ADVANCED FLIGHT

A number of modifications can be made to the standard flight sequence, for various purposes. This section details the advanced flight options.

Automated Flight

Most pilots prefer to use the automated flight sequence, which requires little effort. The procedure is simple. Close the door and activate the automatic power systems (APS). Ensure the dematerialisation lever is in the lower position. Enter coordinates as preferred. The journey will begin as the coordinates have been confirmed and sent into the NAGCS.

The rest of the flight sequence is fully automated. The pilot need take no further action. The ship will automatically power down and land at the calculated landing coordinate. The APS flight also controls the artron frequency of the power drive. The APC is not automatically controlled, pilots should manually activate this if so desired.

To completely automate the flight sequence the ship can provide the destination coordinates automatically. The pilot simply uses coordinate mode three, catalogue entries, or coordinate mode six, flight recorder. APS can of course be used with these coordinate modes, resulting in an almost effortless flight.

Advanced In-Flight Procedures

One useful procedure is late coordinate setting. Traditionally coordinates are set before dematerialisation, but with this mode the coordinates can be set after dematerialisation, provided that the corresponding UHL coordinate is entered before the TARDIS reaches the same UHL stage. Hence this flight mode works better with longer flights, as the pilot has more time to enter the full coordinate. If the TARDIS reaches a UHL stage before the pilot has entered its vcoordinate, the ship uses a null coordinate for its destination coordinate for that UHL level.

There exists a tricky maneuver to cross jump a time track within the space-time vortex. The guidance computer systems normally prevent such a maneuver, but by activating the vortex time tracker this safety measure is turned off. There are not many reasons to cross jump a time track. Indeed, rematerialising without first jumping back is extremely hazardous, and will result in time friction. It is recognised that cross jumping does have a few uses, such as escaping a timeship which is pursuing the TARDIS through the vortex.

The TARDIS itself has the ability to follow another timeship through the vortex, given that the ship being followed leaves a space-time trail. This maneuver is unlike many others, because it results in relying on the navigation systems on the craft which is being pursued! There is no UHL-navigation, the TARDIS simply follows the other craft through the vortex. Hence the entire flight is orchestrated by the guidance computer systems. Once the pursued craft rematerialises, the TARDIS will set a UHL level zero destination coordinate equal to the timeship, and then initiate a standard landing. Note that the time-streams for the two separate ships are running together, and henceforth landing the TARDIS a short time before the pursued timeship is impossible, as this period has become immutable past.

Sometimes a rematerialisation can become unstable for a variety of reasons. The stabilise materialise phase (SMP) switch attempts to buffer and stabilise the process.

A special feature available with Mark II models and above is the quick dematerialisation phase (QDP), which shortens the dematerialisation process to around three seconds, a similar feature to the QFM. The length of flight is not shortened by this process.

Quick Transference Jump

The quick transference jump (QTJ) allows the TARDIS to make an near instantaneous jump from one point in space to another. The maximum range is limited by the available power reserves, but is typically in the order of between 100 - 1000 km.

Ensure the ship is in full power mode, and begin the standard flight sequence as usual. Instead of setting many UHL coordinates, only one UHL coordinate may be set. Once this has been entered, activate the QTJ switch. As well as switching on the appropriate circuits, the dematerialisation lever will now no longer function as before. The lever should be lowered now, and the power drive lever should be lowered also, activating the full power mode. At this instance the TARDIS should perform a quick transference jump.

The QTF is similar in concept to the quick flight mode. There are some notable differences. The QTJ does not use the dematerialisation circuit, and the maneuver does not involve entering the space-time vortex, nor removing the ship occupants from the space-time continuum. Although QTJ flight is brief, and distance travelled is small, the flight is performed in the same way as the standard flight. The QTJ is also very quick, but it does consume a fair amount of electrical and artron power, and hence it is not a power saving option like the QFM.

Fast Return

For pilots who feel the need for speed there is the option of using the fast return switch. Fast return provides an effective telocity of around $0.5 \times 10^9 \mathrm{ys}^{-1}$. The ship's relocity is also vastly increased, due to shrinking of the space-time continuum. The are many cautions concerning this flight mode:

• this mode takes the TARDIS very deeply into the space-time vortex, where strange energies and creatures lurk.

• this mode must be turned off before the ship is taken back to the beginning of the universe! Once the switch is off, the TARDIS will navigate the ship to the correct space-time coordinate.

• fast return must only be used with the normal flight mode.

Apart from activating the fast return switch when appropriate, the rest of the flight sequence proceeds as normal.

Outerspace Travel

Although many pilots wish to visit planets throughout the universe, it is sometimes desirable to land in outerspace. This section details the changes to standard flight in order to begin and/or end a flight in outerspace. The key control is free float. The free float control allows the TARDIS to safely dematerialise from outerspace, and also to safely rematerialise into outerspace. Here outerspace is defined as a location in space which is not in a defined orbit around any planet or satellite. The location must have a very low force of gravitation.

Setting the coordinate can be a challenge. With free float, the error correcting protocols work differently, as the TARDIS no longer seeks the closest physical object with a significant mass. There are several approaches to selecting an outerspace coordinate; these are all detailed in Section .

Once the coordinates have been entered the TARDIS is ready for dematerialisation. In outerspace, as a safety measure, this will not happen until free float has been activated. The free float mode does not only inform the NAGCS that an outerspace flight is being programmed, but it also performs crucial stabilisation of the ship's outer-hull in outerspace, by neutralising some forms of drift and essentially creating an area of free space around the TARDIS, an area devoid of any physical interaction/forces.

The rest of the flight sequence proceeds as normal. If the destination is in outerspace, the free float mode must be activated prior to landing. Of course if the departure was also from outerspace, then the free float should still be activated.

If the ship has rematerialised in outerspace then the hovermode can be used to move the ship around, this is detailed in Section .

Hover Mode

The hovermode allows the TARDIS to hover mid-air in the presence of gravity. Basically the hovermode allows the TARDIS to become weight-less. It works by using the ship's space gravity drive (SGD). The SGD is responsible for motivating the TARDIS in real space, and is used exclusively by the hovermode. The SGD requires an artron feed, and hence hovermode requires the ship to be operating in normal power mode (NPM).

Hovermode works in two different ways. After rematerialisation into outerspace, hovermode can be used for outerspace maneouvers. The mode allows basic movement in three dimensions. After activating hovermode, levers 1D2-1D6 will change in their function, and become hover controls. The levers can be used to move the TARDIS through space. The first three levers control the direction of travel, whilst the last two set whether the TARDIS will move with constant speed, or with constant acceleration, and whether the movement shall be binary-like, that is, move or not move, or whether the rate of movement should be analogue, and related the distance the lever is pushed.

The second use of hovermode is used in combination with take-off or landing. Sometimes a local artron source can interfere with the ship's systems, and maneuvering the TARDIS away from the source can significantly reduce the level of artron energy interference. In this case, hovermode can be activated immediately prior to dematerialisation.

Dematerialisation does not have to follow hovering, although this is common. Using the hover thrust adjustment control, the ship can be raised vertically in the air. The movement control is strictly one dimensional: up or down. With the hoverlock switched on, the ship's weight is already counteracted, and hence with no thrust set on the thrust control, the ship will just hover, stationary. Moving the thrust lever up will accelerate the TARDIS upwards, but the ship will quickly slow to a stationary hover once the control is switched off. To descend, the hoverlock must be switched off. Without hoverlock, the ship's weight is not counteracted, and with no thrust either, the ship will begin to descend. The ship will crash into the ground without careful piloting with the hoverlock switched off.

Assuming hoverlock is on, the TARDIS can be dematerialised any time during hovermode. As a caution, note that hoverlock cannot be obtained whilst the TARDIS is in free-fall. Cautious pilots ensure the TARDIS has been hoverlocked before attempting dematerialisation; use the hover thrust control to slow down the TARDIS, and then activate hoverlock. Even if the TARDIS is still moving, hoverlock will halt the ship's movement, assuming the descent speed is low. The main point to note here is that the TARDIS cannot be dematerialised when it is plunging towards the ground as a result of a poor piloting during hovermode.

The TARDIS can also also rematerialise into hovermode. For this to happen, hovermode must be activated prior to landing. Free-float should normallu be switched off as the ship will be under the gravitational influence of its landing body. By setting a three dimensional UHL 0 coordinate the ship's $z$-coordinate may be specified above sea level at $(x,y)$. To rematerialise into hovermode simply ensure that hoverlock and hovermode are switched on. To rematerialise into geostationary orbit it is sufficient to set the UHL 0 locking protocol to geostationary orbit.

Time Loops