Patent Document

BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   Embodiments of the present invention generally relate to devices used by pilots to determine entry into a holding pattern. 
   2. Description of the Related Art 
   Both commercial and general aviation flying depend on weather and flight rules defined by Federal Aviation Administration (FAA). If the weather is good and the flight is below 18,000 feet the FAA may permit aircraft to fly using simple visual flight rules (VFR). Under VFR a pilot may only operate at minimum prescribed distances from clouds and defined visibility. If the visibility is restricted or the airplane must fly in the clouds or if the flight is above 18,000 feet, more rigorous instrument flight rules (IFR) must be followed. Under IFR the pilot flies by reference to the aircraft instruments and follows special, IFR navigational charts. Most IFR flights must be coordinated by aircraft traffic control (ATC). Under most conditions, the pilot must be in two-way radio communication with ATC. As in the case of ground traffic, there can be heavy traffic in the air, particularly near airports. 
   While ground traffic can and often does come to full stop, aircraft, other than helicopters or balloons, cannot stop. Therefore, in lieu of coming to a complete stop in the air, ATC may instruct the pilot to fly a prescribed oval or race track shaped shape pattern called hold. The hold is generally defined in location and orientation by reference to a local navigational transmitter. The FAA also prescribes the entry method in which the pilot enters the hold. The entry method depends on a direction the airplane approaches the hold and the orientation of the hold. There are three standard entry methods. These are direct entry, parallel entry, and teardrop entry. Once established in the hold, the pilot will make all turns to the right, unless otherwise instructed by ATC or indicated by IFR navigational charts. When all the turns are made to the right, the holding pattern is called a right holding pattern or standard hold. When all turns are made to the left, the holding pattern is called a left holding pattern or nonstandard hold. In order to determine the correct entry method into the hold, the pilot must calculate an angle between the orientation of the hold and the heading of the airplane. The pilot must then take into account whether the holding pattern is a right or left holding pattern. Unfortunately, the entry method for entering the hold can be difficult to compute and visualize especially under stress associated with operating an aircraft in an IFR environment. Often the pilot makes a mistake and uses the wrong entry method, sometimes with serious consequences. 
   There are, several devices available to help with the calculation of the entry method. Unfortunately, these devices are designed for use in the classroom and in training and are lacking in simplicity, speed, and complete information. Moreover, such devices are additional equipment to find in an already tight cockpit and are not easily attached to a pilot&#39;s knee-board. Moreover, such devices typically require two hands to operate and do not automatically provide an indication with north at the top, thus inducing the typical pilot to make a sketch of the holding pattern and entry method. Therefore, what is needed is an apparatus that will enable a pilot under the stress of instrument conditions to quickly determine and visualize a holding pattern orientation and the entry method for entering the holding pattern, that can be attached to a knee-board and can easily operated with one hand, while in flight. 
   SUMMARY OF THE INVENTION 
   One aspect of the present invention is an apparatus for determining and visualizing a holding pattern and a holding entry. The apparatus includes a base having top edge and adapted to be secured to a kneeboard and a disk having a first surface and a second surface distal the first surface. The disk may be imprinted on the disk first and second surfaces with degree indicia relative a center and including an indicia representing North. The apparatus further includes a first disk overlay, which is substantially transparent and imprinted with indicia including a right holding pattern, a holding fix, a holding radial, a teardrop initial heading, a teardrop entry path, a parallel entry path, a parallel final intercept course, a teardrop entry region, a parallel entry region, and a direct entry region. The disk overlay is rotatably affixed to the disk first surface at about the center of the disk. The disk overlay is adapted for easy rotation by one hand, about the holding fix indicia, wherein the disk overlay may be rotated to align the holding radial with a predetermined degree on the disk. The apparatus further includes a second disk overlay. Which is substantially transparent and imprinted with indicia including a left holding pattern, a holding fix, a holding radial, a teardrop initial heading, a teardrop entry path, a parallel entry path, a parallel final intercept course, a teardrop entry region, a parallel entry region, and a direct entry region. The second disk overlay rotatably affixed to the disk second surface at about the center of the disk, and distal the first disk overlay. The disk overlay is rotatable about the holding fix, wherein the disk overlay may be rotated to align the holding radial with a predetermined degree on the disk second surface. The apparatus further includes two connecting brackets. The connecting brackets are pivotally attached at one end to the base, and pivotally attached at another end to the disk. The axis of pivot of the disk about the connecting bracket is offset from the center of the disk. The disk may be easily pivoted by one hand, to dispose the disk first surface distal the base. The disk may also be easily pivoted by one hand to dispose the disk second surface distal the base. The degree indicia is disposed on the disk first surface with North proximate the top edge of the base when the disk first surface is distal the base and the degree indicia is disposed on the disk second surface with North proximate the top edge of the base when the disk second surface is distal the base. 
   One aspect of the present invention is an apparatus for determining and visualizing a holding pattern, the apparatus includes a base adapted to be secured to a surface, permitting operation of the apparatus by one hand. The apparatus further includes a disk having a first surface and a second surface distal the first surface, and a compass rose imprinted on the disk first and disk second surface. The apparatus further includes one or more disk overlays, which are substantially transparent and imprinted with indicia representing a holding pattern including a holding fix. The one or more disk overlays are rotatably affixed to the disk surface at about the center of the compass rose and are adapted for easy rotation by one hand, about the holding fix indicia. The apparatus further includes one or more connecting brackets pivotally attached at one end to the base, and pivotally attached at another end to the disk, the axis of pivot of the disk about the connecting bracket being offset from the center of the disk, permitting the disk to be easily pivoted by one hand. 
   One aspect of the present invention is an apparatus for determining and visualizing a holding pattern, the apparatus includes a base adapted to be secured to a surface, permitting operation of the apparatus by one hand. The apparatus further includes a disk having a first surface and a second surface distal the first surface, a compass rose imprinted on the disk first surface and a compass rose imprinted on the disk second surface. The apparatus further includes one or more disk overlays, which are substantially transparent and imprinted with indicia representing a holding pattern including a holding fix. The one or more disk overlays are rotatably affixed to the disk surface at about the center of the compass rose and are adapted for easy rotation by one hand. The apparatus further includes one or more connecting brackets pivotally attached at one end to the base, and pivotally attached at another end to the disk, permitting the disk to be easily pivoted by one hand. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings. 
     It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the present invention may admit to other equally effective embodiments. 
       FIG. 1   a  is a plan view, diagram of a standard (right) holding pattern in accordance with aspects of FAA procedures. 
       FIG. 1   b  is a plan view, diagram of a nonstandard (left) holding pattern in accordance with aspects of FAA procedures. 
       FIG. 2   a  is a plan view, diagram of an aircraft making a direct entry to a standard holding pattern in accordance with aspects of FAA procedures. 
       FIG. 2   b  is a plan view, diagram of an aircraft making a direct entry to a left holding pattern in accordance with aspects of FAA procedures. 
       FIG. 3   a  is a plan view, diagram of an aircraft making a parallel entry to a right holding pattern in accordance with aspects of FAA procedures. 
       FIG. 3   b  is a plan view, diagram of an aircraft making a parallel entry to a nonstandard holding pattern in accordance with aspects of FAA procedures. 
       FIG. 4   a  is a plan view, diagram of an aircraft making a teardrop entry to a standard holding pattern in accordance with aspects of FM procedures. 
       FIG. 4   b  is a plan view, diagram of an aircraft making a teardrop entry to a left holding pattern in accordance with aspects of FAA procedures. 
       FIG. 5  is a front perspective view of one embodiment of a holding pattern aid in accordance with aspects of the invention. 
       FIG. 6  is an exploded front perspective view of the holding pattern aid in accordance with aspects of the invention. 
       FIG. 7  is a layout of the printed markings on a right overlay of  FIG. 6  in accordance with aspects of the invention. 
       FIG. 8  is a top plan view of the holding pattern aid in accordance with aspects of the invention. 
       FIG. 9  is a layout of the printed markings on a left overlay of  FIG. 6  in accordance with aspects of the invention. 
       FIG. 10  is a top plan view of the holding pattern aid in accordance with aspects of the invention. 
       FIG. 11  is a front perspective view of the holding pattern aid disposed on a kneeboard. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   In the following description, numerous specific details are set forth to provide a more thorough understanding of the present invention. However, it will be apparent to one of skill in the art that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the present invention. 
   In order to more clearly understand the use of the invention,  FIGS. 1-4  are presented to illustrate the problem a pilot has in visualizing a holding pattern and in determining an entry procedure for the holding pattern while flying in instrument conditions.  FIGS. 5-14  are presented to illustrate the invention and the use of the invention as an aid to a pilot in the cockpit while flying in instrument conditions to visualize the assigned holding pattern and to determine the correct entry procedure. 
     FIG. 1   a  is a plan view, diagram of a standard (right) holding pattern  100  in accordance with aspects of FAA procedures. A holding fix F on a radial  110  is assigned by Air Traffic Control (ATC). Holding fix F may be defined by the intersection of radial  110  with another radial or by a predetermined distance from the source of radial  110 . Right holding path  120  includes the holding fix F, an inbound course  124 , and an outbound course  122 . Inbound course  124  is coincident with radial  110  and flown in the direction of holding fix F. Outbound course  122  is parallel with radial  110  but flown away from fix F, in a direction opposite inbound course  124 . Inbound course  124  and outbound course  122  are connected by a standard rate turn  126 . It will be appreciated by practitioners of the art of instrument flying that in a standard holding pattern  120 , all turns are made to the right while following the course of the holding path  120 . 
   In practice, an aircraft once established in right holding path  120  begins a standard rate right turn upon intercepting holding fix F. A standard rate turn is a turn that takes one minute to complete 180 degrees or a turn of rate 3 degrees per minute. After completing a 180-degree standard rate right turn  126 , the aircraft flies outbound from the fix F along outbound course  122  for about one minute. After about one minute flying along outbound course  122 , the aircraft again makes a standard rate right turn  126  to the right for about one minute. After completing turn  126 , the aircraft flies inbound along radial  110  towards holding fix F. In the absence of wind, the aircraft will arrive at holding fix after one minute and begin another standard rate turn to make another trip around the holding path  120 . This will continue until the aircraft receives instructions from ATC to leave the hold. The standard rate turns  126  and outbound course  122  may be adjusted to accommodate wind effects and to ideally place the aircraft at the holding fix at the end of one minute on the inbound course  124 . 
   Aircraft approaching holding fix F are required by FAA rules enter right holding path  120  according to prescribed procedures. For this purpose, airspace around holding fix F may be divided into three sectors, sectors A, B, and C by an imaginary line  112 . Imaginary line  112  forms an acute angle DFE of about 70 degrees with radial  110 . Angle DFE bounds sector A. An aircraft  101  approaching holding fix F from the area of sector A is required by FAA procedures to make a teardrop entry (described below) when entering holding path  120 . Imaginary line  112  also forms an oblique angle EFG of about 110 degrees with radial E. Sector B is bounded by angle EFG. An aircraft  102  approaching holding fix F from the area of sector B is required by FAA procedures to make a parallel entry (described below) when entering holding path  120 . Imaginary line  112  forms an angle DFG of about 180 degrees. Angle DFG bounds sector C. Sector C is the area distal imaginary line  112  from sectors A and B. An aircraft  103  approaching holding fix F from the area of sector C is required by FAA procedures to make a direct entry (described below) when entering holding path  120 . 
     FIG. 1   b  is a plan view, diagram of a nonstandard (left) holding pattern  100 ′ in accordance with aspects of FAA procedures. In the nonstandard holding pattern  100 ′ all turns are made to the left. Consequently, left holding pattern  100 ′ is a mirror image of right holding pattern  100 . Nonstandard holding patterns  110 ′ are established to avoid areas of heavy air traffic, obstructions, and terrain. A left holding path  120 ′ includes outbound course  122 ′ and inbound course  124 . It will be appreciated by practitioners of the art of instrument flying that inbound course  124  and outbound course  122 ′ are connected by standard rate turns  126 ′ that are made to the left. In the nonstandard holding pattern, imaginary line  112 ′ forms acute angle D′FE of about 70 degrees with radial  110 . Sector A is bounded by angle D′EF. Imaginary line  112 ′ forms oblique angle EFG′ of about 110 degrees with radial  110 . Sector B is bounded by angle EFG′. Imaginary line  112 ′. Imaginary line  112  ‘forms an angle D′FG’ of about 180 degrees. Angle D′FG′ bounds sector C. Sector C is the area distal imaginary line  112 ′ from sectors A and B. 
     FIG. 2   a  is a plan view, diagram of an aircraft  103  making a direct entry to a standard holding pattern  100  in accordance with aspects of FAA procedures. When the aircraft  103  arrives at the holding fix F after approaching from anywhere in sector C, the aircraft  103  begins a standard rate turn  126  to the right. The aircraft  103  continues the standard rate turn to the right until established on the outbound course  122 . From that point, the aircraft may continue to follow the right holding path  120  as described above. 
     FIG. 2   b  is a plan view, diagram of an aircraft  103  making a direct entry to a left holding pattern  100 ′ in accordance with aspects of FAA procedures. When the aircraft  103  arrives at the holding fix F after approaching from anywhere in sector C, the aircraft  103  begins a standard rate turn  126 ′ to the left. The aircraft  103  continues the standard rate turn to the left until established on the outbound course  122 ′. From that point, the aircraft may continue to follow the left holding path  120 ′ as described above. 
     FIG. 3   a  is a plan view, diagram of an aircraft  102  making a parallel entry to a right holding pattern  100  in accordance with aspects of FAA procedures. When the aircraft  102  arrives at the holding fix F after approaching from anywhere in sector B, the aircraft  102  turns to fly a parallel path  324 . Parallel path  324  is parallel to inbound course  124  in a direction opposite to inbound course  124 . The aircraft  102  flies the parallel path  324  for about 1 minute then begins a standard rate turn  326  to the left until established on the inbound course  124 . From that point, the aircraft may continue to follow the right holding path  120  as described above. 
     FIG. 3   b  is a plan view, diagram of an aircraft  102  making a parallel entry to a nonstandard holding pattern  100 ′ in accordance with aspects of FAA procedures. When the aircraft  102  arrives at the holding fix F after approaching from anywhere in sector B, the aircraft  102  turns to fly the parallel path  324 . The aircraft  102  flies the parallel path  324  for about 1 minute then begins a standard rate turn  326 ′ to the right until established on the inbound course  124 . From that point, the aircraft may continue to follow the left holding path  120 ′ as described above. 
     FIG. 4   a  is a plan view, diagram of an aircraft  101  making a teardrop entry to a standard holding pattern  100  in accordance with aspects of FAA procedures. When the aircraft  101  arrives at the holding fix F after approaching from anywhere in sector A, the aircraft  101  turns to fly outbound from holding fix F on a teardrop path  424 . Teardrop path  424  is prescribed by the FAA to be at an angle H of about 30 degrees to the left of inbound course  124 . The aircraft  101  flies the teardrop path  424  for about 1 minute then begins a standard rate turn  426  to the right until established on the inbound course  124 . From that point, the aircraft may continue to follow the right holding path  120  as described above. 
     FIG. 4   b  is a plan view, diagram of an aircraft  101  making a teardrop entry to a left holding pattern  100 ′ in accordance with aspects of FAA procedures. When the aircraft  101  arrives at the holding fix F after approaching from anywhere in sector A, the aircraft  101  turns to fly outbound from holding fix F on a teardrop path  424 ′. Teardrop path  424 ′ is prescribed by the FAA to be at an angle H of about 30 degrees to the right of inbound course  124 . The aircraft  101  flies the teardrop path  424 ′ for about 1 minute then begins a standard rate turn  426 ′ to the left until established on the inbound course  124 . From that point, the aircraft may continue to follow the left holding path  120 ′ as described above. 
     FIG. 5  is a front perspective view of one embodiment of a holding pattern aid  500  in accordance with aspects of the invention.  FIG. 6  is an exploded front perspective view of the holding pattern aid  500  in accordance with aspects of the invention. Holding pattern aid  500  includes a base  502  connected to a holding pattern display  520  by one or more connecting brackets  514 . Base  502  includes one or more tabs  512  adapted to pivotally engage brackets  514  and adapted to pivot through a predetermined angle φ. Bracket  514  is illustrated as bent in a loop to secure bracket  514  to tab  512 . Alternatively, bracket  514  may be secured to tab  512  by rivet, screw, grommet, or other like fastener adapted to permit pivoting of bracket  514  through predetermined angle φ. Base  520  further includes aperture  504  adapted to accept a lanyard (illustrated below) for securing holding pattern aid  500  to advantage. Base  502  further includes a left indicia  508  and a right indicia  510  for alerting the user that holding pattern aid  500  is configured to illustrate a standard (right) holding pattern or a nonstandard (left) holding pattern. Right indicia  510  may include the word “RIGHT” for example. Left indicia  508  may include the word “LEFT” for example. Other characters may be used to advantage, for example “R” and “L”. Base  502  further includes kneeboard aperture  506  for engaging a pilot kneeboard clamp (illustrated below). 
   Holding pattern display  520  includes a disk  522 , a right overlay  530 , a left overlay  532 , and an overlay axis  528 . A face  531  of disk  522  may be imprinted with degree indicia representing a compass rose. A face  533  (illustrated below in  FIG. 10 ), distal face  531  of disk  522  may be imprinted with degree indicia representing a compass rose.  FIG. 5 , for example illustrates face  531  imprinted with a compass rose including degree indicia every 5 degrees and numeric degree indicia every 20 degrees as well as indicia representing North “N”, South “S”, East “E”, and West “W”. “N”, is oriented such that the “N” is proximate an upper edge  509  when face  531  is the visible face. Face  533  may be imprinted with the same compass rose in the same orientation as face  531 , i.e. with “N” proximate the upper edge  509  when face  533  is the visible face. 
   Right overlay  530  may be imprinted with a representation of a right holding pattern (described below). Left overlay  532  may be imprinted with a representation of a left holding pattern (described below). Left overlay  532  may be a mirror image of right overlay  530 . Overlay axis  528  is illustrated in  FIG. 6  as including a screw  512 , a nut  513  and an aperture  511  and  511 ′. Screw  512  and nut  513  may rotationally secure overlays  530  and  532  to disk  522  by engaging apertures  511  and  511 ′ while permitting overlay  530  free rotation about overlay axis  528 . Alternatively, overlays  530  and  532  may be rotationally affixed to disk  522  by rivets, grommets, or other fasteners adapted to permit free rotation of overlays  530  and  532  about overlay axis  528 . Aperture  516  permits holding pattern display  520  to lay flat on base  502  without interference with nut  513  or screw  512 . 
   Disk  522  may include one or more cavities  526  for pivotally accepting brackets  514 .  FIG. 5  illustrates brackets  514  bent at right angles for engaging a cavity  526  in disk  522  and permitting free pivoting of disk  522  through a predetermined angle Θ. However, bracket  514 ′ may also be a substantially flat material, as illustrated in  FIG. 6 . The bracket  514 ′ may be secured by fastening means, such as screws, pins, nails, dowels, detents, or rivets for example, adapted for pivotally engaging bracket  514  and permitting free pivoting of disk  522  through a predetermined angle Θ. Alternatively, a fastening means such as a post may be affixed to disk  522  for pivotally engaging bracket  514  and permitting free pivoting of disk  522  through a predetermined angle Θ. 
   A centerline  527  is illustrated bisecting disk  522  along a line from W to E, through overlay axis  528 , on disk  522 . The centerline  527  is for illustrative purposes and is not part of the invention or markings printed on face of the disk  522  or the overlays  530 ,  532 . An offset between the centerline  527  and pivot cavity  526  may be sized to permit disk  522  to cover left indicia  508  when bracket  514  is parallel with base  502 , while permitting right indicia  510  to remain visible to the user when overlay  530  is visible. The offset between centerline  527  and pivot cavity  526  also may be sized to permit disk  522  to cover right indicia  508  while permitting left indicia  510  to remain visible to the user when overlay  532  is visible. 
     FIG. 7  is a layout of the printed markings on the right overlay  530  in accordance with aspects of the invention.  FIG. 9  is a layout of the printed markings on the left overlay  532  in accordance with aspects of the invention.  FIG. 7  shows printed markings that are a mirror image the printed markings of  FIG. 9 . Overlays  530 , 532  may be substantially transparent to permit the indicia on disk faces  531 , 533  to be visible to the user. Right overlay  530  is a diagrammatic representation of a right holding pattern  100 . Right overlay  530  includes a radial  710  representing radial  110 , an imaginary line  712  representing imaginary line  112 , a right holding path  720  representing right holding path  120 , and a holding fix at aperture  511 ′ representing holding fix F. Right overlay  530  further includes a teardrop entry path  724  representing teardrop path  424 , and a parallel entry path  726  representing parallel path  324 . Right overlay  530  further includes a teardrop entry course indicator  716 , which indicates a course to turn to upon crossing the holding fix F for executing a teardrop entry procedure. Right overlay  530  further includes a parallel intercept indicator  718 , which indicates a final course to turn to for completing the teardrop entry procedure and intercepting the inbound course  124 . Right overlay  530  further includes a DME Arc indicator  714  which may be useful for flying a DME Arc procedure. The DME Arc indicator  714  may also be useful for indicating when the pilot is abeam the holding fix and may begin timing the outbound leg of the hold. Sector A, sector B, and sector C may be color tinted transparencies according to a color scheme selected to advantage for ease of recognition during flight. Right holding path  720 , radial  710 , imaginary line  712 , teardrop entry path  724 , parallel entry path  726 , teardrop entry course indicator,  716  parallel intercept indicator  718  and DME Arc indicator  714  may be color coded according to a color scheme to advantage, to enhance quick and easy recognition. 
   Left overlay  532  is a diagrammatic representation of a left holding pattern  100 . Left overlay  532  includes a radial  710  representing radial  110 , an imaginary line  712 ′ representing imaginary line  112 ′, a left holding path  720 ′ representing left holding path  120 ′, and a holding fix at aperture  511 ′ representing holding fix F. Left overlay  532  further includes a teardrop entry path  724 ′ representing teardrop path  424 ′, and a parallel entry path  726  representing parallel path  324 . Left overlay  532  further includes a teardrop entry course indicator  716 ′, which indicates a course to turn to upon crossing the holding fix F for executing a teardrop entry procedure. Left overlay  532  further includes a parallel intercept indicator  718 ′, which indicates a final course to turn to for completing the teardrop entry procedure and intercepting the inbound course  124 . Left overlay  532  further includes a DME Arc indicator  714 ′ which may be useful for flying a DME Arc procedure. Sector A, sector B, and sector C may be color tinted transparencies according to a color scheme selected to advantage for ease of recognition during flight. Left holding path  720 ′, radial  710 , imaginary line  712 ′, teardrop entry path  724 ′, parallel entry path  726 ′, teardrop entry course indicator,  716 ′ parallel intercept indicator  718 ′, and DME Arc indicator  714 ′ may be color coded according to a color scheme to advantage, to enhance quick and easy recognition. 
     FIG. 8  is a top plan view of the holding pattern aid  500  in accordance with aspects of the invention. Holding pattern display  520  is illustrated disposed with the right overlay  530  and face  531  visible to the user. Right indicia  510  “RIGHT” is also visible to the user.  FIG. 8  also illustrates flat brackets  514 ′. 
     FIG. 10  is a top plan view of the holding pattern aid  500  in accordance with aspects of the invention. Holding pattern display  520  is illustrated disposed with the left overlay  532  and face  533  visible to the user. Left indicia  508  “LEFT” is also visible to the user. 
     FIG. 11  is a front perspective view of the holding pattern aid  500  disposed on a kneeboard. The kneeboard is not a part of the invention. The typical kneeboard includes a spring-biased clip  1002  for securing notepaper. The clip  1002  typically has two or more cylindrical pads  1006  mounted proximate corners for increasing friction between the clip  1002  and notepaper. Aperture  506  may be sized to advantage for engaging cylindrical pad  1006  to constrain holding pattern aid  500  in position and prevent slippage. 
   In operation, holding pattern aid  500  may be secured to any fixed surface, such as a kneeboard for example. The aperture may engage the clip  1002  and/or the cylindrical pads  1006 , rigidly fixing holding pattern aid  500  relative the kneeboard. A lanyard may be secured to aperture  504  to enable the pilot to quickly locate a loose holding pattern aid  500  or to prevent the aid  500  from becoming lost should it accidentally be released from the kneeboard clip. The holding pattern display  520  may be lifted up by pivoting the brackets  514  about tabs  512 , and flipped over. Thus right overlay  530  or left overlay  532  may be placed face up for view by the pilot. The offset between the bracket  514  engagement points  526  and the centerline results in either the right indicia  510  or the left indicia  508  informing the pilot of the orientation of the holding pattern display  520 . Should the pilot wish to change from a left overlay  532  to a right overlay  530 , for example, the pilot simply lifts up the holding pattern display  520  and flips it over and sets it back flat on base  502 . This motion may be quickly accomplished with one hand or even the flick of one finger since the base is secured to the kneeboard. The pilot may then rotate the desired overlay, such as the right overlay  532  for example, to place the radial  710  coincident with the radial assigned by ATC. Such rotation may be accomplished by one hand since the holding pattern aid  500  is rigidly fixed. The right holding pattern  720  is displayed relative the compass rose on face  531 . The pilot may then quickly determine at a glance the appropriate entry procedure based on the aircraft bearing to the fix F and the display  520 . If the pilot executes a teardrop entry, the teardrop entry course indicator  716  tells the pilot instantly what bearing to turn to upon crossing the holding fix F. If the pilot executes a parallel entry, the parallel intercept indicator  718  tells the pilot instantly what the final bearing will be for intercepting the inbound course upon completing the parallel intercept procedure. The DME Arc indicator  714  may be used for indicating when the pilot may begin timing the outbound leg of the hold abeam the holding fix F. The DME Arc indicator  714  may also be useful by pilots skilled in the arts of flying instruments for flying a DME Arc procedure. The radial  710  may be used for instantly determining bearing reciprocals. In this example a right overlay  530  was used. Similarly the left overlay  532  may also be disposed with the flick of a finger, and then rotated into a predetermined position. The display  520  may then be used to visualize the left hold and determine the appropriate entry procedure. 
   While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Technology Category: g