WASHINGTON — Federal safety officials want the Federal Aviation Administration to find ways to avoid carbon monoxide poisoning on small planes, the cause of 84 deaths in the past four decades.

On Dec. 17, 2000, the pilot of a single-engine plane was killed en route from Chesterfield, Mo., to Tulsa, Okla., after passing out from inhaling carbon monoxide leaking out of a fractured muffler.

On Jan. 17, 1997, another small plane crashed near Alton, N.H., again because the pilot was incapacitated by carbon monoxide poisoning from an exhaust gas leak. Both the pilot and the passenger were killed.

In a recommendation letter to the FAA released late Thursday, the National Transportation Safety Board said that records since 1964 show 84 deaths and five serious injuries resulted from plane crashes involving carbon monoxide poisoning.

The safety board concluded current inspection methods may not find problems with the exhaust systems of internal combustion engines on small planes.

The NTSB recommended that the FAA evaluate the way exhaust systems on the engines are inspected. The safety board also said it wants the FAA to recommend that exhaust systems be replaced after an appropriate time interval.

The NTSB also wants the FAA to set standards for carbon monoxide detection devices to make sure they “distinctly alert” the pilot if the gas is present. The board also wants a requirement that they be installed on single-engine planes that are vulnerable, including Pipers, Cessnas, Beeches, Aero Commanders, Bellancas, Luscombes, Navions and Aeroncas.