Hold Entry Page Reference

Related documents

• Page Reference
• Navigation System Reference
• SVG Drawing Module Reference

Table of Contents

• Introduction
  • Entry computation
• Exported identifiers
  • headingInputSvInfo
• Page state variables

Introduction

The Hold Entry page (page ID holdEnt) is an interactive holding pattern entry computer. It is defined in common/page/holdEntry.js. The page is independent of the aircraft, but it is optional: an app includes it by importing the file for its side effect (the C172, C182, PA28, Baron, Bonanza, Kodiak, and TBM apps do) and listing holdEnt in its nav layout (the aircraft apps list it under "Instrument Procedures"):

import './common/page/holdEntry.js';

The app needs to supply nothing else. The page has no saved state.

The user enters whether the hold uses left turns, the heading to the fix, and the outbound radial from the fix. The page computes the entry type and the instructions for the first turn after crossing the fix, and draws a heading-indicator diagram with the hold and entry superimposed. The user can also set the heading and radial by dragging the compass (heading) or the hold (radial) in the diagram.

Entry computation

The entry type is based on the angle from the heading to the radial, mirrored for left turns (AIM 5-3-8): a teardrop entry if the angle is between 0 and 70 degrees (exclusive) toward the hold side, a parallel entry if it is from 0 to 110 degrees toward the other side (inclusive), and a direct entry otherwise. The entry is blank if either heading or radial is not valid. The self-test Hold entry checks that the sectors cover 70, 110, and 180 headings for both turn directions. The page's output states are:

• teardrop
  The "After fix" text gives the turn to a heading 30 degrees off the radial, the turn after the leg time or distance to intercept the inbound course.
• parallel
  The "After fix" text gives the turn to the radial, and the turn after the leg time or distance to intercept the inbound course.
• direct
  The "After fix" text gives the turn to the radial in the direction of the hold.

The diagram redraws when the nav_darkMode state variable changes.

Exported identifiers

headingInputSvInfo

Syntax

import {headingInputSvInfo} from 'common/page/holdEntry.js';

The numericInput state variable info for a heading (format 3, 1–360, default 360, with a degree-sign label, not saved). The page uses it for holdEnt_heading and holdEnt_radial through SV.infoBasedOn().

Page state variables

All the state variables have the prefix holdEnt_.