Maintenance and Operation of Aircraft and Engines 6 3.2 Alterations, Modifications and Additions 3.3 Event of Loss 9 3.4 Insurance 10 3.5 Location of Aircraft 3.6 Application of Insurance Proceeds 3.7 Liens on Mortgaged Property; Taxes 12 3.8 Further Assurances 13 3.9 Recording and Filing 13 3.1