Safety Recommendation A-04-028

Location: Guthrie Center, Iowa Accident Number: WPR19FA022 Date & Time: November 9, 2018, 17:15 Registration: N91770 Aircraft: Piper PA28 Aircraft Damage: Substantial Defining Event: Powerplant sys/comp malf/fail Injuries: 4 Fatal Flight Conducted Under: Part 91: General aviation

Analysis

About 45 minutes into the cross-country flight, the student pilot passenger reported to air traffic control that the pilot was having a heart attack and that he was going to take control of the airplane and divert to an airport about 20 miles away; however, another airport was much closer, and controllers received no further communications from the pilot. The student then reported over the nearby airport’s common traffic advisory frequency that he would attempt to divert there. GPS flight track data indicated that, a short time later, the airplane began to fly in an erratic manner, climbing and descending over the area of the diversion airport.

The airplane subsequently collided with terrain in a wings-level attitude.

All four occupants sustained fatal injuries, and toxicology testing indicated that all had high levels of carboxyhemoglobin, which is caused by the inhalation of carbon monoxide (CO), an odorless, tasteless, colorless, nonirritating gas formed by hydrocarbon combustion. Levels in both pilots and one passenger where high enough to have caused confusion, seizures, or loss of consciousness. There was no evidence the pilot had a heart attack, so his symptoms were likely due to the CO poisoning.

The engine was equipped with three identical exhaust mufflers. Examination of the aft muffler revealed a crack that allowed engine exhaust gases to enter the cabin through the cabin heating system.

The muffler’s crack developed as a result of corrosion and thinning of the muffler wall. The crack and small perforations in the muffler wall were likely present at the time of the last inspection, which occurred shortly before the accident; however, due to damage from impact, it could not be determined if the extent of cracking was readily visible at the time of inspection. Also, the crack could have opened just before the accident flight due to an engine backfire that occurred during startup.

Use of a pressure check during an inspection could help identify cracks and small perforations that can be obscured by oxides and deposits during a visual inspection; however, the manufacturer's service manual only recommended a pressure check when a visual inspection could not be accomplished.

The FAA indicated that, as the proper inspection and maintenance of mufflers and exhaust system components is the primary method of preventing CO contamination, installing a CO detector is not necessary to correct an unsafe condition as defined by 14 CFR Part 39. Accordingly, the FAA does not plan to require the installation of such devices in all single-engine reciprocating-powered airplanes with forward-mounted engine and enclosed cockpits, as recommended.

Although SAIB CE-10-19 R1 recommends that owners and operators of these aircraft review the FAA’s technical report and also use a CO detector while operating their aircraft, the NTSB does not believe that issuance of the SAIB alone is satisfactory. Accordingly, because the FAA indicated that its actions in response to this recommendation are complete, Safety Recommendation A-04-28 is classified CLOSED—UNACCEPTABLE ACTION.

CC# 201100035: - From J. Randolph Babbitt, Administrator: FAA report DOI/FAAIAR-09/49 states, "Placing a suitable CO detector at the instrument panel would serve as the secondary prevention method to further prevent CO exposure" and "that CO contamination in the cabin is primarily a consequence of inadequate maintenance and inspection of exhaust systems." We agree that CO detectors provide an additional layer of protection for those who fly on general aviation aircraft. However, the primary prevention method is the proper inspection and maintenance of mufflers and exhaust system components.

Since the lack of a CO detector alone is not unsafe, installing a CO detector is not necessary to correct an unsafe condition as defined by 14 CFR Part 39. However we are promoting the purchase, installation, and use of CO detectors. We published SAIB CE-l 0-19 RI recommending owners and operators of general aviation aircraft consider the information in the technical report and use a CO detector while operating their aircraft. I believe that the FAA has effectively addressed these safety recommendations, and I consider our actions complete.

The NTSB notes that to mandate installation of CO detectors, the FAA must first determine that an unsafe condition exists. Once the FAA’s evaluation is complete, it will determine the resulting action that needs to be taken. Pending completion of the FAA’s evaluation and its taking the recommended action, Safety Recommendation A-04-28 remains classified OPEN -- ACCEPTABLE RESPONSE.

Letter Mail Controlled 5/28/2008 10:53:40 AM MC# 2080270: - From Robert A. Sturgell, Acting Administrator: Through the research described in our response to Safety Recommendation A-04-26, we will pursue engineering guidance for proper installation procedures for carbon monoxide detectors meeting FAA TSO C-48, Carbon Monoxide Detector Instruments. The ongoing research project includes development of a streamlined method of installing carbon monoxide detectors meeting TSO C-48 in general aviation products and possible regulatory considerations for carbon monoxide detectors. The technical report from this research is scheduled to be completed by the end of 2008.

When this research is completed, the FAA will determine if a change to 14 CFR Part 23 is necessary to mandate installation of CO detectors as required equipment on newly designed aircraft. The FAA will also determine the need for airworthiness directive action if an unsafe condition exists with any specific type design in the existing general aviation fleet. I will keep the Board informed of the FAA’s progress on this safety recommendation.

The Safety Board notes that to mandate installation of CO detectors, the FAA must first determine that an unsafe condition exists. The FAA is currently conducting this evaluation and will determine the resulting action that needs to be taken. Pending completion of the FAA's evaluation and the FAA's taking the recommended action, Safety Recommendation A-04-28 is classified OPEN -- ACCEPTABLE RESPONSE.

Letter Mail Controlled 9/16/2004 1:07:32 PM MC# 2040566 - From Marion C. Blakey, Administrator: Mandating installation of carbon monoxide detectors in all single-engine reciprocating-powered airplanes would require either rulemaking or an airworthiness directive. The FAA is conducting an investigation to determine if an unsafe condition exists and what action needs to be implemented. I will inform the Board of the FAA's proposed actions to address these recommendations once the evaluation is completed.