The common law writ of error coram nobis is appropriate remedy where incarceration is due to failure to observe fundamental fairness essential to every concept of justice after sentence has been affirmed on appeal. Mooney v. Holohan, 294 U.S. 103, 55 S.Ct. 340, 79 L.Ed. 791, 98 A.L.R. 406; Pyle v. State of Kansas, 317 U.S. 213, 63 S.Ct. 177, 87 L.Ed. 214; Davis v. State, 200 Ind. 88, 161 N.E. 375; Ex parte Davis, 257 Ala. 520, 60 So.2d 64; Johnson v. Williams, 244 Ala. 391, 13 So.2d 683; Hysler v. State, 146 Fla. 593, 1 So.2d 628. Petition should be granted where it alleges prima facie ground for relief and where supporting affidavits and other evidence show a probability of the truth thereof. Ex parte Burns, 247 Ala. 98, 22 So.2d 517; Chambers v. State, 113 Fla. 786, 152 So. 437; Brown v. State, 32 Ala. App. 500, 27 So.2d 226. When passing on sufficiency of petition court must assume the facts alleged in such petition are true.

A petition for writ of error coram nobis will not be granted and is premature if filed while an appeal is pending. Davis v. State, 257 Ala. 520, 60 So.2d 64 (1952); Brown v. State, 250 Ala. 444, 35 So.2d 518 (1948); Lovell v. State, 344 So.2d 826 (Ala.Cr.App. 1977). II