6 Special. 6.1 Joining a visual circuit (Psion v). 6.1.1 Introduction. Joining a visual circuit is potentially one of the most hazardous phases of any flight as no direct control of aircraft is realistically possible; hence the term visual circuit. Visual circuit is an Acmenav facility that is designed to assist in the task of deciding which leg of the visual circuit to join and make it easier to discern the airfield approach quadrant. 6.1.2 Operation. Selecting the visual circuit option from the special section of the main menu (or using the hot key combination Psion v), causes a dialogue box to be displayed that requires you to enter the runway QDM, your joining heading and select the circuit direction (left or right hand). Pressing whilst this dialogue box is on display returns you to the main Acmenav menu Once this input dialogue box has been completed by pressing , a small airfield circuit diagram will be drawn. The black square in the centre of the screen is divided up into four imaginary, equally sized, little squares that indicate from which quadrant relative to the runway you are approaching the airfield from. It should be fairly obvious from this diagram which leg of the circuit it will be most convenient to join, however, if further clarification is required, press the key and select which of the six standard joins you would like demonstrated. The selected join will then be demonstrated on the screen for you. You can continue to select all the different types of join if you wish by repeated selections from the menu. Whether you have had any joins demonstrated or not, the only way to exit this display is to select the exit option from the special section of the circuit joining menu (or use the hot key combination Psion x), whereupon you will be returned to the input dialogue box. 6.2 Keeping track of UK weather minima (Psion w). 6.2.1 Introduction. Keeping track of the VMC requirements for UK pilots is a real pain. The VMC criteria that define minimum weather requirements for VFR flight vary not only with airspace classification but also ratings held, passengers carried, intended height band, and sometimes IAS. Obviously this particular option is of unique use to UK pilots as the UK VMC criteria are different to those elsewhere in the world. 6.2.2 Operation. On selecting the visual circuit option from the main menu (or using the hot key combination Psion w), you will be presented with a dialogue box that requires you to select whether you have an IMC rating or not. Pressing whilst this first input dialogue box is on display returns you to the main Acmenav menu. Once this first input dialogue box has been completed by pressing , the second and main input dialogue box will be presented that requires you to select the classification of the airspace you intend flying in, the height banding, the IAS banding, and whether you are carrying passengers or not. Pressing whilst this second input dialogue box is on display returns you to the rating selection dialogue box. It should be noted that IAS is only relevant at or below 3000 feet AMSL whilst flying in F, G, or D (not schedule 8 notified) airspace. Do not be concerned if you cannot remember these provisos, Acmenav is written in such a way that if you are not flying in one of the affected airspace classes, the IAS selection is ignored. Once the main input dialogue box has been completed by pressing , the weather conditions that must be required to maintain VMC are displayed. If you press whilst the weather minima dialogue box is on display, you will be returned to the flight details (the second main) input dialogue box. 6.3 Frequency pairing (Psion s). 6.3.1 Introduction. It isn't often that you will need to pair TACAN channels with DME frequencies, or ILS localiser frequencies with their glideslope frequencies. However, when you do need these functions, you will find Acmenav's pairing facilities quick, easy to use, and accurate. Full facilities are included to pair (in both cases in either direction) TACAN channels with DME frequencies, and ILS localiser frequencies with glideslope frequencies. On selecting the Freq' pair option from the special section of the main menu (or using the hot key combination Psion s), you will be presented with another menu called the frequency pairing menu. Operation of the frequency pairing menu is fairly straight forward. With the exception of the special section, each of the other menu sections provides access to the pairing facilities of either TACAN/DME pairing or ILS pairing. 6.3.2 Pairing a TACAN channel to a DME frequency (Psion d). To pair a TACAN channel to its equivalent DME frequency, select the TACAN-DME option from the TACAN/DME section of the frequency pairing menu. A dialogue box will then be presented that requires you to enter the TACAN channel number and select the channel designator (either X or Y). Pressing whilst this input dialogue box is on display returns you to the frequency pairing menu. Upon completion of the input dialogue box by pressing , and providing that the entered channel is a valid one, the TACAN channel will be paired and its equivalent DME frequency displayed. Pressing whilst this dialogue box is on display returns you to the TACAN channel input dialogue box. 6.3.3 Pairing a DME frequency to a TACAN channel (Psion t). To pair a DME frequency to its TACAN channel, select the DME-TACAN option from the TACAN/DME section of the frequency pairing menu. A dialogue box will then be presented that requires you to select the DME frequency. Pressing whilst this input dialogue box is on display returns you to the frequency pairing menu. Upon completion of the input dialogue box by pressing , the DME frequency will be paired and its equivalent TACAN channel displayed. Pressing whilst this dialogue box is on display returns you to the DME frequency input dialogue box. 6.3.4 Pairing localiser to glideslope frequencies (Psion g). To pair an ILS localiser frequency to its glideslope frequency, select the Localiser-glideslope option from the ILS section of the frequency pairing menu. A dialogue box will be displayed that requires you to enter the localiser frequency. Pressing whilst this dialogue box is on display returns you to the frequency pairing menu. Upon completion of the input dialogue box, the localiser frequency will be paired and its equivalent glideslope frequency displayed. Pressing whilst this dialogue box is on display returns you to the localiser frequency input dialogue box. 6.3.5 Pairing glideslope to localiser frequencies (Psion l). To pair an ILS glideslope frequency to its localiser frequency, select the Glideslope-localiser option from the ILS section of the frequency pairing menu. A dialogue box will be displayed that requires you to enter the glideslope frequency. Pressing whilst this dialogue box is on display returns you to the frequency pairing menu. Upon completion of the input dialogue box, the glideslope frequency will be paired and its equivalent localiser frequency displayed. Pressing whilst this dialogue box is on display returns you to the glideslope frequency input dialogue box. 6.4 Performing centre of gravity calculations (Psion q). 6.4.1 Introduction. Acmenav contains facilities for the quick and easy calculation of the centre of gravity position in aircraft. 6.4.2 Calculating the centre of gravity. After selecting the Quick cg option from the special section of the main menu (or using the hot key combination Psion g), an input dialogue box will be presented that is used for the input of all weights and lever arms during a centre of gravity calculation. Each station is treated in turn by entering its weight and lever arm into the dialogue box. Once the details of a particular station have been entered, pressing the "m" key allows you to enter the details of the next station (it will be noted that station number counter will increment by one). Pressing the key whilst this input dialogue box is on display returns you to the main Acmenav menu. Once all the station details have been entered, pressing the "s" key will produce a solution to the centre of gravity details that have been entered. Pressing the key whilst the solution dialogue box is on display returns you to the input dialogue box. 6.4.3 Fuel volume to weight conversions. It will be noticed that the input dialogue box gives access to the fuel volume to weight converter. If, whilst performing a centre of gravity calculation, you wish to calculate how much a specific volume of fuel weighs, and then wish to enter this weight into the centre of gravity calculation, press the "f" key and you will be taken to the fuel conversion facility (see section 3.6 of this manual for details of the operation of this facility). The only difference between normal operation of the fuel conversion facility and operation when it is called from the centre of gravity calculator is that you will be returned to the centre of gravity calculation with the highlighted fuel weight automatically inserted into the weight section of the current station details on exit. You can make the jump into the fuel conversion facility whenever you wish to without concerning yourself that the centre of gravity calculation is going to be disturbed. On return, the calculation will be exactly where you left it. 6.4.4 Stations and the centre of gravity datum. All stations aft of the centre of gravity datum should be entered as positive values whilst stations forward of the centre of gravity datum should be entered as negative values. Similarly, answers that are displayed as negative values indicate a centre of gravity position forward of the datum, whilst positive answers indicate a centre of gravity position aft of the datum. 6.5 Converting a navaid's ident into Morse code (Psion i). 6.5.1 Introduction. Although all navaids in the database automatically have their idents displayed in Morse code, there may be occasions when it is useful to convert a series of letters into Morse code. Acmenav has a facility to do just this. 6.5.2 Operation. On selecting the indent' option from the special section of the main menu (or using the hot key combination Psion i), you will be presented with a dialogue box that requires you to enter the ident' you wish to have converted into a Morse string (up to 3 letters). Pressing whilst the input dialogue box is on display returns you to the Acmenav main menu. Upon completing the input dialogue box by pressing , the entered letters will be converted into Morse code that will be displayed as a series of dots and dashes. Pressing whilst this answer dialogue is on display returns you to the Acmenav main menu.