Category Archives: General Aviation

A New Year’s Resolution We All Can Make: Prioritize Safety

By Nicholas Worrell, Chief, NTSB Safety Advocacy Division

As 2021 ends, it’s time to reflect on the past 12 months and begin to set goals for the year ahead. After all, as Zig Ziglar once said, “if you aim at nothing, you will hit it every time.” So, let us all aim to improve the safety of our transportation system in 2022.

The NTSB recognizes the need for improvements in all modes of transportation–on the roads, rails, waterways, pipelines, and in the sky. Our 2021–2022 NTSB Most Wanted List of Transportation Safety Improvements (MWL), released in April this year, highlights the transportation safety improvements we believe are needed now to prevent accidents and crashes, reduce injuries, and save lives. We use the list to focus our advocacy efforts and to serve as an important call to action. We ask lawmakers, industry, advocacy, community organizations, and the traveling public to act and champion safety.

As a fellow safety advocate, I ask you to join me in a New Year’s resolution: I pledge to do my part to make transportation safer for all.

To help you take steps to accomplish this resolution, our MWL outlines actions you can take to make transportation safer:

  1. Require and Verify the Effectiveness of Safety Management Systems in all Revenue Passenger-Carrying Aviation Operations
  1. Install Crash-Resistant Recorders and Establish Flight Data Monitoring Programs
  1. Implement a Comprehensive Strategy to Eliminate Speeding-Related Crashes
  1. Protect Vulnerable Road Users through a Safe System Approach 
  1. Prevent Alcohol- and Other Drug-Impaired Driving
  1. Require Collision-Avoidance and Connected-Vehicle Technologies on all Vehicles
  1. Eliminate Distracted Driving
  1. Improve Passenger and Fishing Vessel Safety
  1. Improve Pipeline Leak Detection and Mitigation
  1. Improve Rail Worker Safety

Achieving these improvements is possible; otherwise, they wouldn’t be on our list. The NTSB MWL includes tangible changes and solutions that will, undoubtedly, save lives. But it’s only words on a list if no action is taken. Unlike Times Square on New Year’s Eve, we cannot drop the ball on improvements to transportation safety. The clock is ticking, and the countdown has begun—we can’t afford to waste any more time. Make the resolution to do your part to make transportation safer for all!

In closing, I’d like to thank the transportation safety stakeholders, industry, lawmakers, and advocates we have worked with in 2021 and we look forward to working together in 2022 and beyond.

Accident or Incident? Explaining Aircraft Damage Assessment

By Mike Hodges, Air Safety Investigator, and Clint Crookshanks, Aerospace Engineer (Structures)

When an aircraft crashes, National Transportation Safety Board (NTSB) air safety investigators and aerospace engineers must determine if the event can be classified as an accident or an incident, as defined by Title 49 Code of Federal Regulations (CFR) Part 830.

An accident is:

“…an occurrence associated with the operation of an aircraft which takes place between the time any person boards the aircraft with the intention of flight and all such persons have disembarked, and in which any person suffers death or serious injury, or in which the aircraft receives substantial damage.”

An incident is:

“…an occurrence other than an accident, associated with the operation of an aircraft, which affects or could affect the safety of operations.”

Although the determination of an accident focuses on damage as well as injuries, here we will focus on damage assessment.

So, when assessing the damage, how do we decide what’s an accident and what’s an incident? When we’re first notified about an adverse aircraft event, we begin to assess the aircraft damage. NTSB investigators and engineers attempt to obtain as much information as possible about the damage. Sometimes we’re given information that makes it obvious the aircraft sustained substantial damage, such as the photos showing the extent of the damage (see Figures 1–3). Figures 1-3 show the substantial damage as indicated by the arrows.

Figure 1. A Cessna 170 airplane sustained substantial damage to the left wing, due to ground impact after an aerodynamic stall on takeoff in Arctic Village, Alaska.
Figure 2. An Enstrom F280-F helicopter sustained substantial damage to the tail boom, during a practice run-on landing in Sodus, New York.
Figure 3. A Piper PA-24-250 airplane sustained substantial damage to the left wing, after impacting a light pole during an instrument approach in Sturgis, South Dakota.

Other times, we can’t tell the extent of damage right away and we need to dig deeper. Figures 4- 6 illustrate this scenario and show the substantial damage as indicated by the arrows. For figure 4, additional information surrounding the circumstances of the object impact, a tracked drilling unit, along with the damage sustained to the main rotor blades was obtained from the Federal Aviation Administration (FAA) and the operator. For figure 5, the airplane’s structural repair manual for the damage sustained to the right wing from the bird strike was studied during the damage assessment process. For figure 6, the interior of the fuselage had to be inspected to identify the substantial damage sustained during the hard landing sequence.

Figure 4. A Eurocopter AS 350 B3 helicopter sustained substantial damage to the main rotor blades after impacting a tracked drilling unit in Delta Junction, Alaska.
Figure 5. A Cessna 208B airplane sustained substantial damage to the right wing due to a bird strike in Sacramento, California.
Figure 6. A Beech 1900C airplane sustained substantial damage to the lower aft fuselage after a hard landing in Gambell, Alaska.

When the damage sustained is not obviously substantial, NTSB air safety investigators and aerospace engineers may take additional steps to assess wreckage, such as the following:

  • Working with pilots, operators, mechanics, repair stations, FAA Flight Standards District Offices, aviation insurance adjustors, and aircraft recovery companies to obtain additional damage photographs or damage information
  • Consulting the airframe manufacturer’s air safety and engineering departments
  • Obtaining documents, such as the structural repair manual or illustrated parts catalog, from the airframe manufacturer
  • Considering other unique factors that may determine the damage level, such as airframe fire damage or the aircraft being immersed in a body of water
  • Inspecting the area in question (such as spars in wings, structural areas behind firewalls, driveshafts in helicopters, gearboxes in helicopters, etc.) once the aircraft is recovered
  • Removing components, panels, or skin and using tools to access hard-to-view areas (such as mirrors or electronic borescopes)

We would also determine:

  • if the damaged area is classified as a primary structure (primary structure is defined by the FAA as that structure which carries flight, ground, or pressurization loads, and whose failure would reduce the structural integrity)
  • what repairs are required
  • which components will be replaced to repair the damaged area
  • if the aircraft’s performance or flight characteristics were affected

(The cost or feasibility of repairing an aircraft, as determined by an aircraft insurance company, will not be considered when determining whether an aircraft has sustained substantial damage.)

The damage assessment timeline can vary, depending on how obvious the damage is initially. We might make a substantial determination in a few hours, or, if additional information is needed, the damage assessment can take several weeks. If the aircraft needs to be recovered from a remote area to obtain additional information, the damage assessment could extend even longer.

Although the FAA is always a party member to our investigations, the NTSB is the final authority for determining a damage classification. For those that are involved in an adverse aircraft event, some basic knowledge can help during the assessment, such as:

  • Understanding the definitions and reporting requirements in 49 CFR Part 830
  • Knowing how to directly contact the NTSB
  • Having multiple, high-quality, high-definition photographs from all around the aircraft, showing the aircraft in its entirety
  • Having multiple, high-quality, high-definition photographs of the damaged areas, including close-ups
  • Knowing what repairs are required to the damaged area, along with what components will be replaced to repair the damage (when possible)

Being involved in an accident or incident, regardless of the outcome, is stressful for those involved. The NTSB works diligently with various stakeholders to provide as many answers regarding the damage classification as possible, whether it is determined to be an accident or an incident.

Get it Right: Addressing the Timeliness of NTSB Investigations

By Acting Chairman Bruce Landsberg

There was once a saying in the news media business to “get it first, get it right, but first get it right.” The NTSB strives to get it right above all, but we recognize that timeliness is essential, too. One of my goals even before joining the Board was to see if aviation crash processing time could be reduced on the less complex events. After all, the whole point of accident investigation is to become educated on what went wrong and get the word out as soon as possible to avoid a similar scenario.

But at the NTSB, it’s not all black and white. I want to take this opportunity to clear up some common misconceptions about how the agency functions and describe our process for those unfamiliar with its intricacies.

Congress requires us to evaluate all aviation accidents in the United States as well as significant accidents in all modes of transportation—rail, pipeline, highway, marine, and hazardous materials (how we determine what’s “significant” is a topic for another blog). Given this mandate, our resources are divided. Out of around 400 NTSB staff, only 45 accident field investigators are assigned to aviation. However, although we are required to investigate every civil aviation accident in the United States, as well as those occurring outside the country when they involve US-made equipment, that doesn’t mean we send an investigator to every crash. Often, it’s sufficient for an investigator to just interview a surviving pilot over the phone. In many cases, the Federal Aviation Administration (FAA) sends someone from its local office to an incident and shares the on-scene data with us.

Sometimes, though, an accident is more complex, and a deeper dive is required. For example, vital electronic data can be extracted from avionics, phones, or tablets that aren’t too damaged. Often that can be done in the field, but some devices must be sent to the NTSB lab in Washington, DC, for more thorough examination. There, our technicians painstakingly recover what they can, but—remember—they’re receiving devices from accident scenes in all the other transportation modes as well. The backlog can get lengthy. The lab must also decipher information from voice recorders (if any), vehicle monitors, onboard and external cameras, and metallurgical specimens, and conduct sound spectrum analysis, among other things, from every mode.

Sometimes, despite hours or days of lab effort, no data survives, which makes determining probable cause much more difficult. That’s why our 2021–2022 Most Wanted List of Transportation Safety Improvements includes “Install Crash-Resistant Recorders and Establish Flight Data Monitoring Programs.” Unbiased and accurate device readouts speed investigations up tremendously compared to relying solely on eyewitnesses, who are far less reliable.

In addition to analyzing all the machine information we can, we also look at the human factors present in an accident. We send toxicology samples to the FAA’s medical lab in Oklahoma City for analysis. Autopsy data must be gathered from local medical examiners, whose schedules don’t always align with ours. In a perfect world all this back-end analysis could be completed quickly, but reality intrudes. Factors such as staffing in other state and local government entities, the sheer number of reports the agency is juggling at a time, and yes, inefficiency, can drag things out. Those situations are not always within NTSB control.

Still, many reports frankly took too long to complete, and the average time to complete reports has increased over the years. Recognizing these delays, in 2019, staff in our Office of Aviation Safety began assessing our report process to see if we could streamline it in any way we can control. The effort produced significant improvements, and the early results are encouraging. From March 2020 to March 2021, about 1,100 investigations were initiated, and about 1,500 were completed. This doesn’t include several hundred foreign investigations in which the NTSB participates every year. This contrasts favorably with the prior year, where from 2019 to March 2020, about 1,320 aviation investigations were initiated, and about 1,150 were completed, not including foreign investigations.

Naturally, everyone wants everything faster. Going forward, the less complex cases we investigate are being scaled to finish in 6 months or so, while the more complicated ones will continue to take longer—sometimes much longer. Although we recognize the importance of timeliness in our investigations, we strive for a level of accuracy that ensures we’ve left no stone unturned.

As we revamp our investigation report process to get accurate information out more quickly, I think the public will appreciate the result. But, like most things, the process is a work in progress. We will never sacrifice precision for speed, but rest assured that we’re taking a hard look to see how we can get lifesaving information out more efficiently. We all look forward to seeing the progress the agency makes as we implement new strategies.

The Safety of ‘Part 135’ Flights—Why Should You Care?

Shaun Williams, Senior Aviation Accident Investigator, and Amy Terrone, Safety Advocate

Ever paid for a helicopter tour over a scenic spot, like the islands of Hawaii or the Grand Canyon? Ever needed an emergency medical flight to a hospital or known someone who has? Ever joined the company CEO on a chartered flight to visit a client, or pitched in with friends to charter an airplane as part of a hunting trip or wedding party?

Part 135 certificated flights—more specifically, commuter and on-demand operations—include a variety of aircraft types and segments, many subject to different requirements. Although Part 135 operations are generally very safe, what you may not know is that these operations aren’t required to have all the same safety systems as commercial airlines. The Federal Aviation Administration (FAA) doesn’t mandate all air medical service, air taxi, or on-demand flights to have safety management systems (SMSs), flight data recorders and systems, and some other key safety critical training practices required of passenger-carrying commercial operations (or “Part 121”).

Unfortunately, our recent accident investigations have highlighted this safety gap. We have investigated too many Part 135 accidents since 2000, resulting in dozens of fatalities, that may have been prevented if operators had implemented important safety processes, whether as a result of FAA regulations or their own initiative. Because of our concerns, the NTSB added “Improve the Safety of Part 135 Aircraft Flight Operations” to our Most Wanted List of transportation safety improvements for 2019–2020.

The number of commercial flights this year has decreased dramatically due to the COVID‑19 pandemic, and there are indications that customers are turning to the Part 135 segment for some of their flying needs. This only increases our concern for the safety of these operations. According to a recent New York Times article, for example, many more travelers are considering Part 135 operations for leisure and business travel due to the limited availability of commercial flights as well as the desire to avoid crowded airports and airplanes.

So, what specific regulations are we asking the FAA to implement that are already required of commercial airliners but not of Part 135 operators? We want the FAA to:  

  • require SMSs—a formal, top-down, organization-wide approach to managing and tracking safety that also helps instill a strong safety culture in operations, and
  • require flight data monitoring programs (FDMs)—that is, use technology that records airplane flight data, then make adjustments based on operational data to improve safety going forward.

Although most executive-style Part 135 jets and turboprop aircraft chartered for business purposes are quite safe and even sometimes operate above and beyond what commercial airlines implement, we have seen a few cases in this segment in recent years that raise concern and prompted the bulk of our recommendations in this area. For example, in November 2015, we investigated an accident involving a chartered business jet, Execuflight flight 1526, that crashed into an apartment building on approach to the Akron Fulton International airport in Akron, Ohio. The flight was carrying seven employees of a Florida-based company, all of whom, as well as the captain and first officer, died. Fortunately, no one on the ground was injured. As an on‑demand flight, Execuflight flight 1526 was operating under Part 135 regulations. Our investigation revealed that the operator did not have a SMS or FDM program, either voluntarily or by regulation, that may have prevented the accident. As a result of this crash, we recommended that the FAA require that Part 135 operators like Execuflight have SMS and FDM programs, just as commercial airlines have had for years.

Image from November 2015 Execuflight crash on approach to the Akron Fulton International airport in Akron, Ohio.

Even if the FAA doesn’t require these programs, Part 135 operators should voluntarily adopt them, scalable to their operations, to ensure the highest level of safety for their aircraft and passengers. But, without regulatory requirements, some operators may not implement these safety policies to ensure that their flights are as safe as possible.

It’s important to remember that aviation in the United States is the safest form of transportation. As a customer, you can play a role in keeping it the safest and in improving the safety of on-demand operations. Before you book a flight, do a bit of research and ask a few questions. The following are a few examples of questions you might ask air charter operators directly or the broker if that’s who made your flight arrangements:

  • Does the operator hold its own FAA Air Carrier Certificate? Request copies.
  • Does the operator have a history of any accidents or recordable incidents?
  • Does the operator have an SMS program?
  • Does the operator use flight data recorders and FDM programs?
  • Does the operator belong to any safety organizations? Do these organizations audit or provide some sort of safety review for their members, which could possibly give an insight into their safety program?

You can visit the websites of organizations such as the Air Charter Safety Foundation and its sister organization, the National Air Transportation Association (NATA) for information on these types of operations. The NATA also fulfills the important role of educating the flying public about illegal charters, an increasing safety concern for the industry and for the NTSB.  The FAA also has a helpful website to identify safe air charter operations and how consumers can identify safe and unsafe operators. Illegal or unlicensed air charter operations—those who avoid FAA regulations and compromise safety for a buck or to meet a customer’s unrealistic demands—pose a serious safety hazard. You should look for charter operators who at least comply with current regulations—if not those that do more, such as have an SMS program in place—and reward them with your business.

By doing a little homework in advance, you can make an informed—and important—decision about boarding a Part 135 flight. You might also be making these flights safer for other passengers by making operators aware that their customers are watching and demanding safer operations.

General Aviation’s Silent Killer in the Sky

By Michelle Watters, MD, PhD, MPH

As the weather gets colder and using your aircraft’s cabin heater becomes more of a necessity than a luxury, there’s no better time to start thinking about a plan for handling carbon monoxide. Commonly called the “silent killer,” carbon monoxide is best known as the cause of household poisonings from oil or gas furnaces, stoves, water heaters, or portable generators or fireplaces. For general aviation pilots, carbon monoxide exposure poses a particularly concerning threat because impairing levels can build quickly in an enclosed cabin, and even nonfatal levels can lead to tragic consequences in flight.

For example, in 2017, a private pilot was flying his newly purchased Varga 2150A airplane on a visual flight rules cross-country flight. After flying for about 80 minutes, the airplane suddenly entered a spiraling descent from cruise flight. Witnesses observed the airplane flying erratically at low altitude before it impacted an open field near Bowling Green, Ohio; they stated that the engine was running until impact. Toxicological testing of the pilot’s blood found 55% carbon monoxide saturation (toxic level is 20 percent).

Image from June 1, 2017, airplane crash near Bowling Green, OH

Carbon Monoxide and the Danger of Exposure

So, what is carbon monoxide and why is it dangerous? Carbon monoxide is a simple chemical formed from the incomplete combustion of carbon-containing compounds, such as aviation fuel. It’s odorless, tasteless, and colorless, so your senses don’t provide much of a warning if you’re exposed! (Although, if you do smell exhaust fumes, always assume they contain carbon monoxide.) Carbon monoxide is harmful to people because it competes with oxygen to bind to hemoglobin, an iron-containing protein in your red blood cells. Not only does it outcompete oxygen—which means there’s less oxygen circulating in your blood—but it prevents the blood from unloading oxygen to the tissues and vital organs that need it—including your brain.

What happens when you’re exposed? At low concentrations, symptoms of exposure are mild and vague, and include headache, nausea, and fatigue. You might think you’re just feeling a bit off that day. As the concentration of carbon monoxide in your blood increases, so does impairment, and you’ll start experiencing dizziness, confusion, and disorientation. For longer exposures or high enough concentration levels in your blood, symptoms can be incapacitating and include unconsciousness, coma, and even death.

In the case of the Varga pilot, exposure to carbon monoxide explains his loss of control—he likely suffered confusion, disorientation, and loss of consciousness. But how was he exposed to carbon monoxide in the first place? Examination of the Varga’s heat exchanger showed that the outside casing had either previously been repaired or had been originally constructed of metals with different properties. About half the casing was discolored and exhibited varying signs of corrosion. Small holes from corrosion were found in the casing material, which provided a means for carbon monoxide to enter the cockpit from the exhaust system.

Internal Combustion Engines and Carbon Monoxide Exposure

Wherever there’s an operating internal combustion engine, carbon monoxide is likely being produced. Many airplanes with internal combustion engines are heated by air warmed from circulating around the exhaust system using a heater shroud. As in the case of the Varga pilot, a defect or leak in the exhaust pipes or muffler can introduce carbon monoxide into the cockpit. Although piston engines produce the highest concentrations of carbon monoxide, exhaust from turbine engines can also cause carbon monoxide poisoning.

Our accident investigations show that there are one or two fatal or serious aircraft accidents each year in which carbon monoxide is a finding, contributing factor, or probable cause. Although these accidents are more prevalent in colder months, carbon-monoxide-related accidents happen throughout the year (for instance, the Varga accident occurred in June).

Maintenance and Inspection Issues

Maintenance logbooks indicated that the Varga’s most recent annual inspection was completed less than a month before the accident, and the logbooks didn’t contain any record of heat exchanger repair or replacement. The heat exchanger’s condition at the time of the accident indicates an insufficient annual inspection.

A Federal Aviation Administration (FAA) report found that inadequate maintenance and inspection has contributed to many carbon-monoxide–related accidents. Deficiencies included poor welds, unapproved modifications, and missed holes or cracks on visual inspection. The FAA also found that, for carbon-monoxide–related accidents involving mufflers, there was a strong relationship between the muffler’s lifespan and its failure—the mufflers in the majority of these accidents had more than 1,000 hours of use.

Preventing Carbon Monoxide Exposure

So, how do you prevent carbon monoxide exposure? The first key step is preventing exposure—make sure to routinely inspect your aircraft’s exhaust system and replace when warranted. During each 100‑hour or annual aircraft inspection, ensure your mechanic thoroughly inspects the exhaust systems, air ducting firewalls, and door and window seals. During preflight inspections, look for cracking at the ends of your muffler and evidence of soot, which might indicate cracking in the muffler. Follow the manufacturer’s recommendations for the lifetime limit on your muffler and schedule for replacement parts.

Even with best efforts, leaks may happen. Secondary prevention involves being alerted to the danger before it becomes a problem. Don’t rely solely on knowing the symptoms of carbon monoxide as your warning system—they’re not specific enough to be recognized as exposure before impairment sets in. You might have heard that your skin, lips, or fingernails turn red when you’re exposed to carbon monoxide, but discoloration only happens sometimes, and only at very high levels of exposure. If you do turn red, you’re probably already too impaired to realize it, and it’s probably too late to recover.

So how can you be alerted to dangerous levels of carbon monoxide? Just like for your home, multiple types of carbon monoxide detectors are available for your aircraft and can be placed on your instrument panel. Detectors that only change color when carbon monoxide reaches a certain level are undesirable. The color change may be subtle in some lighting, and these detectors require that you regularly scan the device. Also, color-change devices need to be replaced regularly, and their useful lives may be shortened by exposure to direct sunlight—there’s often no way to tell when they’ve stopped working. Detectors mounted on the instrument panel with audible alerts or flash notifications provide the best warning. The FAA report mentioned earlier in this article found that electrochemical sensors were most suitable for use in general aviation due to their relatively high accuracy, quick response time, and low power consumption.

The next thing to consider is what you’ll do if your carbon monoxide detector goes off, you feel symptoms, or you suspect carbon monoxide in your aircraft. Unlike other medical emergencies where your crew may be able to assist, carbon monoxide exposure affects everyone on your aircraft. Communicate with air traffic control immediately and tell them you suspect carbon monoxide leak and exposure. When flying to the nearest airfield, descend to the lowest safe altitude, as carbon monoxide binds hemoglobin more readily and strongly at higher altitudes. Turn off the heater. Maximally increase cabin fresh air ventilation, open windows if permissible. Consider supplemental oxygen if it’s safe to use. Once on the ground, seek medical attention and do not continue your flight until the aircraft is inspected and repaired.

The NTSB determined that the probable cause of the Varga aircraft accident was the pilot’s loss of control due to impairment from carbon monoxide poisoning. Contributing to the accident was the corrosion of the heat exchanger and the failure of maintenance personnel to adequately inspect and repair or replace the exchanger during the most recent annual inspection. These factors were all avoidable with a little extra care. Inspect your aircraft. Know the symptoms of carbon monoxide poisoning, but don’t rely on them for warning. Install a carbon monoxide detector. Take immediate action.

Interested in more information?

You can learn more by viewing these NTSB and FAA resources: