Network Information

The X-Plane Connect network protocol is designed to extend the UDP data protocol provided by X-Plane. XPC's protocol is a strict superset of the X-Plane protocol.

Detailed information about the commands added by XPC are provided below.

The primary purpose of this page is to document the format of data as it travels over the network. For more information about the commands themselves, there is usually an obvious one-to-one mapping between these datagrams and commands described in the XPC Client Reference.

Format

The following section describes commands using the following format:

Each command is presented as a table with 3 rows. The first row shows the byte number of the packet. The second row indicates the type of the data field. Finally, the third row gives a descriptor of the field. Interesting descriptors are described in more detail below the table. The first 4 bytes of each command are always ASCII characters, and their descriptors are character literals.

Symbol	Data Type
x	Padding byte
C	ASCII Character
B	Byte
U16	Unsigned 16-bit integer
U32	Unsigned 32-bit integer
U64	Unsigned 64-bit integer
I16	Signed 16-bit integer
I32	Signed 32-bit integer
I64	Signed 64-bit integer
F	32-bit float
D	64-bit float
S	ASCII string

Strings

ASCII strings are always preceded by a single byte indicating their length. Strings are not null terminated.

Byte Order

All multi-byte fields are transmitted in little-endian byte order.

Commands

Quick Nav

BCOM | CONF | COMM | CONN | CTRL | DATA | DREF | ECOM | GETC | GETD | GETP | POSI | RESP | SIMU | TEXT | VIEW | WYPT

CONF

Summary: Sent in response to the CONN command on the new port.

Format:

0	1	2	3	4	5
C	C	C	C	x	B
C	O	N	F	-	id

id: The internal id of the client. Because this value is not exposed to the client anywhere else, it is not actually useful. It is kept for legacy compatibility.

COMM

Summary: Executes a momentary X-Plane command.

Format:

0	1	2	3	4	5	6
C	C	C	C	x	B	S
C	O	M	M	-	n	cmd

n: The length of cmd.

cmd: The name of the command to execute.

BCOM

Summary: Begins an X-Plane command. Format:

0	1	2	3	4	5	6
C	C	C	C	x	B	S
B	C	O	M	-	n	cmd

n: The length of cmd.

cmd: The name of the command to begin executing.

ECOM

Summary: Ends an X-Plane command.

Format:

0	1	2	3	4	5	6
C	C	C	C	x	B	S
E	C	O	M	-	n	cmd

n: The length of cmd.

cmd: The name of the command to stop executing.

CONN

Summary: Sets the port used to send data back to the sending client.

Format:

0	1	2	3	4	5
C	C	C	C	x	U16
C	O	N	N	-	port

port: The port on which future data will be sent.

CTRL

Summary: Sets the control surfaces of the specified aircraft.

Format:

0	1	2	3	4	5	9	13	17	21	22	26	27
C	C	C	C	x	F	F	F	F	B	F	B	F
C	T	R	L	-	e	a	r	t	g	f	ac	sb

e: Elevator. Value should be in the range [-1, 1].

a: Aileron. Value should be in the range [-1, 1].

r: Rudder. Value should be in the range [-1, 1].

t: Throttle. Value should be in the range [0, 1].

g: Gear. Value should be 0, 1, or -1 (-1 toggles).

f: Flaps. Value should be in the range [0, 1].

ac: Aircraft number.

sb: Speed brakes. Value should be in the range [-0.5, 1.5].

DATA

Summary: Sets data rows.

Format:

0	1	2	3	4	5	9	...	37	...
C	C	C	C	x	U32	F	F	F	-
D	A	T	A	-	r1	v1^1	...	v1^8	...

The DATA command consists of any number of rows. No length byte is used; the length is determined by dividing the packet length by 36 instead.

DREF

Summary: Sets the value of an X-Plane dataref.

Format:

0	1	2	3	4	5	6	6+n	7+n	...	7+n+4(m-1)
C	C	C	C	x	B	S	B	F	F	F
D	R	E	F	-	n	dref	m	v^1	...	v^m

n: The length of dref.

dref: The name of the dataref being set.

m: The number of values in the dataref.

v^1 to v^m: The values of the dataref.

GETC

Summary: Sends a request to the plugin to get the control surface information for a specific plane. The plugin will respond with a CTRL packet.

Format:

0	1	2	3	4	5
C	C	C	C	x	B
G	E	T	C	-	n

n: The aircraft number to get information for.

GETD

Summary: Gets the value of one or more datarefs. This command's structure is difficult to represent in tabular form, but is fairly straightforward in practice. In short, the command has the standard header, followed by the number of datarefs being requested, followed by the dataref names.

Format:

0	1	2	3	4	5	6	7	7+n^1+1	...		Complicated
C	C	C	C	x	B	B	S	B	S	B	S
G	E	T	D	-	c	n^1	dref^1	...	...	n^c	dref^c

c: The number of datarefs.

n^1 to n^c: The length of each dref.

dref^1 to dref^c: The name of each dataref.

GETP

Summary: Sends a request to the plugin to get the position of a specific plane. The plugin will respond with a POSI packet.

Format:

0	1	2	3	4	5
C	C	C	C	x	B
G	E	T	P	-	n

n: The aircraft number to get information for.

POSI

Summary: Sets the position and orientation of an aircraft

Format:

0	1	2	3	4	5	6	10	14	18	22	26	30
C	C	C	C	x	B	D	D	D	F	F	F	F
P	O	S	I	-	ac	lat	lon	asl	r	p	h	g

ac: Aircraft number. lat: Latitude lon: Longitude asl: Altitude (meters above sea level) r: Roll (degrees) p: Pitch (degrees) r: Roll (degrees) h: Heading (degrees) g: Gear (0 to retract, 1 to extend)

RESP

Summary: Returns value of one or more datarefs in response to the GETD command. This command's structure is difficult to represent in tabular form, but is fairly straightforward in practice. In short, the command has the standard header, followed by the number of datarefs that were requested requested, followed by the data itself

Format:

0	1	2	3	4	5	6	7	Complicated
C	C	C	C	x	B	B	F[]	...
G	E	T	D	-	c	n^1	data^1	...

c: The number of datarefs.

n^1 to n^c: The number of values in the result.

data^1 to data^c: The result for each data ref. Values are always float, even if the actual type of the dataref is int or double.

SIMU

Summary: Enables or disables the physics simulation in X-Plane.

Format:

0	1	2	3	4	5
C	C	C	C	x	B
S	I	M	U	-	op

op: The operation to perform. 0 disables physics, 1 enables, and 2 toggles.

TEXT

Summary: Sends a string to be drawn on the screen.

Format:

0	1	2	3	4	5	9	13	14
C	C	C	C	x	I32	I32	B	S
T	E	X	T	-	x	y	n	str

x: The x coordinate where the string will be drawn.

y: The y coordinate where the string will be drawn.

n: The length of the string. Setting this to 0 will clear the current string and disable drawing.

str: The string itself.

VIEW

Summary: Changes the camera mode in X-Plane

Format:

0	1	2	3	4	5
C	C	C	C	x	I32
V	I	E	W	-	type

type: The command key associated with the desired view.

WYPT

Summary: Manipulates a sequence of waypoints drawn in the world.

NOTE: This command relies on OpenGL. It will not work if using Vulkan.

Format:

0	1	2	3	4	5	6	7	...	6+4(3n-1)
C	C	C	C	x	B	B	F	F	F
W	Y	P	T	-	op	n	v^1	...	v^3n

op: The operation to perform. 1 to add, 2 to remove, 3 to clear.

n: The number of points.

v^1 to v^3n: Values representing each point. Each triplet in this sequence is treated as a (lat, lon, alt) point.

##GETT Summary: Request terrain information at AC location or specified coordinates

Format:

0	1	2	3	4	5	6	14	22
C	C	C	C	x	B	D	D	D
G	E	T	T	-	ac	lat	lng	alt

ac: Aircraft number

lat: The latitude of the point to probe, or -998 to probe the aircraft's current location.

lng: The longitude of the point to probe, or -998 to probe the aircraft's current location.

alt: The altitude of the point to probe. Note that the altitude must be below the terrain height.

##TERR Summary: Response to a GETT query

Format:

0	1	2	3	4	5	6	14	22	30	34	38	42	46
C	C	C	C	x	B	D	D	D	F	F	F	F	F
T	E	R	R	-	ac	lat	lng	alt	nx	ny	nz	wet	status

ac: Aircraft number

lat: Probe latitude. Either the value given to GETT or the current aircraft latitude.

lng: Probe longitude. Either the value given to GETT or the current aircraft latitude.

alt: Terrain height above msl at the coordinates specified by (lat, lng).

nx: Terrain normal X.

ny: Terrain normal Y.

nz: Terrain normal Z.

wet: 0.0 if the terrain above the point is dry land.

status: Terrain probe status.