Synthetic Vision System (SVS)
A 3D terrain picture on the PFD — what it's built from, when it turns itself off, and the one rule about attitude.
Source: AW169 / AW169 EP RFM Supplement 18 (Synthetic Vision System). Same avionics suite (Collins MFD-2810) on both configurations.
What it is
SVS, embedded in the Collins MFD-2810, builds a three-dimensional synthetic view of the terrain around the aircraft from precise navigation sensor inputs plus a high-resolution terrain, obstacle and runway/heliport database. It displays airport runways and helipads, obstacles higher than 50 ft, and a Flight Path Vector (FPV) showing the aircraft's actual trajectory. Selected on the PFD's attitude/navigation area via the PFD menu or the on-side DCP; the FPV and obstacle layers can be switched off independently.
The one rule that matters most
Pitch and roll attitude are read from the basic PFD symbology, never from the SVS picture itself. The SVS terrain image is a situational-awareness layer drawn on top of the real attitude display, not a replacement for it.
When it turns off on its own
SVS must not be used for navigation, and must not be selected ON during approach and landing. It won't display at all with the central MFD powered off or reverted to PFD format. It is automatically inhibited whenever aircraft attitude exceeds 30° nose up/down or 50° bank left/right, and re-selects itself automatically once attitude comes back within ±10° pitch and ±5° roll.
Failures
SVS FAIL: total loss of the function. SVS DEGR: partial loss — obstacles, FPV, or runway/airport/helipad data missing, rather than everything. SVS is not available at all if the PFD itself has failed. GPS POS and GPS HT messages mean the SVS detected a mismatch between the two GPS receivers' position or height solutions — the response in both cases is the same: deactivate the SVS.