Jeff Guzzetti

NTSB Stresses the Importance of Aircraft Maintenance and SMS for Part 91 General Aviation Operators That Fly Paying Passengers

By Jeff Guzzetti

It’s about time.

The NTSB recently held two public Board Meetings to support the notion that preventing maintenance-related accidents is NOT just for the commercial airline industry that fly big jets under FAA’s stringent “Part 121” rules.  Sadly, several recent fatal accidents — all involving paying passengers — of small, propeller or rotor-driven general aviation (GA) aircraft have sullied the reputation of smaller commercial operations conducted under FAA “Part 91” rules. While the NTSB has a long history of concerns about these types of operations, the agency is no longer soft-peddling the issue.

During its meeting on March 26, the NTSB discussed and released their findings for a report entitled: Enhance Safety of Revenue Passenger-Carrying Operations Conducted Under 14 CFR Part 91. ( The largest portion of GA activity consists of pilots flying for their own personal or business purposes in single‑engine airplanes. Passengers on these types of Part 91 flights usually know the pilot, and expectations about safety are based on personal relationships.  However, a wide variety of other GA operations can provide flight services for paying passengers who likely have no knowledge of the level of safety afforded by the pilot or aircraft.

These accidents represent small and diverse segments of GA that transport the public for money, yet are governed only by Part 91 regulations. Why? Because their flight purposes are either exempt from the rules that apply to air carriers or are not covered by any other regulations. These Part 91 operations, which carry thousands of paying passengers each year, are not held to the same maintenance, airworthiness, and operational standards as air carrier, on-demand, and air tour operations conducted under Parts 121, 135, and 136, respectively.  That needs to change.

These “excepted” operations include local commercial air tour flights, sightseeing flights in hot air balloons, parachute jump flights, and “living history” flights conducted aboard historical military aircraft. In addition, some Part 91 commercial operators have exploited these exceptions by carrying people for money for purposes other than the exceptions intended, allowing them to avoid more stringent rules.

The safety issues of Part 91 revenue passenger-carrying operations cited by the NTSB were based on the findings from eight fatal accident investigations between 2010 and 2019, including two recently concluded investigations of accidents in Hawaii and Connecticut:

  • On June 21, 2019, a Beech King Ai,  operated as a Part 91 local parachute jump flight, stalled and crashed after takeoff from Dillingham Airfield in Hawaii. The pilot and 10 passengers were fatally injured. The NTSB determined that the probable cause of this accident was the pilot’s aggressive takeoff maneuver, which resulted in an accelerated stall.  However, they also stated that a significant contributor to the stall was: “the failure … to maintain the airplane in an airworthy condition and to detect and repair the airplane’s twisted left wing, which reduced the airplane’s stall margin.
  • On October 2, 2019, a Boeing B-17G bomber crashed during a precautionary landing at Bradley International Airport in Connecticut following an engine problem. Both pilots and five passengers were killed, while the crew chief and four passengers were seriously injured. The airplane was operated as a Part 91 local sightseeing flight.  The NTSB determined that the probable cause was the pilot’s failure to properly manage the airplane’s configuration and airspeed after he shut down the No. 4 engine following its partial loss of power during the initial climb. However, the board also stated that a contributing factor was the “inadequate maintenance while the airplane was on tour, which resulted in the partial loss of engine power to the Nos. 3 and 4 engines”

Everyone knows that airlines have an extensive safety infrastructure, are subject to stringent safety rules of Parts 121, and receive the highest levels of FAA oversight. However, flights operated under Part 91 are subject to much less stringent pilot training and aircraft maintenance requirements with minimal Federal oversight. The Board expressed the need for greater safety requirements and oversight for these operations, and they issued new recommendations to the FAA to:

  • Develop safety standards or regulations for revenue passenger-carrying operations that are currently conducted under Part 91 including requirements for maintenance.
  • Identify shortcomings in the current regulatory exceptions that would allow revenue passenger-carrying operators to avoid stricter regulations and oversight in operations.

Two weeks later, on April 6, the NTSB met again to finalize its 2021 – 2022 “Most Wanted List of Transportation Safety Improvements.” (  The Most Wanted List is a communication tool through which the NTSB identifies its top safety improvements that — if executed — will prevent accidents. The list covers all modes of transportation, but the primary item for aviation is “Require and Verify the Effectiveness of Safety Management Systems(SMS) in All Revenue Passenger Carrying Aviation Operations.”  

The King Air and B-17G accidents were cited again in the meeting because the NTSB determined that, besides the inadequate maintenance, organizational safety management failures played a role in those accidents. The NTSB stated that widespread adoption of SMS by Part 91 (and Part 135) operators could have a positive safety impact. They also encouraged Part 91 and 135 operators to voluntarily implement such SMS  — while simultaneously urging the FAA to require them – so that the safety of these operations can be improved. SMS was designed to be scalable so that operators could integrate safety management practices tailored to their specific operation.

I recognize that the public likely does not expect small, GA flight operations to have the same level of safety that airlines do; however, it is not unreasonable for the public to expect flights that are, at a minimum, conducted in appropriately maintained aircraft. It’s about time that these smaller operations to stop hiding behind the exceptions whenever they provide flights to the public for money. 

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