Level acceleration
A litttle history - the level accelerations segment was added to the PANS-OPS missed approach and departure criteria as a result of input from the Airworthines Committee back in the mid 70s. However, it quickly became apparent that it was unrealistic from an operational perspective. It resulted in the departure from Frankfurt being limited by the Alps and the inability to operate at all out of Aukland. It took four years and support from Mike Cowley (Performance Manager from NZ) to get the criteria removed from PANS-OPS. It was then that the statements were added that PANS-OPS covered normal operations, and that contingency procedures were the responsibility of the operator.
The requirement for the Type C chart was also added to Annex 4. Unfortunately no State produced that chart, leaving the operator on his own and without obstacle data from the State. Despite pressure at various ICAO meetings, nothing has changed - perhaps the combination of legal liability and cost is the reason.
There are also other anomalies - for departures, one group of States require assessment of an engine failure at any point after V1, another only at V1.
Also, there is no ICAO guidance on how to take benefit from the lower OCA/H promulgated by Some States for aircraft capable of missed approach gradients above 2.5%. This is left to States and operators to negotiate between themselves. A proposal was made at OCP/13 for an appropriate body to provide guidelines on the treatment of the missed approach critera. Unfortunately it seems to have got lost in the works - perhaps because it is so aircraft type specific.
If that is not enough, there is the long standing difference in missed approach between the FAA 3.3% expanding margin and the PANS-OPS 30m/50m stepped margin. Likewise the FAA Airmans Handbook requires the whole missed approach track to be followed, whereas PANS-OPS caters for protection of an early turn in the missed approach.
The final word? Be happy if you have a good performance engineer behind you.