The ‘drivers / reasons’ for this typically relate to the appropriate and applicable parts, sections, clauses etc. of any / all of the following (the list is not exhaustive):

• ICAO requirements (e.g. Safety Management System – SMS; Standards & Recommended Practices etc.)
• Statutory, Regulatory and similar requirements (National, Regional, Local etc.)
• IATA’s Airport Handling Manual (AHM), Ground Operations Manual (IOGM) and Standard Ground Handling Agreement (SGHA) requirements
• IATA’s ‘Safety Audit Programme for Ground Operations’ (ISAGO) requirements
• Involvement as part of parent airport’s AEP (Airport Emergency Plan) requirements 
  
• Client Aircraft Operators’ ERP (Emergency Response Plan) requirements (e.g. typically as stipulated as part of an associated IATA Standard Ground Handling Agreement – SGHA)
• GHA’s own requirements
• Best Practice
• Anything else required

In contrast to the catastrophic aircraft accident situation, aircraft related incidents (see definitions in sidebar) are relatively straightforward to deal with, typically requiring use of a GHA ‘Aircraft Incident Response Plan – IRP’ (typically around 5 to 10% the size & complexity of the corresponding GHA ‘Catastrophic Aircraft Accident Emergency Response Plan – ERP’)

Furthermore, aircraft related incidents are typically managed using ‘normal business’ type resources only (people, facilities, equipment etc.)

Once completed, the GHA’s ‘aircraft incident response plan‘ should be regularly reviewed and maintained – and those required to use it frequently trained (initial and recurrent) and exercised (tested). Associated records and reports should be maintained and retained