DCS F-18 - Holding Pattern Procedure

[VBF-12 Gosling]

Chaps

I AM REVAMPING THIS THREAD COMPLETELY, IN THE LIGHT OF THE UPDATE FACILITiES PROVIDED BY THE SUPER CARIER AND OUR BETTER KNOWLEDGE OF CARRIER CASE 3 PROCEDURES

A holding pattern is a skill in its own right. It is used for awaiting recovery, awaiting task “Push” time like time on to target for close air support etc.

It can be split into parts

• Basic Hold Pattern
• Entering the hold
• Maintaing the hold - Wind
• Adjusting hold timing

Referencre:
a. P-1204 Flight Training Instruction, Instrument T-45 MPTS and IUT Rev. 3 - Paragraph 607 on Page 6-32
b. F18-ABCD-000 NATOPS FLIGHT MANUAL NAVY MODEL F/A-18A/B/C/D AIRCRAFT - Chapter 19, Paragraph 19.1.3.2 on Page VI-19-1

BASIC HOLD PATTERN
The hold is a racetrack pattern and is usually 4 minutes in duration. 1 minute for each side and 1 minute for each turn. This is the classic “Rate One” turn which at 3 degrees / second completes 180 degrees in 1 minute.

However, the hold for Naval Operations is not like this! It is a 2 minute turn which equates to a Rate 0.5 turn. (Ref a.)

Also, for the F-18 the endurance speed (at which Holds should be flown in Naval Operations) is between 220-240 kts Indicated Air Speed (KIAS). (Ref b.)

Rate Half Turn
To achieve a Rate ONE Turn requires a different Angle of Bank (AoB) for different speeds.

Rate ONE Turn Rule of Thumb: AoB = 15% of IAS = 1.5 x (IAS / 10) So, a tenth of IAS plus half of that

Eg: Rate One AoB for 240kts is: 240 / 10 = 24 Now add half of the result. 24 + (24 / 2) = 24 + 12 = 36 degrees AoB

Rate HALF Turn Rule of Thumb: Rate ONE AoB / 2

So to achieve a Rate HALF turn = [ 1.5 x (240 / 10) ] / 2 = 36 / 2 = <b>18 degrees</b>

[VBF-12 Gosling]

ENTERING THE HOLD

Types
This is split into three types: Direct, Teardrop and Parallel

Standard holds are a right hand hold. Our Case 3 is a Non Standard left hand hold however. No problem, its a matter of choosing the reflected version of the join.

DIRECT JOIN (c)
Centre Diagram. It is the basic join and the one used the majority of the time.
Inbound Track. The “Inbound Track” is always towards the ship, airfield or target. Up the diagram above.
The Direct join is the bottom hemisphere, but it is not divided exactly top and bottom. It’s on a slant by 20 degrees (Correction) on the inside of the hold.
Joining. To “Direct Join” just fly to the waypoint / TACAN and turn into the hold. There are timing adjustments to make your role out onto the downwind heading more accurate but at our speeds it makes little difference.



TEARDROP JOIN (b)
Right Diagram. Now we are dealing with part of the other hemisphere. Think of this one as joining from the OUTSIDE FRONT corner. As the hemisphere division is offset by 20 degrees on the inside as described above, the “Teardrop Join” is only the Outside Front 70 degrees.
Joining. Come over the Waypoint / TACAN and head for the diagonally opposite corner of the hold pattern 30 degree offset from the OUTBOUND LEG (ie 180 from the inbound Track).

PARALLEL JOIN (a)
Left Diagram. The final part is the remaining 110 degrees and can be thought of as the FRONT INSiDE Corner. From the Inboud track round to 20 degree beyond the abeam. For this, fly to the Waypoint / TACAN and turn the WRONG WAY to fly down the inbound leg BACKWARDS!!! Then turn within the hold (ie right for a left hold) and again fly DIRECT (diagonally across the hold) to the Waypoint / TACAN. Finally, turn the correct way to HOLD>.

Join Summary
Arriving from behind the hold - DIRECT - Fly to Wpt and take up hold
Arriving from opposite side and in front of the hold - TEARDROP - Fly to Wpt and diagonally across then hold
Arriving from same side and in front of the hold - PARALLEL - Fly Wpt, backwards down the inbound track, continue around the wrong way, then cut diagonally back across directly to Wpt and take up hold inn the correct direction. (Left for Case 3)

[VBF-12 Gosling]

MAINTAINING THE HOLD - WIND

Wind from Ahead
So from memory, it is: Deduct 1 second from the outbound leg for every 1 knot of tailwind. This is approximate and does not seem to result in an accurate solution, but is good enough.

It seems that it is best to fly the hold at <b>220-240 kts Ground Speed</b> (Shown in the DDI on the HSI Page). So that is about 4 nn / min. The reason for 220 Kts is because True Air Speed (TAS) increases with height by about 2 kts / 1000 ft. So, 220 IAS = 240 TAS at 10,000 ft approximately.

So a 6 minute hold at 220 kts IAS (approx 240 kts TAS - 4 nm / min) on a calm day has outbound and inbound legs of 4 nm.

So, with a 30 knot wind from ahead on the inbound leg.....

• The wind will speed up the ground speed of the outbound leg.
• It will drift the aircraft downwind on both the first turn and the turn back inbound by a mile each.
• It will slow down ground speed of the inbound leg.

So, all in all the hold takes longer unless we shorten the outbound leg.

Rule of Thumb: Deduct 1 sec / 1 knot of tailwind outbound from the outbound leg timing.

A 30 knot tailwind makes the outbound leg time = 1:00 - 0:30 = 0:30 secs.

We have to consider the effect of the wind during a full hold:

• 30 kts wind - 0.5 nm / min - The aircraft will drift downwind by 3 nm
• Calm wind - 0 nm / mins - The aircraft does not drift downwind

Ships Movement. This also has to be considered:

• 30 kts - 0.5 nm / min - The ship moves away from the hold pattern by 3 nm
• 15 kts - 0.25 nm / min - The ship moves away from the hold pattern by 1.5 nm

So, working around the pattern with a steady 240Kt TAS, a wind speed of 30 kts and a ship speed of 30 kts.
First Turn. In the 2:00 minute turn, we end it 1.0 nm downwind from the abeam point.
Outbound. We fly 2 nm for the 0:30 (leg time reduced by wind speed in seconds) and a further 0.25 nm, as a result of following wind, during that 0:30s. Total so far = 3.25 nm
Turn inbound. We drift a further 1.0 nm down wind during the 2:00 minute inbound turn.
So we start the inbound leg at 4.25 nm from the <b>Original Wpt</b>.
Ship Movement. However, during this time the Ship is sailing away from us. It will have sailed at 0.5 nm / min. In the 4:30 mins so far it will have sailed away 2.25 nm.
Inbound. At the start of the inbound leg, to make the <b>New Wpt</b> with our AIR SPEED at 4 nm / min, we must cover 6.5 nm plus the 1.0 nm the ship will sail during the inbound leg. So the final total = 8.0 nm. This takes 2:00 min. Add 1.0 nm for the ships movement and 0.8 nm of opposing wind on that leg = 23 seconds adds 0:04 secs.

This makes the total time around the hold of 2 + 0:30 + 2 + 2:00 + 0:04 = 6:30. A bit long! But it is a very strong wind as you will have 60 kts over the deck.

Considering this is an approximation, it’s not too bad.

Wind from Abeam
This should be much less as the carrier / airfield will have the hold largely into wind. But there is likely to be some...

Work out the outbound drift using Max Drift and Clock Code.

MAX DRIFT

MAX DRIFT = WIND SPEED / AIR SPEED ( in nm / min )

A 30 knot wind has a Max Drift of 30/4 = 7.5 degrees (call it 8)

CLOCK CODE

Proportion of Max Drift to use is the Proportion of an hour of the wind angle degrees from ahead as minutes on a clock

So, If the wind is 30 degrees angled from the inbound track then that equates to a Clock Code of 30 mins or half an hour so use half of the Max Drift = 4 degrees approx.

Lets say the wind was from the right of the inbound track of a left hand hold.

• Wind will blow us right of the outbound track and we will need to over turn the first turn by 3 degrees to track down the outbound leg accurately.
• Similarly on the inbound leg we will again need 3 degrees, this time under turning the turn back onto the inbound leg.
• But what about the turns? The first turn takes twice as long and the wind is blowing us wider than the we expect so the outbound track would be along a line stepped out from the clam wind track. Also, during the turn back inbound the turn takes 2:00 mins time and thus the track will end up to the stepped narrower inside of the calm inbound track. To compensate for this we need to allow 5 times the outbound drift offset. So for our example over turn the first leg by 5 x 3 = 15 degrees.

Maintaining the Hold Summary
So the final solution is:

REDUCE the OUTBOUND leg by ONE SEC / KNOT of headwind and fly OUTBOUND leg OFFSET by 5 TIMES the DRIFT.

As you roll out into wind adjust to fly on the inbound track with the 3 degrees of drift to maintain that track to the waypoint.

[VBF-12 Gosling]

ADJUSTING HOLD TIMING

With Case 3 the aircraft should leave the hold and descend with the procedure at a certain time (+/- 10 secs). This is tricky... It’s affected by the wind again.

Again, try to fix the timing on the outbound leg, so if you are late reduce the outbound leg by 1/2 the time late, adjusted for wind.

Rule of Thumb: Deduct 1/2 the time late - 1/2 the windspeed

If you go over the beacon at 5 mins to go you will be a minutes late. Fly outbound for 0:30 in calm conditions. Thus the timing is 2 + 0:30 + 2 + 0:30 = 5:00 mins

However the ship may have moved by 2.5 nm in that 5 mins if it is doing 30 kts

1 min late on a windy day (30kts) fly outbound for 1 - 0:30(Wind) - 0:30(Timing) = 0:00
Working around this pattern:
First Turn: Downwind drift by 1.0 nm in 2:00 min
No Outbound Leg
Turn Inbound: Downwind drift by 1.0 nm in 2:00 min
Inbound Leg: 2.0 nm and 0:30 min plus 0.25 nm is 0:03 min
Ships movement 2.0 nm and so 0:30 plus another 0.25 nm is 0:03 min
Total time = 5:06 secs - So you have caught up the time just about.

Of course if you are early at the waypoint extend the downwind leg by 1/2 the wind speed.

Basically, make timing adjustments downwind. With wind and ships speed you are always loosing ground...

[VBF-12 Gosling]

Okay - I am going to start this thread again as we have new information on how the pilots actually do the hold.

It is not something specifically defined and they are allowed to solve the issue of commencing their approach on time however they like.

However, Waggs demonstrates one method in the Case 3 Comms for the USS Nimitz below:



Basically, fudge it and fly to make the timing.

Hold should be left for Marshal stack and right for the Emergency stack (covered later)

The protected area is 30 degrees left and 10 degrees right on the Marshal Radial, so don't alter height within that cone.

[VBF-12 Gosling]

CARRIER HOLD

There are three main problems with holding in the stack for a CASE 3 recovery at the carrier:

Wind - Well the carrier is usually turned into wind but the wind at 10,000ft may be different. The above compensation work well. To adjust the leg timing the aircraft should be flown at 220kts KIAS, but flying a set Ground Speed as indicated on the HSI to the right of the Aircraft Symbol may work better for you.

Timing - The Descent should be made at the correct range and the correct time so the hold must be adjusted to achieve this.

Ship Movement - The ship is steaming away from your hold at 25-30 knots and slightly (9 degrees) to the right. So the Descent point is further away after a hold than when you started.

Carrier Case 3 Hold Pattern

• Speed: 220 Kts IAS
• Turns: 18 Degrees Angle of Bank
• Legs: 4 nm
• Time in Turn: 2:00 min
• Time on Leg: 1:00 min

With ships movement, this equates to approximately a 7 Minute Pattern !

Adjusting Timing - How much time left before EAT?

• Less than 4 min - Do one tight circle turn:
  • - 18 AoB = 4:30, with ship movement (Rate 0.5 Standard)
  • - 27 AoB = 3:22, with ship movement
  • - 36 AoB = 2:15, with ship movement (Rate 1)
  • - 45 AoB = 1:45, with ship movement
  • - 54 AoB = 1:30, with ship movement (Rate 1.5)
  • - 63 AoB = 1:36, with ship movement
  • - 72 AoB = 0:30, with ship movement (Rate 2)
  • Less than 30 sec - Go Now
• Less than 7 mins - Start hold and turn early
• More than 7 mins - Start hold, divide time to go by 2 and complete two holds

Leg time:

• (Hold time - 3 mins) / 2

Adjusting for ship movement - For a 7 min pattern the ship will have moved which must be allowed for:

Ship Movement:

• 30 Kts - 3.5nm = 1:45 @ 300 Kts GS
• 25 kts - 3nm = 1:30 @ 300kts GS

So the inbound leg is 13.5nm instead of 10nm.
To help with this the Outbound leg can be shortened by 1 nm (ie turn after 1:48 on leg = 3:18 after starting the turn).
This reduces the inbound leg to 12.5nm with an extra 12 seconds available having rolled out inbound.
So 11.5nm in the last two mins to be flown = 345 knots G/S.

As you roll out inbound a final correction may be required -

Roll Out Inbound Timing:

• Ship: Add Ship’s Speed straight away
• Rng difference (from 10 nm): +/- 30 kts / nm (10% Rng)
• Time difference (from 2 mins): +/- 15 kts / 6 secs (5% time)

Reqd GS	1:48	1:54	2:00	2:06	2:12
12nm	400	378	360	342	327
11nm	366	347	330	314	300
10nm	333	315	300	285	272
9nm	300	284	270	257	245
8nm	266	253	240	228	218

PLUS ship’s speed - to allow for the ship distance over the inbound leg time.

[Garf]

Awesome Info - Many Thanks!!!

[VBF-12 Gosling]

May 24, 2020 5:50:10 GMT -5 Garf said:

Awesome Info - Many Thanks!!!

I’m going to rewrite this in a simpler way.

DO NOT FOLLOW the GR guidance video. He does not know what he is doing and makes it up as if it’s the real thing.

Don’t get me started in his Helo v fighter tactics!!!!! I’ve fought of (exercises) Tornados, Hawks and F-16s in RL...