a delay of perhaps two hours. I was astonished.

Just to be clear I at no time felt unsafe. It appeared to be beautifully flown with no abrupt changes of any kind. The pilot clearly knew exactly what he was doing.

I guess the pilot might have been ex-navy? Does anyone else use these semi-circular base leg approaches? I wondered what the management might have thought of the approach? What would they think of such an approach today?

Executable files on skydrive - SpazSinbad
 

Dear SpazSinbad,

Thanks for the documents, very interesting.

I was going to have a look at the skydrive material but when I noticed that the "part1" file was an application (*.exe) I called off.

I don't think anyone should be downloading and running executables off of the internet unless from a trusted source due to the risk of running malicious code. Sadly dear SS your credentials do not meet my requirements:-)

I am prepared to download and unpack zip or rar files.

Hope you find this helpful.

I am NOT suggesting that SS is attempting to introduce bad code. I am simply saying that this is an excellent way of propagating viruses that may exist on one computer to another computer.

Jim.

'jimjim1' the .RAR archive is an SFX one. If you have a reputable antivirus program you should feel protected. I would recommend Microsoft Security Essentials because it is free and excellent. But then again I'm only a malware vendor eh. Sad indeed. It is possible to make all the .RAR archive .RAR files but then I'm told people can get confused about what to do - so having an .exe file helps them - obviously not with you. But thanks for bringing your concerns to my attention. Others on this forum having downloaded the files mentioned that they were crap so you have not missed much anyway.

:):
Surprised someone called 4greens is not jumping down the ancient one's throat!:) If the 4 greened youngsters didn't have the whole 4 ship on deck within 15 seconds they were likely to get a summons to flyco for a one way chat from Wings!:)

If you chaps can think of a way to get a 40 plus thousand pound machine out of the wires and clear of the LA in 15 seconds I'm all ears!;)

Don't have my copy of Wings On My Sleeve handy but the 'no gear - rubber deck- down the chute and into the hangar' idea might work I suppose. Can't remember exactly how they were going to crack it.

Having been part of two 'four green' communities - one with a green for each wheel, the other with a green for three wheels and a hook - I can safely say that the former was definitely the most forgiving of interval variations - if the chap in front was having a drama you could simply hang out over the ogsplosh and wait for him to sort it out.

Whilst watching your water and fuel run out and the engine temperature doing its 'rat up a drain pipe' impression!

Caught the wires once just as 'Mother' was turning out of the wind. Didn't quite go over the side. The Captain called me to the bridge and apologised, which was nice of him. Never a dull moment.

@jimjim1 FYI semi- circular base legs are quite standard in airliner ops with a constant descent and change of config on the way round. Fun to do but don't get the chance often enough!

Page 32/33 in Buccaneer S1 from in the cockpit by Michael j Doust has all the info and a diagram for a carrier landing ;)

- silence noted (and I'd love to see some video of '15 second spacing')