What is the due date for making the contribution to a calendar year profit sharing plan sponsored by a tax-exempt entity?

How about date for filing 990 form since allocations must be made by 990 due date in order to count as contributions for such year's 415 limits. For a calendar year plan I think the 990 is due on June 15.

Form 990 is due 4.5 months after year end. May 15 is the due date for a calendar year entity. An extension of 3 months can be requested with another 3 months later; the last date for filing (with approved extensions) would be November 15.

What happens if the contribution is not made by one of the proposed dates?

Why doesn't the plan say when contributions are due?

Then the contribution becomes an allocation for the limitation year in which it is contributed. See Reg. 1.415-6(B)(7)(ii) -contribution must be made by 5 1/2 months after the end of the taxable or fiscal year within which the limitation year ends. Plan does not say when contributions are due because of poor drafting.