Static Port

A Static Port is an opening that measures ambient static air pressure. It is usually placed on a flat area of the fuselage, away from airflow disturbances — it feels only the atmospheric pressure, not the ram pressure of the oncoming air.

The static port and the pitot tube together form the "pitot-static system" — icing or blockage of this system has been a factor in several aviation accidents, which is why modern airliners treat its redundancy and anti-icing design so seriously.

The Static Port (ccpe:static_port) is an attachable pressure-sensor block. When installed on a physics body (Sable sub-level), CC:Tweaked computers on that body can read the pressure and altitude at the static port's own position via ccpe.sensor_system.

Reading reference point

ccpe.sensor_system reads at the static port's own position (not the physics body origin):

• Each static port: project its plot position to world → altitude (world Y) and pressure (Sable DimensionPhysicsData, same formula as simulated:altitude_sensor; sea level = 1.0) at that point.
• A body can have multiple static ports, each with its own independent readings.

Lua API

A computer on the same physics body (including constraint chains) uses require("ccpe.sensor_system"):

Method	Returns	Description
isOnBody()	boolean	Whether the computer is on a physics body
getBodyId()	string / nil	UUID of the containing physics body
getSensors()	table	Snapshot of all sensors (same tick): {type, pos={x,y,z}, pos_rel={x,y,z}, altitude, pressure}; pos is relative to the physics body origin, pos_rel is relative to the current computer (recommended for telling ports apart)
getAltitude()	number / nil	Altitude (world Y) of the most recently placed static port
getPressure()	number / nil	Pressure of the most recently placed static port (atmosphere fraction, sea level = 1.0)
getAverageAltitude()	number / nil	Simple average altitude over all static ports
getAveragePressure()	number / nil	Simple average pressure over all static ports
getWeightedAltitude()	number / nil	Distance-weighted average altitude (weight = 1/distance from the body origin, IDW)
getWeightedPressure()	number / nil	Distance-weighted average pressure (weight = 1/distance from the body origin, IDW)

• With no static port on the body, getAltitude()/getPressure() return nil and getSensors() returns an empty array; the average / weighted-average methods also return nil.
• Readings refresh once per tick (at most 1 tick stale); Lua reads perform zero main-thread scheduling, so high-frequency calls are effectively free.
• Weighted-average edge cases: a port exactly at the body origin (distance ≈ 0) has infinite weight, so its reading is returned directly; with a single port, the average / weighted average equal that port's reading.

local ss = require("ccpe.sensor_system")

print("onBody:", ss.isOnBody())
print("bodyId:", ss.getBodyId())

local sensors = ss.getSensors()
for i, s in ipairs(sensors) do
    print(i, s.type,
          "pos:", s.pos.x, s.pos.y, s.pos.z,
          "pos_rel:", s.pos_rel.x, s.pos_rel.y, s.pos_rel.z,
          s.altitude, s.pressure)
end

-- Convenience: most recently placed static port
print("alt:", ss.getAltitude(), "press:", ss.getPressure())

-- Averages / distance-weighted averages (weight = 1/distance from body origin)
print("avg alt:", ss.getAverageAltitude(), "avg press:", ss.getAveragePressure())
print("wavg alt:", ss.getWeightedAltitude(), "wavg press:", ss.getWeightedPressure())

Multiple static ports

A body can carry several static ports, each with independent altitude/pressure readings (same-tick snapshot, e.g. for differential-pressure math):

local sensors = ss.getSensors()
if #sensors >= 2 then
    print("pressure difference:", sensors[1].pressure - sensors[2].pressure)
end

After a server restart, getAltitude()/getPressure() may point at a different static port

If the body has only one static port, this warning does not apply.

getAltitude()/getPressure() return data from the most recently placed static port, determined by registration order (= placement order), which is only valid within the current session. After a server restart, static ports re-register in chunk-load order, so these two methods may point at a different static port, and the target may differ between restarts.

If your script must reliably read a specific port, use getSensors() and identify it by pos_rel (position relative to the current computer) — pos (relative to the body origin) drifts when blocks are added to or removed from the body, since the origin (center of mass) moves:

local sensors = ss.getSensors()
for _, s in ipairs(sensors) do
    if math.abs(s.pos_rel.y - 2) < 0.5 then  -- e.g. the port 2 blocks above the computer
        print("that port's pressure:", s.pressure)
    end
end