ASRS

The NASA Aviation Safety Reporting System (ASRS), established in 1976, is a safety reporting program that centralizes and standardizes aviation safety reporting from all areas of aviation. These areas include air traffic control (ATC), flight training, and 14 CFR Parts 91, 121, 133, and 135. Safety reports can be submitted by pilots, ATC, dispatchers, fixed base operators (FBOs), and maintenance personnel. The objective of the NASA ASRS is to identify safety issues across aviation and provide data to address these issues while lessening the likelihood of an accident.

NASA ASRS is one of the largest repositories of safety reports, with tens of thousands of people across aviation using the ASRS to report all matter of safety concerns. The NASA ASRS is, importantly, separate from the Federal Aviation Administration (FAA), who is responsible for enforcing the rules and regulations. This intentional distance allows pilots to submit safety concerns anonymously without fear of discipline. Additionally, the ASRS grants immunity from certain FAA disciplinary actions provided the pilot submitted a report within a set time period and did not intentionally disregard the regulations. It’s worth noting that the ASRS does not offer any protection to those individuals who willfully and/or intentionally violate the rules and regulations. To date, the ASRS has received more than 1.5 million reports. In terms of activity, the ASRS is one of the largest and most well-known safety reporting systems.

The focus of the ASRS, as its name implies, is safety reporting rather than simply keeping a record of accidents and incidents. Therefore, we classify them as events. These events are analyzed to help prevent accidents from occurring while helping guide regulators, manufacturers, and safety providers to adopt or modify policies and regulations to enhance safety. VFR into IMC events are among those tracked by NASA and, provided certain criteria are met, are analyzed and published in the public database.

VFR into IMC Events

Unlike scheduled airline service (14 CFR Part 121), general aviation (GA) pilots are allowed more freedom on departure and arrival weather conditions. While overall, GA benefits from the lack of regulatory oversight, the probability of a weather-related event occurring increases. As such, VFR into IMC is a persistent problem and one that should be largely avoidable.

By the Numbers

From 1995 through 2019, there were 815 ASRS reports involving VFR into IMC events averaging 32 events a year or roughly one every other week. These reports are GA-specific, involving airplanes of all makes and models operating under 14 CFR Parts 91 (non-commercial, general operations, also known as personal or recreational flights), 135, and 137, the latter two referring to commercial operations for hire. Since most light GA operates under Part 91, it’s no surprise that personal flights comprise most events (see Figure 7).

Concerning are the 178 passenger flights—a mix of 14 CFR Parts 91 and 135—where pilots entered these dangerous conditions with the added complication and distraction of passengers. Equally problematic are the 120 training flights that entered these conditions. While some flights were conducted solo and for advanced ratings, initial training was also part of the problem. From a safety standpoint, intentional or unintentional entry into these conditions with a student is bad policy. Consider for instance the law of primacy and its effect on training safe pilots. By allowing students to enter these conditions (on solo flights or with an instructor on board without operating under instrument flight rules), certificated flight instructors (CFIs) are in effect conveying the message that it’s easy to escape from IMC and, therefore, it’s not a major safety concern. While the mere filing of an ASRS report shows that pilots unintentionally or unexpectedly entered VFR into IMC, the driving factors leading to the encounter show a failure to monitor the student or provide quality instruction in favor of time savings.

Certificate Levels

The NTSB data during 2008 to 2020 are comprised mostly of accidents involving private pilots. The ASRS data are also comprised mainly of private pilots (388) followed by commercial (242) and airline transport pilots (ATP) (130), which is proportionate to the type of certificates held by all pilots in the U.S. (see Figure 8). In stark contrast to the NTSB accidents, many reporting pilots held an instrument rating, numbering 461 versus 315 pilots without an instrument rating. Student pilots were in the minority of reports. Since ASRS reports are voluntary, the numbers are not necessarily indicative of higher incidence of occurrence, but a greater likelihood for reporting.

Conditions

Weather and light conditions (see Figures 9 and 10) may have played a significant role in the event outcomes. Given that most GA pilots fly during the day, daylight conditions (606) comprise most reports followed by night with 104, representing roughly 12 percent of reports, similar to NTSB accidents. VMC ranked lowest among the known conditions with mixed conditions leading with 254 reports. IMC was second with 249 reports, followed by marginal at 179. Unlike accident pilots, these pilots were able to extricate themselves from the weather before falling victim.

Case Studies

These reports provide a unique perspective on how quickly pilots need to react to avoid an accident. A review of some meaningful ASRS reports tells how bad decisions led to outcomes necessitating filing a report. Several reports indicate the desire of pilots to push through weather when conditions worsened. One such report details a lowering ceiling forcing the pilot to fly near treetop level just to maintain visual reference to the ground. Another report details a pilot’s decision to depart Special VFR (14 CFR 91.157) only to encounter IMC 200 to 300 feet agl. Realizing the layer was denser and lower than expected, the pilot secured an IFR clearance to return and land. In this case the pilot’s instrument currency paid off, and the pilot was able to fly and land the aircraft safely. Several ASRS reports highlight the value of instrument ratings where pilots were able to pick up an IFR clearance and exit safely after encountering IMC. But what happens when pilots are not instrument rated is worth further discussion.

In one such case a non-instrument-rated pilot flew toward a field under marginal VFR conditions (MVFR) only to have the field go IFR upon their arrival. The pilot soon encountered 900-foot ceilings and rightfully declared an emergency with the tower. The tower controller provided the necessary assistance to get the aircraft out of the conditions by providing terrain updates. The pilot went on to note that had ATC not been available the outcome would have been different. The next case involves a non-instrument-rated pilot’s decision to continue a descent to stay below a building layer. Eventually the pilot became pinched between the terrain and the cloud deck, and with few options available attempted escape. At this point the pilot entered IMC and the classic accident chain began linking. The accident pilot, quickly realizing he was unable to control the aircraft, attempted to exit the conditions with a 180-degree turn. The non-instrument-rated pilot, however, had only a few hours of instrument training and was unfamiliar with the steepness of the bank angle needed for a standard rate turn in cruise flight. The motion caused by the steep bank quickly overwhelmed the pilot’s senses, causing an onslaught of spatial disorientation. Fearing a complete loss of control, the pilot stopped the turn and initiated a wings-level climb. Battling the onset of disorientation, the pilot was safely able to climb above the relatively shallow cloud layer. Prolonged flight in a deeper layer would have likely resulted in spatial disorientation and loss of control. This final case sums up the dangers of continued flight into worsening conditions and the added dangers that spatial disorientation can bring.

VFR into IMC Accident Case Study

Watch this Accident Case Study to learn more about the fatal consequences of not escaping IMC before it’s too late.