Monitoring for unstable approach of aircraft using specific energy

A method of identifying an unstable approach of an aircraft, performed using a flight management system (FMS) of the aircraft, the method comprising:

• determining a reference specific energy of the aircraft, wherein determining the reference specific energy of the aircraft comprises:
• determining a reference ground speed term comprising a reference speed according to a selected landing flap setting;
• and
• determining a reference height term based in part on data retrieved from a navigation database of the FMS;
• defining an energy range relative to the reference specific energy;
• determining, using an actual height and an actual ground speed of the aircraft, a specific energy of the aircraft during an approach phase of a flight;
• and
• generating a signal to cause an indicator of the specific energy of the aircraft, relative to the energy range, to be visually displayed using a flight instrument of the aircraft.

A system comprising:

• one or more computer processors;
• and
• a memory storing instructions that when executed by the one or more computer processors enable performance of an operation of identifying an unstable approach of an aircraft, the operation comprising:
• determining a reference specific energy of the aircraft, wherein determining the reference specific energy of the aircraft comprises:
• determining a reference ground speed term comprising a reference speed according to a selected landing flap setting;
• and
• determining a reference height term based in part on data retrieved from a navigation database;
• defining an energy range relative to the reference specific energy;
• determining, using an actual height and an actual ground speed of the aircraft, a specific energy of the aircraft during an approach phase;
• and
• generating a signal to cause an indicator of the specific energy of the aircraft, relative to the energy range, to be visually displayed using a flight instrument of the aircraft.