I was surprised not to see it under 91.203 but after doing some research I found your answer.
(21.5) [Not in FAR/AIM]
(b) The Airplane or Rotorcraft Flight Manual required by paragraph (a) of this section must contain the following information:
(1) The operating limitations and information required to be furnished in an Airplane or Rotorcraft Flight Manual or in manual material, markings, and placards, by the applicable regulations under which the airplane or rotorcraft was type certificated.
(91.9)
(b) No person may operate a U.S.-registered civil aircraft--
(1) For which an Airplane or Rotorcraft Flight Manual is required by Sec. 21.5 of this chapter unless there is available in the aircraft a current, approved Airplane or Rotorcraft Flight Manual or the manual provided for in Sec. 121.141(b); and
By the way, here is a good guide made by the Orlando FSDO about airworthiness...
http://www.faa.gov/about/office_org/...dia/docchk.pdf