Holding Pattern Computer-V3.0

Aviation Mobile Apps Holding Pattern Computer-V3.0 What’s New?

Les Glatt, PhD, ATP November 1, 2023

What is Missing in the Holding Pattern App V2.1

• What capabilities are in V2.1? rd
• The HPS/EFC Methodology was Completed in 3 quarter of 2020

• Providesoutboundheadingandoutboundtimetodeterminethegroundtrackthatallowsthe A/C to intercept the holding radial with the specified inbound time or inbound ATD

• Constantarbitraryrateofturnduringturningsegments

• Windcorrectionusedonlyoninboundandoutboundlegs

• Unique ground track for wind speed ratio less than unity

• Capability to allow A/C to return to holding fix at the EFC time given in the holding clearance

• Uses FAA Entry Recommendations in AIM

• What capability is missing from the HPS/EFC analysis that would be required for a Unified Advanced Technology Method for flying the hold?

• A“HighPrecisionEntry”capabilitytoreplacetheoutdatedFAA/AIMentryrecommendations

  • Fly direct to the holding fix or fly along a DME arc to the holding fix

  • Cross the fix, turn outbound to a specified outbound heading and outbound time

  • Turn inbound to a specified heading and intercept the holding radial

• Target intercept point on the holding radial is the specified inbound time or inbound ATD

Introducing the High Precision Entry (HPE) Method

• In 2021 developed the High Precision Entry (HPE) Method for entering the holding pattern

• Instrument Pilot ACS treats the entry phase and holding phase as two separate skills

• HPSisjustanentryalongtheholdingradial
• Thus,HoldingPatternTheoryisallaboutentries

• HPE method asks the question:

• Is it possible to fly a heading direct to the holding fix or along a DME arc to the fix, and after crossing the holding fix, turn outbound to a specified heading, fly that heading for a prescribed length of time, turn inbound to a specified heading and intercept the holding radial at the required inbound time or ATD to the holding fix?

Introducing the High Precision Entry (HPE) Method (Cont.)

• The answer to this question is given in two parts • Can the A/C always intercept the holding radial? YES

  • Can the A/C always intercept the holding radial at the target point?- Not always

    • Cantheerrorintheinterceptpointontheholdingradialbeminimized?–YES

    • In general the target intercept point will be achieved

    • Under conditions where the wind speed ratio is large with a tailwind on the outbound leg, the intercept point on the holding radial will be slightly outside the target point. The HPE methodology will minimize this error.

    • This is not a failure of the method since once established on the holding radial the A/C will cross the fix and fly the HPS , which allows the A/C to always intercept the holding radial at the target intercept point

  • Since the HPS solution is unique, any entry solution that attempts to intercept the holding radial at the precise required inbound point, must smoothly blend into the HPS ground track

  • HPE follows the FAA/AIM recommendations for Direct, Teardrop, and Parallel entry methods, except does not use the FAA recommended outbound headings and outbound times for each entry method.

FAA Holding Pattern Entry Procedures AIM 5-3-8

Demonstrate HPE and Compare with FAA Method for Direct
Teardrop
Parallel
HPE:New Hybrid Parallel/Teardrop Entry Method

180-deg Radial Inbound Course=360 deg

HPE Entry Guidelines

• HPE provides turn by turn directions for each leg of the entry procedure

• A/C heading for leg
• Time along the leg
• Turning time for the leg • Next leg heading

• Direct or Teardrop Entry

• Provides outbound heading and outbound time after which the A/C turns inbound to a heading corresponding to the inbound course plus the inbound wind correction angle (IWCA) and intercepts the holding radial at the target intercept point or slightly outside the target intercept point

HPE Entry Guidelines (Cont.)

• Parallel Entry

• Involves 4 unknowns

• Initialoutboundheading

• Initialoutboundtime

• Interceptangletotheholdingradial

• Timealongtheinterceptlegbeforeturninginboundtoaheadingcorrespondingtothe inbound course plus the inbound wind correction angle (IWCA)

• HPE analysis determines the resultant ground track for the entry using the following requirements

• Intercepttheholdingradial

• Minimizetheerrorbetweentheinterceptpointandthetargetinterceptpoint

• Interceptangleischosentobe45-degrees

• Algorithm adjusts the initial outbound heading to minimize the error between the actual intercept point and the target intercept point

• Algorithmcalculatestherequiredtimealongtheinitialoutboundlegandtimetoflyalongthe 45-degree intercept leg before turning inbound to intercept the holding radial

HPE Entry Guidelines (Cont.)

• V3.0 introduces a new Hybrid Parallel/Teardrop entry method which can be used in place of the HPE Parallel entry method

  • Advantages-Minimizestheairspaceusedtoenterthehold

  • InitialturncontinuespasttheHPEParallelentrymethodandallowstheA/Ctocrossthe

    holding radial and enter the holding pattern using a teardrop entry method

    • When a Parallel entry method is identified, the algorithm runs 3 cases to determine the minimum entry time to get back to the holding fix

    • HPEwiththetargetinboundtimeorATDtotheholdingfix • HPEwithaone-minuteinboundtimetotheholdingfix
    • HPEwithHybridParallel/Teardropentrymethod

Comparison of FAA and HPE Entry Methods

• Scenario to compare the FAA recommended entry method and the HPE methodology

  • HoldingSouthonthe180radial

  • Rightturns

  • Altitude=6000MSL

  • KTAS=100,

  • WindDirection=045deg

  • WindSpeed=30K,

  • TurnRate=3deg/sec

  • Required Inbound Time=one-minute

    • Compare entries for Direct, Teardrop, and Parallel entries using both FAA entry method and HPE method

Direct Entry Using FAA Recommendation AIM 5-3-8

  • Aircraft heading to the holding fix is 300 deg

  • FAA entry is a Direct entry

  • Aircraft turns outbound to a heading of 180 deg for 60 sec

  • Aircraft turns inbound to roll out on heading of inbound course (360 deg) plus the wind correction angle (IWCA is 12 deg to the right, i.e. heading 012 deg)

  • At completion of inbound turn the track angle error is 32 deg

  • At this point the Pilot’s options are to either attempt to intercept the holding radial or proceed direct to the holding fix and start another Direct entry attempt

Direct Entry Using High Precision Entry Method

• Aircraft heading to holding fix is 300 deg

• High Precision Entry

  • A/C crosses holding fix and turns right to heading of 115 deg

  • A/C flies heading 115 deg for 57 seconds

  • A/C then rolls into a standard rate turn and rolls out on a heading given by the inbound course plus 12 deg IWCA

  • A/C ground track during entry phase smoothly blends into the ground track of the HPS, corresponding to the given TAS, wind direction, wind speed and require one- minute inbound time

  • Pilot workload considerably reduced

FAA Recommendation for Teardrop Entry

  • Aircraft heading to holding fix is 165 deg

  • FAA entry is a Teardrop entry

  • After crossing the holding fix A/C turns left to heading of 150 deg and flies outbound for 60 sec

  • When A/C turns to heading 012 deg the track angle error is 20 deg

  • At this point A/C options are to either attempt to intercept the holding radial or proceed direct to the fix and start a Direct entry attempt

Teardrop Entry Using High Precision Entry into the Holding Pattern

• Aircraft heading to holding fix is 165 deg

• High Precision Entry

• A/C crosses holding fix and turns left to heading of 049 deg
• A/C flies 049 deg for 12 sec
• A/C rolls into standard rate turn to the right and rolls out on heading 012 deg • A/C intercepts holding radial at the target intercept point
• Pilot workload considerably reduced

FAA Recommendation for Parallel Entry

  • Aircraft heading to holding fix is 205 deg

  • FAA entry is a Parallel entry

  • After crossing the holding fix A/C turns left to heading of 180 plus an additional 12 deg to compensate for wind (i.e. A/C parallels holding radial with heading of 168 deg) for 60 sec

  • Aircraft turns left and rolls out on an intercept angle to the holding radial (i.e. 45 deg- A/C heading is 315 deg)

  • A/C intercepts holding radial and tracks inbound to holding fix

  • Inbound time to holding fix is 91 seconds from point A/C intercepts holding radial

    • Target inbound time is 60 seconds

Parallel Entry Using a High Precision Entry into the Holding Pattern

• Aircraft heading to holding fix is 205 deg

• High Precision Entry

  • A/C crosses holding fix and turns left to heading of 168 deg

  • A/C flies 168 deg for 41 sec

  • A/C rolls into a left standard rate turn and rolls out on a heading of 315 deg

  • A/C flies head 315 for 4 sec

  • A/C turns right to heading of 012 and tracks holding radial for required one-minute inbound time to the holding fix

  • A/C flight track smoothly blends into ground track of the “Holding Pattern Solution”

  • Total entry time is 204 seconds

  • Pilot workload considerably reduced

Hybrid Parallel/Teardrop Entry into the Holding Pattern

• Aircraft heading to holding fix is 205 deg

• High Precision Entry

  • A/C crosses holding fix and turns left to heading of 027 deg

  • A/C flies 027 deg for 18 seconds

  • A/C turns right to heading of 012 and intercepts the holding radial with a 60-second inbound time

  • Total entry time is 253 seconds

  • Pilot workload considerably reduced

What Else Has Been Implemented in V3.0

• Hold Page

• Slightly different dialog box for entering • Inbound Course
• Holding Radial
• Bearing to Fix

• Altitude box added
• Defaultinboundlegtimeisnowbasedonaltitude

• Atandbelow14000MSL-60seconds • Above14000MSL-90seconds

What Else Has Been Implemented in V3.0 (Cont.)

• Answer Page

• Has “Entry Pattern” Button
• HPEgroundtrackofentryisshowninmagenta
• HPSgroundTrackisshowningrey
• Windvectorshownbybluearrowheadonheadingindicator • ButtonoptionforHPEorFAAentrygroundtrack

• HPEgroundtrackwillanimatejustasin“HoldPattern”

  • Hit“NowButton”whenoverthefix

  • Whenoninboundlegbacktotheholdingfix“NextTurntoHeadingwillbeoutbound heading for HPS

  • WhenA/CreturnstofixtheAPPwillautomaticallymoveto“HoldPattern”andstart animating

    • FAAgroundtrackshowninmagentadots

    • Doesnotanimate-GivesUseranIdeahowPilotWorkloadincreaseswhenwindspeed increases while attempting to get established on the holding radial

What Else Has Been Implemented in V3.0 (Cont.)

• Protractor Button Shows Airspace Dimensions

• In addition to HPS dimensions, it also shows “Holding Pattern Primary Protected Airspace”

• “Bounding Box” described in FAA 8360.3F Figure 16-6-1 shown in red lines • PatternTemplatefitsinsideBoundingBox
• Shows“PatternNumber”ofTemplate

Summary of V3.0 HPE/HPS/EFC Capability

• HPE/HPS/EFCAdvancedTechnologyMethod

  • Holding Pattern Protected Airspace can be minimized using HPE/HPS/EFC

    • Primary Protected Airspace determined by overlaying bounding boxes during 7 different entries to holding pattern

      • Direct and Parallel from 290 heading to holding fix

      • Direct and Teardrop from 110 heading to holding fix

      • Parallel and teardrop entry from 180 heading to holding fix

      • Entry along holding radial

    • Same method used to develop holding pattern Primary Protected Airspace for FAA

  • Only limitation on re-intercepting holding radial is wind speed ratio less than 1

    • Should satisfy both GA and Commercial aircraft flying the hold

  • No need to identify abeam point: Reduces Pilot Workload during the hold

  • Exact DR(Dead Reckoning) Turn Points used in place of Design Turn Point and estimated RNAV Turn Points

• Aircraft intercepts holding radial at the same ATD independent of TAS • EFC capability incorporated in HPS

• Final circuit outbound time and outbound heading provided to allow aircraft to arrive back at the holding fix at the specified EFC time

• HPEmethodologyallowsaircrafttocrosstheholdingfixwithpredeterminedoutboundheading and time which allows aircraft to intercept holding radial at the point which satisfies ATD or required inbound time with minimum error

• Entry ground track smoothly blends into the HPS ground track when error is zero
• When error in non-zero, intercept point will occur slightly outside target intercept point

For Questions or Comments on V3.0

• Contact
• Les Glatt, PhD, ATP
• Email: lgtech@roadrunner.com • Phone: (818) 414-6890