One of important specialized services in Polish Air Navigation Services Agency (PANSA), monitoring the safety of traffic in Poland's airspace is the Flight Inspection.
The Flight Inspection is charged with monitoring the accuracy of ground-based navigation aids, in accordance with recommendations and regulations of the ICAO and Polish Civil Aviation Office. There are close to 100 such devices located at airports and under the corridors of Poland's airways. Highly specialized inspectors periodically check the proper operation of navigation and landing aids: VHF Omni-directional Range (VOR and DVOR), Distance Measuring Equipment (DME), Non-directional Beacon (NDB) and Instrument Landing System (ILS). Flight Inspection also inspects runway, approach lighting and Precision Approach Path Indicators (PAPI).
In order to fulfill its mission, Polish Flight Inspection utilizes two L-410 UVP-E 15 Turbolet aircrafts (SP-TPA and SP-TPB) equipped with sophisticated measuring devices, in conjunction with GPS and ground-based optical surveying instruments. These aircrafts are known in Polish aviation circles as "Papuga" - "The Parrot". This nickname dates from tail painted in characteristic color strips.
Inspectors use the Parrot to verify the accuracy of navigational readings. If any minor deviations from specified tolerances are found, appropriate instructions are issued to ground-based staff and the equipment is checked again. If more significant problems are detected, the navigation aid is removed from service and rechecked after required repairs have been completed.
All types of lighting aids, both steady and flashing, are subject to monitoring - threshold, end, edge and touchdown zone lights. Every irregularity such as improper angular adjustment in horizontal and vertical planes, lack of a color filter, damaged housing or an inoperative light source, is observed by the onboard inspector and recorded photographically as a supplement to the written findings. It is also necessary to monitor and adjust lighting intensity to avoid "blinding" aircraft crews.