Pans-Ops and Terps

27.06.2008

Submission:

In the UK military procedures are designed to the NATO TERPS system which is basically an American system. The visibility minima are generated by the necessity to avoid obstacles in the visual segment visually. These obstacles are those which penetrate the 1:34 and 1:20 obstacle clearance surfaces (I believe - correct me if I am wrong). Civil aircraft, however, are allowed to ignore these obstacles and use the normal runway lighting and DH criteria to derive their minima. Question: does PANS OPS measure these surfaces and do they affect the OCL/DH

I am no expert in these things but I think I know a couple: 1. The circling domains are much smaller in TERPS (impossibly so, some would say). 2. TERPS generates its own minimum visibility criteria (unlike PANS OPS which generates only a DH) thus many military approaches have a min RVR of 1400m whereas a civil aircraft would typically have a min RVR of about 600m under JAR at the same airfield (see UK IAIP). The military do not really know whether they are bound by these figures or whether they may fly to JAR minima. TERPS seems to have a concept of 'obstacles that have to be avoided visually after DH' if they penetrate certain surfaces (at Kinloss the windsock is one of these; arguably it should be lit at night (it isn't)). NB.NATO procedures in Europe are often TERPS procedures.


George Morris - Military Flight Simulator Instructor, Thales, United Kingdom