Formation/Recover

A Formation/Recover procedure is used to model the aircraft coordinating its flight with another STK's Aviator capability aircraft in the scenario. This procedure is only available to STK Vehicle sites that are also Aviator aircraft. While in formation, the aircraft's position, attitude, and velocity will be derived from the site aircraft.

The procedure is comprised of three segments - delay, cruise, and formation. The delay segment is optional and is performed at the end of the previous procedure. The cruise segment is performed after the delay segment and flies the aircraft to the formation. The formation segment is the final part of the procedure and consists of two pauses and a transition during which the aircraft maintains formation with the site aircraft.

Flight Mode

Parameter Description
Flight Mode

Select the type of motion that the aircraft is engaged in at the reference state from the drop-down menu. The options are:

  • Forward Flight - Climb
  • Forward Flight - Cruise
  • Forward Flight - Descend
  • Hover
  • Landing
  • Takeoff

The flight mode governs aerodynamics and propulsion calculations during the procedure and the attitude of the aircraft during transitions.

Start Formation/Recover Time

The time at which the formation begins. The Minimum Time and Maximum Time fields display the minimum and maximum times in the scenario at which formation between the site aircraft and the aircraft might be possible. You can manually enter a value in the Start Time field or click Find First Valid Start Time to have Aviator calculate the earliest valid formation time and populate the field with that value; specify search criteria in the window that opens. For more information on the options available for time instances and start times, see Time Options.

A first valid time cannot be found if another procedure in the mission has a fixed time and there is no delay between that procedure and this one. Select the Consider previous procedure(s) for Minimum Time check box to modify the calculated minimum time according to the procedures that this aircraft has performed in the mission so far.

Formation Point

The position - relative to the site aircraft- that the aircraft will be locked onto while in formation; click to open the Select Position Point window to choose a different reference point. The aircraft will hold formation at this point without condition. Select the Interpolate Point Pos / Vel check box to allow Aviator to use interpolation to determine the formation point's speed and position; this option should speed up the processing time required to calculate the procedure. Click Reset to reset the point definition to the default.

While In Formation

Parameter Description
Altitude Offset

The altitude distance between the aircraft and the formation point during either the First or Second Pause.

In most cases, the following aircraft will fly at this offset during the first pause of the formation; the only exception is when the formation is the first procedure in the mission, in which case the following aircraft will fly at this offset during the second pause.
Fuel Flow Source

The fuel flow of the aircraft while in formation; select from the following options:

  • Takeoff Perf Model - uses the Takeoff performance model's setting.
  • Cruise Perf Model - uses the Cruise performance model's setting.
  • Landing Perf Model - uses the Landing performance model's setting.
  • VTOL Perf Model - uses the VTOL performance model's setting.
  • Aero/Propulsion - uses the fuel flow calculated by the aerodynamics and propulsion strategies defined in the active acceleration performance model; if the acceleration performance model is not set to calculate fuel flow, then fuel flow will not be calculated for this performance model, either.
  • Override - manually specify the fuel flow in the Override Fuel Flow field.
Consider Acceleration for Fuel Flow Select this check box to modify the calculated fuel flow rate according to the acceleration of the aircraft during the procedure.

In Formation Times

Parameter Description
First Pause If the procedure is the first of the mission, the First Pause defines the amount of time that the aircraft will pause at a zero altitude offset; otherwise, it defines the amount of time that the aircraft will pause at the Altitude Offset.
Transition Time If the procedure is the first of the mission, the Transition Time defines the amount of time that the aircraft will spend transitioning to the Altitude Offset; otherwise, it defines the amount of time that the aircraft will spend transitioning from the Altitude Offset to a zero altitude offset.
Second Pause If the procedure is the first of the mission, the Second Pause defines the amount of time that the aircraft will pause at the Altitude offset; otherwise it defines the amount of time that the aircraft will pause at a zero altitude offset.
Display Step Time The time interval at which ephemeris is generated for display purposes.

Enroute Options

Enroute Options define the turning performance characteristics of the aircraft during enroute segments of the procedure.

Table - Enroute Options ParametersClosed

Option Description
Use Max Speed When Computing Turn Radii Select this check box to force the aircraft to maintain its cruise speed when turning, even if doing so will result in the aircraft making a turn large enough that it takes longer to complete than it would complete a slower, smaller turn.
Turn Factor The Turn Factor is the maximum amount - expressed as a multiplier - that the turn radius will be increased to minimize the bank angle required to complete the turn. The factor is applied only to turns that are performed enroute to the procedure's first control point. The full circles that correspond (or are tangent) to the start/stop turns at the extended radius may not intersect if the factor is set high enough. This parameter is a limit and may not actually be achieved due to the requirement to generate an appropriate turn sequence. You can adjust the slider or enter the value manually in the box, with the minimum value being 1 and the maximum value being 10.

Vertical Plane Options

Vertical Plane Options define the flight path angle of the aircraft.

Table - Vertical Plane Options Closed

Option Description
Flight Path Angle The flight path angle that the aircraft will have when it arrives at the beginning of the First Pause.
Radius Factor The Radius Factor is the maximum amount - expressed as a multiplier - that the radius of a vertical curve will be increased to minimize the flight path angle required to complete it. The full circles that correspond (or are tangent) to the start/stop curves at the extended radius may not intersect if the Radius Factor is set high enough. This parameter is a limit and may not actually be achieved due to the requirement to generate an appropriate curve sequence. You can adjust the slider or enter the value manually in the box, with the minimum value being 1 and the maximum value being 10.

Delay Options

Table - Delay OptionsClosed

Option Description
Include Delay - enables Auto Duration Select this check box to insert a delay at the beginning of the procedure, which will allow Aviator to adjust the timing of the procedure to increase the likelihood of achieving the formation. Select the turn direction of the delay in the Delay Turn Dir field; if the mode is set to Auto, Aviator will determine the turn direction.

Delay Cruise Airspeed

Delay Cruise Airspeed parameters define the airspeed performance characteristics of the aircraft during the delay segment of the procedure.

Table - Delay Cruise Airspeed ParametersClosed

Parameter Description
Delay Cruise Airspeed

Select the method for determining the airspeed while delaying from the following options:

  • Minimum Airspeed - constant airspeed at the minimum cruising airspeed for the aircraft.
  • Max Endurance Airspeed - variable airspeed that maximizes the length of time that the aircraft can remain in flight.
  • Max Range Airspeed - variable airspeed that maximizes the distance that the aircraft can fly.
  • Max Performance Airspeed – a custom performance airspeed and fuel flow that you can use to model specific flight conditions.
  • Maximum Airspeed - constant airspeed at the maximum cruising airspeed for the aircraft.
  • Other Airspeed - constant, manually defined airspeed.

With the exception of Other Airspeed, the actual airspeed will be defined by the currently selected cruise performance model, or possibly by the currently selected climb or descent performance model if the aircraft is climbing or descending.
Airspeed Displays the airspeed while delaying. If the airspeed type is Other Airspeed, enter the desired airspeed value; otherwise, the calculated value will be displayed and cannot be edited. Select a reference from the drop-down menu - true airspeed (TAS True Airspeed: the speed that the aircraft is moving relative to the airmass that it is flying in.), calibrated airspeed (CAS Calibrated Airspeed: the speed reported by the airspeed indicator, corrected for position and instrument error.), equivalent airspeed (EAS Equivalent Airspeed: the airspeed at sea level (International Standard Atmosphere) at which the dynamic pressure is equal to the dynamic pressure at the aircraft's current true airspeed and altitude.), or Mach The ratio of the aircraft's speed and the speed of sound at the aircraft's altitude, with local atmospheric conditions. number.