The assessment of the vertical position of the aircraft, in relation to the glide path angle (GPA) during theapproach is based on barometric data.

The calculated true air speed (TAS) is based on the standard atmosphere and any significant differences willlead to an approach sneed which could be too slow or too fast.

The difference between true height and published decision height has to be limited to a maximum value.

Static vents can be blocked due to icing when approaching in IMC, hence leading to a loss of verticalquidance.

218

A 238

B 038

058

can both be used, but because their information is NOT compatible an aircraft CANNOT use

both systems 

are two separate systems and only GPS is covered by EU regulations so only that service

can be used by European Operators.

can both be used in a suitably equipped aircraft as the systems are compatible and their

functions are interoperable 

are two completely separate systems but only GPS is capable of providing approved

position data. 

A = refraction B = absorption C = reflection 

Turbulence in cloud that has precipitation

clear air turbulence

Precipitation

Wet snow and turbulence in cloud that has precipitation

one LRNS using input from VOR/DME or DME/DME RNAV equipment.

one LRNS comprising an INS, an IRS FMS or a GNSS.

two LRNSs comprising an INS, an IRS FMS or a GNSS.

two LRNSs using input from VOR/DME or DME/DME RNAV equipment.

1300 Hz.

3000 Hz.

400 Hz.

1500 Hz.

Fly towards the area where the contours are the steepest and avoid any areas that are yellow.

Aim to avoid the thunderstorm by at least SNM so as to avoid any turbulence.

The areas that have the worst precipitation are coloured yellow and they should be avoided at all times.

Fly on the upwind side of the thunderstorm and avoid red or magenta coloured areas.

INS and clock 

Barometric altimeter and clock only.

On-board clock to aid time reference and SBAS

AAIM with Baro. 

GBAS uses the exact same satellites as the receiver in the aircraft. 

GBAS uses the signals from at least 3 geostationary satellites.

4 satellites are required for GBAS operations. 

GBAS requires at least 5 satellites to detect and exclude the possible faulty satellite.