Subchapter 9.1 – Communication Failure Under IFR

Navigation under radio failure:

If you were on a published SID or approach procedure, continue along that procedure.
If on radar vectors, maintain the last assigned heading until you reach a fix you can identify (VOR, DME, NDB).
Monitor your navigation aids (VOR, ILS, NDB) continuously. With communication loss, your situational awareness is entirely dependent on your instruments and ground-based navaids.
Plan a descent at the destination to land in VMC if possible, or execute a published instrument approach.
If you must divert due to fuel or weather, proceed to the nearest suitable aerodrome. Publish your intentions via squawk 7600 by maintaining that code.