Facing a tidal wave of new accounting requirements that are coming on board, a committee of Financial Executives International is appealing to rulemakers to think carefully about when and how a host of new standards will take effect.

Arnold Hanish, chairman of FEI’s Committee on Corporate Reporting and chief accounting officer at Eli Lilly, wrote to the chairmen of the Financial Accounting Standards Board and the International Accounting Standards Board to ask them to consider the big picture as they set effective dates for some substantial new accounting requirements.

Hanish was referring specifically to FASB’s and IASB’s projects on financial statement presentation, leases, pensions, revenue recognition, financial instruments, and liability and equity, all of which are key to the two boards’ efforts to converge U.S. Generally Accepted Accounting Standards with International Financial Reporting Standards.

The boards are acting under a tight timeline to seek convergence on some key areas in the two accounting rulebooks by mid-2011, in part to satisfy the Group of Twenty nations that identified differences in accounting standards as at least a contributing factor to the economic crisis.

Hanish called on FASB and IASB to “deliberate the effective dates and transition of the major convergence standards holistically, rather than on a standard-by-standard basis,” he wrote, to reflect how significant the transition will be for companies adopting the new standards and how interrelated some of the new requirements will be.

In his letter, Hanish described some of the interdependencies among the new requirements that will impact how companies will implement them. New requirements for financial statement presentation, for example, will impact what information must be gathered, which will have an impact on other convergence standards. Likewise, a new definition for a liability will impact what types of assets and liabilities would be accounted for under a new standard for financial instruments, he wrote.

As such, Hanish called on the boards to consider an aggregated effective date for the final converged standards with a three-year implementation period, giving companies the option to adopt early if they’re prepared to do so. “Providing adequate time for the body of converged standards will allow companies to thoughtfully identify the impacts, develop approaches that respond to the change, implement and test solutions, and conduct the necessary training to impacted internal and external individuals specific to their company and industry needs,” he wrote.

FASB and IASB continue to make substantial progress on the core convergence standards, meeting monthly in extensive sessions to reach dozens of preliminary decisions. The boards expect to issue an exposure draft on a new method of financial statement presentation in April 2010.

They’re also identifying areas, however, where they can’t agree and will issue standards that differ. In the financial statement presentation project, for example, FASB plans to require entities to disclose operating assets, liabilities, and cash flows by reportable segment while IASB will not require such a breakdown. IASB meanwhile plans to require the presentation of net debt information as part of the analysis of change and will include minimum line item requirements for the statement of financial position while FASB will not.