Warning Helicopters Flying Permanent UK Road Sign
- Post Mountable with 2 fixing rails
- Class 2 R2/RA2 Reflective
- Available in 450mm, 600mm, 750mm, 900mm Tri
Diagram 558.1 is situated on roads adjacent to airfields, the is used to prepare road users from sudden appearances of helicopters or loud aircraft noises.

Material: R2/RA2 reflective overlay on aluminium composite backing
Fixing Method: 2 fixing rails for post mounting
Reflectivity: Class 2 R2/RA2
As per the UK Highways Traffic Sign Manual Chapter 4 - Warning Signs page: 66 The following advice is given:
13.1.3. Where helicopters are likely to be encountered, the sign to diagram 558.1 (S2‑2‑47, see Figure 13-3) may be used.