Final answer:
The question pertains to aviation, specifically the altitude at which a planned four-engine go-around should be initiated. The altitude varies based on various factors, but typically is no lower than 1000 feet AGL for IFR or 500 feet AGL for VFR, subject to specific airline procedures or approach protocol.
Step-by-step explanation:
The question you've asked relates to a procedure in aviation known as a planned four-engine go-around. Although the specific altitude at which a go-around should be initiated can vary based on the aircraft, the airline's procedures, and the situation, it is common for standard operating procedures to require that a go-around be initiated at a minimum altitude which ensures safety and allows for sufficient time for the maneuver to be completed successfully.
Regulations and standard operating procedures differ by country and airline, but a common practice is to plan a go-around no lower than 1000 feet above ground level during Instrument Flight Rules operations or 500 feet above ground level during Visual Flight Rules operations, unless a lower height is specified by the approach procedure or dictated by the pilot's judgment.
However, for the exact altitude, one would need to refer to the specific airline's operating manual or the aircraft's flight manual for go-around procedures.