Pilots who have received a heart transplant may subsequently want to resume flying. This study was undertaken to determine whether a group of heart transplant recipients who had a particularly low risk of sudden unexpected death could be identified from clinical data. An event, 'rapid- onset death,' was defined incorporating a number of possible causes of death that could result in a heart transplant recipient-pilot losing control of an airplane. The survival of 3676 patients undergoing a first heart transplantation was 85% and 73% at 1 and 5 years, respectively, the hazard function having a high early phase of risk. When time zero was moved to the beginning of the second year after transplantation, the freedom from 'rapid- onset death' at posttransplantation year 2 and posttransplantation year 5 was 96.8% and 88%, respectively. For patients who had both a 'normal' coronary angiogram and no episodes of acute heart rejection during the first year transplantation, the probability of 'rapid onset death' during the second posttransplantation year was 1.4%, and given the same circumstances, during the third posttransplantation year the risk of 'rapid-onset death' was 1.6%. This information is potentially useful to the Federal Aviation Administration for policy decisions regarding this issue.