Name	Data Type	Definition
designator	TextDesignatorType	The designator of the touch down and lift-off area.
length	ValDistanceType	The value of the physical length of the touchdown and lift-off area.
width	ValDistanceType	The value of the physical width of the touchdown and lift-off area.
slope	ValSlopeType	The slope (rate of upward inclination of the surface from the horizontal) of the surface of a touch down and lift-off area.
helicopterClass	CodeHelicopterPerformanceType	The class of a helicopter (based on its performance during a critical power unit failure after take-off) associated with a touch down and lift-off area.
abandoned	CodeYesNoType	An indicator that the touch down and lift-off area is no longer in operational use, but it is still physically present and visible, although usually in a degraded state.

Association	Multiplicity	Role	To	Role description
isSituatedAt	0..1	associatedAirportHeliport	AirportHeliport	The airport the TouchDownLiftOff zone is associated with.
hasSurfaceDescribedBy	0..1	surfaceProperties	SurfaceCharacteristics	Surface characteristics of the touch down lift off zone.
hasAimingPoint	0..1	aimingPoint	ElevatedPoint	Aiming point for the TouchDownLiftOff zone.
isContaminated	0..*	contaminant	TouchDownLiftOffContamination
hasAnnotations	0..*	annotation	Note
hasExtent	0..1	extent	ElevatedSurface	Extent of the TouchDownLiftOff zone.
isSituatedOn	0..1	approachTakeOffArea	Runway	The approach and take off runway area containing the touchdown lift off zone.
isOperationalBy	0..*	availability	ManoeuvringAreaAvailability	The operational status of the TouchDownLiftOff area.

From	Association	Multiplicity	Role	To	Role description
TouchDownLiftOffLightSystem	isProvidedFor	0..1	lightedTouchDownLiftOff	The touch down lift off zone lit by the TouchDownLiftOffLightSystem.
DesignatedPoint	isAtCentreOf	0..1	aimingPoint	The aiming point on the Touch Down Lift Off area.
LandingTakeoffAreaCollection	isLocatedAt	0..*	TLOF	A load bearing area on which a helicopter may touch down or lift-off referenced by the procedure.
TouchDownLiftOffMarking	isMarkedOn	0..1	markedTouchDownLiftOff	The TouchDownLiftOff marked.
Navaid	isInstalledAt	0..*	touchDownLiftOff
SignificantPoint		0..1	aimingPoint	The point at the centre of the TLOF.
GuidanceLine	connects	0..*	connectedTouchDownLiftOff	The TouchDownLiftOff zone connected by the Guidance line.
TouchDownLiftOffSafeArea	protects	0..1	protectedTouchDownLiftOff	The protected TouchDownLiftOff.

1 - Navaids , 1 - Runway , 1 - Significant Points , 1 - Surface Contamination , 1 - Surface Marking , 1 - TLOF , 2 - AirportHeliport Association , 2 - Designated Point , 2 - Guidance Line , 2 - Surface Lighting Elements , 2 - TLOF Protection Area , 4 - Manoeuvering Area Availability , 5 - LandingTakeOffArea