Weather Radar RTA-4112
Modes, ranges, controls, and the one hard limitation on what this radar is allowed to be used for.
Source: AW169 / AW169 EP RFM Supplement 12 (Weather Radar RTA-4112 — General Information, Limitations, Normal Procedures, Malfunction Procedures) and Section 7 (System Description, OES — Weather Radar RTA-4112). Verified identical between AW169 and AW169 EP.
What it is
A fully automatic radar that displays significant weather data at all available ranges and altitudes, at all times, with a clutter-free display. It also does beacon detection and terrain mapping. Hardware: a 12 in flat-plate antenna in the nose radome, an antenna drive unit (moves the antenna up to 120° in azimuth, 32° in elevation), and a transceiver with separate receivers for weather and beacon signals, feeding the PFDs and MFD.
Two independent configurations exist side by side: L WXR (co-pilot's side) and R WXR (pilot's side). Controlled through the MFD drop-down menu (TILT and GAIN are also replicated on the MFD FPLN format bottom bezel).
Operating modes
| Mode | What it does | Range |
|---|---|---|
| Auto | Scans automatically, controls antenna tilt for optimal detection based on elevation/location, processes multiple scans to minimize ground clutter | 320 NM |
| Manual | Secondary mode / used after an automatic-mode failure — tilt and gain controlled manually | 320 NM |
| WX (Weather) | Weather returns for the selected tilt and gain | 320 NM |
| Turb (Turbulence) | Azimuth/range of hazardous turbulent areas | 40 NM |
| WX + T | Weather out to 320 NM combined with turbulence out to 40 NM — turbulent weather display takes priority over normal weather where they overlap | 320 / 40 NM |
| Map | Disables ground clutter suppression to show ground returns — coastlines, lakes, larger cities | 320 NM |
| Self-test | Checks display colors and system connections only | — |
| Standby | Antenna holds at bore-sight, transmitter off | — |
The one hard limitation
The radar must not be used for navigation or terrain avoidance. Everything else about the system — the automatic mode, the clutter suppression, the mapping mode — describes what it is good at showing, not a substitute for navigation or terrain awareness systems.
Ground transmission
The radar does not transmit while the helicopter is on the ground, unless the operator commands it to. Do not set it to transmit within 17 ft (5 m) of personnel or containers holding flammable or explosive material.
If the helicopter is on the ground with the radar set to anything other than Standby or Test, and the weight-on-wheels (WOW) microswitches fail, the radar will transmit unexpectedly — the caption WX TRANSMITTING displays. The response is simply to confirm the radar is set back to Standby.