Height Lock Transducer

Technical Information

Catalogue No: C0107
Category: Air Data
Object Type: Sensor/Transducer
Object Name: Height Lock Transducer
Part No: HL/10A/270/31
Serial No: 53174
Manufacturer: RW Munro
Division: Unknown
Year of Manufacture:
Width (mm):
Height (mm):
Depth (mm):
Weight (g):
Location: Archive Object Store

Height Lock
R.W.Munro Ltd London.


Marconi Collection Ref: 2023

This item is in a standard flight instrument case with a clear front which allows you to see the workings. The item has three small pipes on the back labelled ‘P’, ‘S’ and the third is blank. These inputs are from the Pitot tube and the Static Port and they drive an aneroid capsule. The difference between these two pressure inputs gives the dynamic pressure which is a measure of Indicated Airspeed (IAS). The capsule drives a mechanical system that moves a wiper along a wire wound resistor such that an electrical output is given via the three external tags marked ‘A’, ‘B’ and ‘C’. The electrical output may have been used to drive an Altimeter or Airspeed indicator but its title (Height Lock Transducer) would suggest that it was part of the Autopilot system that can be used to maintain a pre-set altitude.

The rear has the Inwards Goods number: "IG733479".

The internal mechanism is marked:
Inst. 53174"

Click to enlarge