how to fly a holding pattern

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    How to. Fly a Holdby Jacques Zahar, CFI(Note this page is best viewed with a 1024X768 resolution)

    Basically, a Hold is for airplanes like a stoplight for cars. Except that you cant put the parking brake on in

    flight.

    The purpose is to have the plane wait at a specified part of airspace (Protected airspace) until the trafficahead of your plane is far away enough or has landed.

    Though Holding instructions are seldom ever used under the Procontroller/Squawkbox virtual ATC environment,

    on very congested areas (Fly-ins) or simply for practice, it can be interesting both for ATC and Pilot if Hold is

    accepted and flown.

    The purpose of these pages is to give Virtual Pilots a way to fly a Hold manually.

    This section will be divided into 4 sections:

    1- Holding Clearances: How to decipher holding clearances

    2- Types of entry: Depending on your location, how to enter a holding pattern properly

    3- Flying a Hold: Principles of holding

    4- Exiting a Hold: What to do next?

    Before having a look at holding clearances, lets see the basic elements of a Holding pattern :

    Without crosswind, a Holding pattern is like a racetrack:

    See the arrows? They indicate the turn direction. A holding pattern with right turns is called a standard hold, one

    with left turns is called a non-standard hold. This is important to know, as some ATC can say standard instead

    of right turns or assume that the hold will be standard if they dont specify the direction of the turns.

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    See also the inbound leg: this is the leg to which ATC refers to when giving the clearance, it is always going to

    and finishing at the holding fix. The inbound leg should be flown forONE minute if below 14000 feet orONE

    minute if above 14000feet unless otherwise specified. The outbound leg is not timed and depending on thewind can take more or less time than the inbound leg.

    Note that ATC can also give DMEHolds, in which case ATC will specify the distances from the navigation aid at

    which the inbound and outbound legs are to be terminated. In this case no timing should occur, since the DME

    distances given describe the end of the inbound leg and the start of the turn outbound, and the end of the

    outbound leg and the start of the turn inbound.

    Last, look at the turns. No radius is specified here since they are all standard rate turns (3 per second) in a hold.Its time to use the small airplane of your turn coordinator !

    1- Holding clearances:

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    Note that not all holds are issued by ATC. One can have to hold without specific instructions if the last point you

    have been cleared to is reached without further ATC instructions (ATC is sometimes busy) or when

    communications have been lost. In that case use a standard pattern (right turns) upon reaching the lastassigned fix.

    ATC issues holding instructions in the following form:- Geographical reference of the Holding fix: the general location of the holding

    - Inbound leg: the inbound leg is always the reference

    - Turn direction: (right turns (standard) or left turns (non-standard)

    -

    Altitude- Expected further clearance time (EFC)

    - Current time (optional)

    For example: C-GSRW, hold north-west of the Mirabel VOR on the 330 degrees radial, left turns, maintain 5000

    feet, expect further clearance at 1730, time is 1712

    hold north-west

    The general direction of the holding patterns inbound leg in reference of the holding fix, using geographical

    directions (N, NE, E, SE, S, SW, W, NW,)

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    the Mirabel VOR..The holding fix. This can be a VOR, an NDB, or a Fix

    (intersection)

    or even a Marker beacon.

    A holding fix can also be defined via DME distances,

    in that instance a radial and DM

    E distance are given.

    on the 330 degrees radial

    The track upon which the holding patterns inbound leg is

    located

    left turns

    Obvious. Note that the turns used to enter the hold are not considered.

    Once you are established in the hold, all your turns will be as instructed,in our case this one is a non-standard pattern.

    maintain 5000 feet

    the assigned altitude

    expect further clearance at 1730..

    the expected departure time from the holding fix.

    This doesnt necessarily means that youll be leaving the hold at that time (ATC can release you earlier atanytime), but in case of lost radio communications during the hold, you are expected to hold until the EFC and

    proceed as filed or land if it was planned. So before accepting a holding clearance (by reading it back),

    always check your remaining fuel and NEVER accept EFC that can compromise your fuel reserves and

    alternate airport requirement.

    Note: sometimes ATC can issue abbreviated holding instructions, if the hold is published on the HI/LO maps or

    the approach plates. In that case it will simply say as published or as charted.

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    Okay, weve copied and readback the holding clearance, now its time to figure out where and how to enter

    this pattern.

    1-The first thing to do upon receiving an holding clearance is to check the EFC against the remaining fuel.

    2-The second is to reduce airspeed if you are within 3 minutes of the holding fix or ask the ATC for a speed

    reduction if you are further than 3 minutes. Holdings are here to have you to wait, so why not reduce your

    speed ASAP and save fuel at the same time? If youre lucky, by the time you have reached the holding fix at

    reduced speed, the hold wont be needed anymore!

    Moreover the extra time will help you figure out where

    you are from the fix, and how to enter the holding

    pattern.

    There is a holding speed limitation in a Hold, based on

    the following limitations (Note: this is based on

    Canadian regulations, check your local ones).

    IAS stands for Indicated airspeed, in knots.

    3-The third thing is to fly direct the holding fix, in order to

    become oriented and set-up the entry procedure.

    Heres an easy way to visualize where is the Holding

    pattern considering your position, by using your

    directional gyro (DG) or your Horizontal situation

    Propeller

    aircrafts(including

    turboprops)

    175 Kts IAS

    Civil turbojets230 Kts IAS below 14000ft

    265 Kts IAS above 14000ft

    Military turbojets 265 Kts IASClimbing in holds 310 Kts IAS or less (jets)

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    indicator (

    HSI) : The Holding fix is located at the centre of the DG or your HSI, and you are at the bottom of the instrument

    heading toward the fix. Now locate the radial or bearing from the holding fix on the HSI: this is the inbound leg.Then visualize the racetrack according to the type of turns.

    2-Types of entry:

    Once we figured out where is this holding pattern, let talk about types of entry.

    There are three types of entry, depending on your location when approaching the holding fix.

    Divide the airspace in two parts along the inbound leg of the hold (1), then at right angle starting from the fix

    (2). Lastly, tilt the line N2, 20 degrees down to the side of the holding pattern (3). You end up creating four

    sectors (actually three) which give you the type of entries required.

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    Direct Entry

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    Parallel Entry

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    Teardrop Entry

    Since we visualize the holding pattern directly on the DG or HSI, the entry method and the headings to followbecome straightforward.

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    In our last example (a nonstandard holding

    pattern on the 330 degrees radial), we would

    have to fly a teardrop entry, i.e. fly direct to

    the fix from the South with a 360 heading,

    then upon passing the fix (the VOR flagchanges from TO to FROM), we fly the 360

    degrees heading (330 degrees PLUS 30

    degrees ) and start the timer for one minute,

    then turn left (standard rate turn) to intercept

    and track the 330 radial of YMX VOR and

    enter the hold.

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    Lets say we are heading from the West in a

    090 heading. This time we have to perform a

    direct entry, i.e. we fly direct to the fix with a

    090 heading, then upon passing the fix (the

    VOR/HSI flag changes from TO to FROM), we

    turn outbound on the 330 heading with astandard rate left turn. When we level off the

    turn, we start the timer for one minute, and

    then we go. At the end of one minute (plus or

    minus the wind correction), we start the turn to

    intercept and track the 330 radial inbound

    and enter the hold.

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    Here we are flying direct the VOR from the

    East on a 240 heading. Our position calls for a

    parallel entry, i.e. we fly direct the VOR with a

    240 heading, then upon passing the fix (the

    VOR/HSI flag changes from TO to FROM), weturn right to a heading 330 so we fly parallel to

    the inbound course and start the timer for one

    minute, then turn right (notice the difference

    with the other type of entries) to intercept

    and track inbound the 330 radial and enter

    the hold.

    Practice a little bit using this method and avoid drawing anything on a piece of paper. When youre flying in

    the clouds your eyes should be on the instruments and seldom elsewhere!The trick is to VISUALIZEand PRACTICE.

    3-Flying the holdNow its time to relax and let the autopilot do the job No just kidding, unless you fly one of these all-

    computerized FMS machines that can do a Hold with a simple couple of keystrokes

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    Once youve entered the Hold either way, you should be flying inbound the fix, tracking the VOR radial or

    the NDB inbound course. You have to remember that a Hold is (in most cases) one minute long on the

    inbound leg when below 14000feet or 1 minute when above 14000feet.

    In order to reach that goal, and keep the ATC happy, we have to account for the wind. We will have to

    compensate for headwind or tailwind by adjusting the outbound leg so the inbound leg is one minute or

    one minute long.

    When to start the timer?

    For the inbound leg:

    - As soon as you roll out from the inbound turn out OR intercept the inbound track, start the timer.

    - When abeam the station at a VOR (the flag changes from TO to FROM) or a NDB (The needle flips from

    the nose to the tail), stop the timer.

    For the outbound leg:

    -If the Holding fix is a VOR, when the TO-FROM indicator changes from FROM to TO, start the timer.

    -If the holding fix is a NDB, when the needle points (with no wind) 90 degrees to the left or the right, i.e.

    points to the wingtip, start the timer.

    Turns are never timed, as they are standard rate turns.

    You end the outbound time and start the inbound turn depending on the wind.

    Adjusting the outbound leg.

    If you dont know the winds aloft, fly the first pattern with a one minute outbound leg. Then measure the

    time required to fly the inbound leg. For the second pattern, fly the outbound leg by adding or

    substracting to one minute the difference between one minute and the time you flew the inbound leg.

    Confused? An example will make it clear.

    If the first outbound leg was 1 minute and the inbound leg took30 seconds, fly the next outbound

    leg for 1 minute (60sec+30sec). (Headwind on the outbound leg, see the example below)

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    If the first outbound leg was 1 minute and the inbound leg took1 minute and 15 seconds, fly the

    next outbound leg for 45 seconds (60sec-15sec). (Headwind on the inbound leg)

    Wind correction and Crosswind.

    In a perfect world, there would no be crosswinds. But in real world (and even in simulation!) the crosswind is

    something to be accounted for in a Hold.

    Since both turns are standard rate, a crosswind causes the downwind turn to have a larger radius than the

    upwind turn.

    So the racetrack looks now more an egg shaped oval when crosswind is involved.

    Now you have your answer ready when ATC calls in and ask the reason for the strange pattern youre drawing

    on his scope!

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    So obviously one have to fly the pattern while correcting for the wind.

    The rule of thumb is to double the inbound leg wind correction angle on the outbound leg.

    On the inbound leg, track the VOR radial and use whatever correction angle is needed to compensate the

    drift and stay on course. Note the wind correction angle you are using.

    So if you had to fly a 100 degrees heading (1) to stay on course inbound of a 270 radial (90+10 degrees wind

    correction angle), in order to compensate for a crosswind coming from your right, you will fly a 250 degrees

    heading (2) outbound (270-(2*10 degrees)) for the outbound leg.

    4-Exiting the holdAfter a couple of turns, the ATC will probably release you from the hold (at last!)

    But if youre five minutes from the EFC time, ask the ATC for a clearance (hes probably asleep), as you need

    to know what to do next. He will then clear you for another Hold (oh nooo!), have you descend to another

    altitude and hold(Shuttle Hold, more on that later), or give you radar vectors to proceed direct to the

    approach.

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    In case of radio communication failure, squawk 7600, hold until reaching the EFC time, then proceed as filed,

    i.e. fly the full approach or proceed to the next waypoint on your route.

    In all cases, try and adjust your speed so you leave the Holding pattern as close as possible as the EFC timeyouve been given in the holding clearance.

    Shuttle procedure.

    A shuttle procedure is a maneuver involving a descent or climb in a pattern similar to a holding pattern. It is

    used on instrument procedures located in mountainous areas, or for certain types of missed approaches, or

    when ATC clears a plane, located below in a stack, for the approach and instructs the planes holding in the

    same airspace to descend one step further.

    The maneuver is flown exactly the same as a holding pattern, except that descent will occur within the

    inbound or the outbound leg. In order to prevent the airplane from exiting the protected airspace, speed is

    restricted to 200kts IAS.

    Enjoy the flight!

    Jacques Zahar

    ICAO CPL/ multi/IR flight instructor

    The material exposed here is copyrighted and should not be used without written permission from the author.For comments or suggestions write to Jacques Zahar.