APATC-1 vs PANS OPS vs MIPS safety altitude
Dear all,
Working in the Linconshire area, we've recently noted that various local terminal charts use differing MSAs, despite being based on the same mast. Cranwell and Coningsby use APATC-1 which has 2700'. Waddington and Barkston Heath use MIPS which has 2600'. Humberside uses PANS OPS(ICAO) which has 2700'.
The only information I've found in the books is that PANS OPS will calculate safety altitude using metres then convert to feet, which may give slight discrepancies when rounded up (Military Manual of Air Traffic Management- page 36).
Is anyone aware of anything else that might be causing the differing values?
Thanks for you help