The approach surface tested today, the rest in development

Frequently Asked Questions

Which surfaces does TarmacView test today?

The approach surface only. Flight planning tests obstacles against the Annex 14 approach surface and shows a warning when one penetrates. Annex 14 defines more for a runway's code and approach classification: the inner approach where applicable, the take-off climb surface, the transitional and inner transitional surfaces, the inner horizontal surface, the conical surface and, for precision approach runways, the balked landing surface. Testing against those is part of the full evaluation, which is in development. Which of them exist for an aerodrome, and how far out each reaches, follows from the runway code number and whether the approach is non-instrument, non-precision or precision.

Does anyone fly the whole conical surface?

No, and nobody should. The outer surfaces reach kilometres from the runway, and flying every square metre of them would be a very long way of finding out what the obstacle register already says. The sensible method tests every registered obstacle against the constructed surfaces first, which is a computation, and goes to look only at the objects that penetrate or come within a margin and at the areas where the register is old enough that vegetation or new construction cannot be ruled out. Today that computation exists for the approach surface and appears as a warning in flight planning. The other surfaces are part of the evaluation in development.

Where do the obstacle heights come from?

From the register, not from imagery. Each obstacle carries a height above ground and its MSL and ellipsoid (HAE) heights, entered by hand, imported from OpenAIP or seeded from the Slovak eAIP, so a height is only as good as its source. TarmacView does not measure obstacle heights from drone imagery today. A hard-edged object such as a mast has a single top, while the crown of a tree has none and grows between entries. Where a decision depends on centimetres, a ground survey of that one object is the right next step.

Is this a substitute for the certified obstacle survey?

No. Obstacle data that goes into the AIP or into an electronic terrain and obstacle data set has to meet the accuracy, integrity and traceability requirements of Annex 15, and that is the work of a licensed surveyor operating a formal data chain. The register answers a different question: what the aerodrome has on record, and whether the recorded obstacles penetrate the approach surface. It can show a surveyor what is already known, and it gives the operator an exportable picture between certified surveys.

What does the aerodrome have to provide?

The runway threshold positions, the runway code, the approach classification and whatever obstacle data already exists. The register can be started from OpenAIP or, for Slovak aerodromes, from the eAIP, and obstacles can be added by hand. A register can only warn about obstacles that are in it, so its completeness is the operator's responsibility. Heights entered with a stated source are easier to defend later than heights with none.

What do we get when something penetrates?

A warning in flight planning that the obstacle penetrates the Annex 14 approach surface. It is a planning warning, not a report. The obstacle register can be exported on the airport data sheet as JSON, CSV or PDF, and flight-plan KML can include obstacles as no-fly polygons. What you do not get is a decision about whether the penetration is acceptable. That is an aeronautical study, and it belongs to the operator and the authority.

What about the new obstacle free and obstacle evaluation surfaces?

ICAO has adopted a revised obstacle surface framework for Annex 14 that replaces the limitation surface set with obstacle free surfaces and obstacle evaluation surfaces, with a transition period during which states move across. Until your authority adopts the new framework, your certification is against the surfaces this page describes, and the approach surface test uses those.