The Federal Aviation Administration (FAA) and the National Transportation Safety Board (NTSB) share the goals of promoting aviation safety and preventing aircraft accidents. In the wake of several fatal accidents involving revenue-generating Part 91 flights, the NTSB has urged the FAA to develop more stringent safety standards for companies offering tour, skydiving, air combat and tourist flights.
Specifically, NTSB investigators have discovered a pattern of minimal FAA oversight, insufficient pilot training and maintenance shortfalls when investigating accidents in which people were killed or injured during Part 91 flight operations. This includes the crash of a vintage B-17 operated by the Collings Foundation in 2019 in which seven people were killed. While the FAA exempted the Collings Foundation from Part 135 requirements for revenue-paying passenger flights because it had a safety management system in place, the investigation revealed the operator was never inspected for compliance.
The NTSB has also cited cases of aircraft operators avoiding stricter compliance by using regulatory loopholes. For example, one crash involved a flight operator offering air combat flights in California that misidentified itself as a Part 61 flight school.
To address these serious safety issues, the NTSB has asked the FAA to consider developing a policy that brings revenue-generating Part 91 operators under one national standard, similar to the regulations governing Part 135 operators providing commercial, non-scheduled air charter or taxi flights. For air tour operators, this would include eliminating the current exemption in Part 135 for flights operating within 25 miles of the same airport, as well as requiring safety management systems similar to those required of Part 121 airline operations.
Requiring Part 91 operators to comply with higher maintenance and safety standards necessitates additional oversight by regulators. In the future, this may include enforcement of drug and alcohol testing programs for each employee who performs a safety-sensitive function as is required of Part 135 and Part 121 certificate holders.
What are the important distinctions between Federal Aviation Regulation Part 91 and Part 135 operations? Part 91 provides general operating and flight rules for civil aircraft that are not being paid to carry passengers or cargo (i.e., Part 91 rules are non-commercial). To receive payment for transporting passengers or cargo, an aircraft operator must obtain a commercial certificate from the FAA under Part 135 – which is technically called an “air carrier certificate” and commonly called a “charter certificate.”
Overall, the vast majority of Part 135 certificates are issued for operations of business aircraft. According to data provided by the National Air Transportation Association, most are very small businesses with an average of 37 aviation employees. In addition, 68 percent of Part 135 operators have three or fewer aircraft, and 80 percent have five or fewer aircraft.
Part 135 rules are designed to hold aircraft operators receiving payment for transportation to a higher standard than those providing their own transportation. For example, Part 135 imposes pilot training, flight-duty-time and rest requirements that are not mandated under Part 91, as well as more stringent operational, aircraft maintenance and aircraft equipment requirements.
In some cases, this means that an aircraft operated under Part 91 could take off under conditions of zero visibility, while an aircraft under Part 135 could not. Under Part 91, necessary runway length is determined by the aircraft’s performance limitations, while Part 135 requires an additional 40 percent of runway length. Also, while passenger identification is required under Part 135, this does not apply to Part 91 flights within the U.S.
This raises the serious question of how passengers can determine whether or not an operator has a positive safety record. For example, many part 91 and Part 135 passengers expect the same (or a similar) level of safety as they would on a Part 121 scheduled airline flight. While a person may understand the risk associated with skydiving, he or she may not be aware that the aircraft operates under less stringent safety standards.
While the NTSB’s final recommendations for Part 91 flights will soon be available, the FAA has responded to several of the NTSB’s top recommendations to improve Part 135 operations safety. These action items include, but are not limited to, the following:
- Require all newly hired and transferred pilots flying air tours in Hawaii to receive cue-based weather training for the pertinent island/site prior to initiating flight operations. Conduct initial and recurrent checks to verify the pilot’s knowledge of weather-related decision making pertinent to the assigned area of operation.
- Conduct a review to determine the feasibility of requiring all Part 135 certificate holders to install flight data monitoring systems on their aircraft, including a review of their level of participation in voluntary programs.
- To reduce weather-related accidents involving the Ketchikan, Alaska air tour industry, conduct customized surveillance specifically focused on operator training programs and the manner in which the training is implemented and delivered.
- Evaluate extending the current guidance, regulations and policy that address controlled flight into terrain-avoidance training programs for part 135 helicopter operations to all Part 135 operations.
- Evaluate policy and rulemaking options regarding the implementation of special operating rules for the Ketchikan air tour industry that include en route visual flight rules weather minimums and are more conservative than those specified in part 135.
- Conduct a review and hold meetings to determine the feasibility of applying a safety management system requirement to Part 135 operations in place of the current voluntary program.
- Work in coordination with various working groups/committees to produce solutions to enhance terrain awareness system protections and determine if further standards are necessary.
- Focus on improving voluntary programs implemented by Part 135 operators/certificate holders to reduce controlled flight into terrain accidents, with special emphasis on Alaska and human factors issues.
- Develop a safety alert for Part 135 certificate holders that operate under visual flight rules in mountainous terrain at altitudes below the required clearance of the aircraft’s required terrain avoidance awareness system to ensure pilots are aware of the risks and develop plans to minimize those risks.
Finally, NTSB data indicates that, while Part 121 airline operations maintain the best safety record in civil aviation, the Part 135 on-demand air taxi segment has the next lowest accident rate. These are followed by Part 91 jet and Part 135 on-demand turboprop operations, with the Part 91 turboprop category holding the worst safety record. In light of these facts, the discussion of whether Part 91 operators should be held to a higher safety standard merits careful discussion and consideration.
Curt Castagna, president and CEO of Aeroplex/Aerolease Group, is a member of the Los Angeles County Airport Commission, president of the Van Nuys and Long Beach Airport Associations, and immediate past chair of the board of directors for the National Air Transportation Association. A certified private and instrument-rated pilot, he has instructed courses in aviation administration at Cal State Los Angeles for over two decades.
