During a flight at FL 100 from Marseille (QNH 1012 hPa) to Palma de Mallorca (QNH 1015 hPa), an aircraft remains at a constant true altitude. The reason for this is that:

Question

Accepted Answer

The air at Marseille is warmer than that at Palma de Mallorca.

Answer

The air at Marseille is colder than that at Palma de Mallorca.

Answer

The altimeters are erroneous, and need to be tested.

Answer

One of the two QNH values may be incorrect.

During a flight at FL 100 from Marseille (QNH 1012 hPa) to Palma de Mallorca (QNH 1015 hPa), an aircraft remains at a constant true altitude. The reason for this is that:

Domanda 32, Meteorology - ATPL - Airline Transport Pilot license