Yellow Aviation is an existing client of PPP Partners. The auditors are aware that the impact of the global financial crisis on airlines has been severe, with predictions of a prolonged downturn. Also, as a result of the crisis along with the entry of new competitors in the domestic and international markets, airlines have been heavily discounting ights. The client's policies include the following: Aircraft maintenance costs policy The standard cost of major airplane and engine maintenance checks is capitalized and depreciated over the shorter of the scheduled usage period to the next major inspection date or the remaining life of the aircraft. Yellow Aviation's latest financial data show the carrying values of aircraft and engines (including major maintenance costs) to be at a similar level to last year, while depreciation expenses have decreased by 7 percent. Required (a) What accounts and assertions may have an elevated level of RMM this year? (b) What procedures could you perform to gather evidence relevant to these assertions