Flight Inspection

Flight Inspection

In the field of flight inspection FCS inspects the following systems: ILS CAT I to III, MLS, PAR, (D)VOR, DME, TACAN, NDB, GBAS, VHF and UHF radio direction finders and COM systems, PAPI and visual aids/air field lighting, as well as special flight inspections of disturbed NAV systems or GPS interferences.

In the field of flight validation, FCS validates RNP (GPS RNAV and conventional) procedures), P-RNAV (DME-DME), LPV / APV SBAS precision approaches. Supplanting GPS based procedure validation, FCS performs ARINC 424 and FMS database validation services.

The third main segment of FCS flying activities is flight testing of surveillance systems, i.e. primary radar, secondary radar (SSR/ MSSR) and multilateration (MLAT/WAM) systems, as well as PAR. In the surveillance domain, FCS also performs 1030/1090 MHz special measurements.

En-route Navaids

„Classical“ En-route Navaids flight checked by FCS comprise (D)VOR systems, DMEs and NDB system. While some of these legacy navigational aids are being decommissioned, the remainder is currently being replaced by a new system generation in many countries. This is to provide a fallback infrastructure for GNSS, and as many older transport aircraft still require these conventional navaids for navigation purposes. The flight inspection interval usually is one year.

» Flight Validation P-RNAV


FCS carries out commissioning, routine and special flight inspections of ILS Localizer, Glide Path, Markers, and approach DME subsystems, applying latest flight inspection technology and precise flight inspection procedures.

FCS D-CFMD and D-CFME flight inspection aircraft employ the highly precise phase continuity DGPS position system, which, combined with further aircraft sensors achieve an absolute position accuracy of 10 cm, allowing flight inspection even in adverse weather conditions. A laser tracker is employed by FCS as an additional sensor for commissioning flight inspections or when GPS DOP conditions are poor.

Once yearly, runway visual approach aids are also checked and assessed simultaneously with ILS inspections.

In order to minimize the disturbance of regular air traffic, FCS carries out ILS flight inspections (required twice yearly) at major hub airports at night.

For the inspection of the ILS, flights must deviate both laterally and horizontally from the published approaches; each runway must be approached a number of times for a calibration. In the process, ILS signals are recorded and evaluated for consistency with the tolerances specified by the ICAO.


FCS D-CFME is the sole aircraft approved for flight inspection in Europe, equipped with a GBAS receiver integrated into the flight inspection system. The focus of GBAS flight inspection is the coverage of the VDB correction signal, complementing extensive measurements on the ground. Thanks to the FCS capability of field strength measurement traced to SI norms, VDB coverage assessment is performed within the measurement uncertainty stipulated by ICAO as a unique service feature of FCS.

Radar Flight Testing

Surveillance systems (radar, MLAT/ WAM, ADS-B) are safety-critical and expensive infrastructure investments forming the backbone of ATM with a life span often exceeding 20 years. Therefore, the commissioning flight check is one of the most important milestones in the system life cycle to confirm that the system is within the required specifications and fit for its operational use, as governed by ICAO or EUROCONTROL documents for radar. Flight testing of a surveillance system by FCS typically comprises:

  • supply of critical quality figures such as probability of detection (PD) and resolution
  • coverage evaluation on test radial and arrival and departure routes
  • system optimization, e.g. tilt in the case of radar
  • general certification of system performance.

For radar flight testing, FCS usually employs a specially equipped Learjet 35 aircraft, as described under resources

SASS-C Recording

FCS performs the essential recording and radar data quality analysis work on the ground with the EUROCONTROL SASS-C toolset through special partnerships, thus ensuring complete and concise evaluation reports in accordance with the pertinent standards.

Special Flight Inspections

In case of detection of ground system deficiencies or other special occasions, FCS carries out special flight inspections using prop or jet aircraft. Optionally, FCS SISMOS technology is employed for extended analysis.

Using our new Carrier/Noise Monitor FCS is able to easily detect GPS interferences continuously during our routine flight inspection missions.

» IFIS Paper C/N Monitor