Flying at night presents unique challenges to general aviation pilots, according to a new report from the Aircraft Owners and Pilots Association Air Safety Institute, which notes that “night IMC is highly lethal.”
The Night Flying Accident Analysis Report 2017-2021 looks at the pitfalls of night flight operations while providing a detailed analysis of accident causes and findings.
According to the report, there are four main causes of night flying accidents:
- Loss of control in flight
- Engine and propeller failure
- Fuel related
- Loss of control on the ground
“Night flying introduces challenges that are reflected in the data,” said Robert Geske, AOPA Air Safety Institute manager of aviation safety analysis. “More than one-quarter of fatal night flying accidents occurred because of spatial disorientation, a condition that can bring about loss of control in flight — the leading cause of all night flying accidents.”
During the five years covered in the report, there were 464 fixed-wing general aviation accidents with 150 ending in a fatality, he noted.
“Night accidents account for only 7% of all GA accidents. However, fatal night accidents account for 16% of fatal GA accidents, highlighting the risks associated with night operations.”
Flight Phase
Night accidents occur with the highest frequency during the en route phase of flight (28%) in contrast to daytime GA flights when accidents are more common during the landing phase of flight.
VFR approach is second (12%), followed by initial climb (11%).
Landing, distinctly absent from the top three compared to daytime accidents, is broken into multiple subparts, such as flare and landing roll. All subparts, when combined, only bump landing into second place, according to the report.
Looking at only fatal accidents, the report found that the en route phase (37%) remains the leading accident phase. Initial climb moves to second (17%) followed by maneuvering (13%).
The differences between maneuvering and en route are usually altitude and destination, the report notes. Local flights, typically, put the aircraft in the maneuvering phase. Cross-countries would indicate an en route phase.
“Impact forces drive fatal accident statistics,” the report continues. “Takeoff and landing phases account for minimal fatal accidents. Survivability increases the slower and lower to the ground the aircraft is. Only one landing accident was fatal, and it involved a pilot who attempted to abort the landing after touchdown. In this case, decelerating into the crash is preferable to accelerating into the crash. The challenge is accepting that a crash is imminent.”
Weather Conditions
According to the analysis, 84% of night accidents were in visual meteorological conditions (VMC) and 14% in instrument meteorological conditions (IMC). The remainder are unknown.
Of the 390 VMC accidents, 103 (26%) were fatal.
IMC was far more deadly. More than 67% of accidents were fatal.
“Night IMC is highly lethal,” the report states. “Flights occurring during these conditions warrant additional mitigations.”
Accident Causes
A number of factors contribute to accident outcomes, but the NTSB determines a singular event among these factors — called the defining event — and all accidents have one, according to the report.
A look at the defining events in night flying reveals LOC-I leads accident causes with 78, followed by system component failure powerplant (SCF-PP) with 53 accidents. Fuel-related accounts for 49 accidents. Fourth, and rounding out approximately half of the accidents, is LOC-G with 40 accidents.
LOC-I, which includes stalls and spins, most often occurred during the en route phase (19) followed by VFR approach and initial climb phases (both 16). IFR approach and maneuvering tied at eight accidents each.
Extracting fatal LOC-I accidents, the en route phase of flight leads with the most accidents (18) and highest lethality — a measure of total accidents to fatal accidents — at 95%. Initial climb was second (12) followed by VFR approach (8). The main LOC-I accident cause was stall/spin (20).
SCF-PP is best thought of as engine and/or propeller failure. Causes listed may include additional factors outside of the pilot’s control, for example, mistakes made by maintenance providers.
SCF-PP accidents occur most often during the en route phase (30). Initial climb (9) and VFR approach (4) rank second and third.
Looking at fatal accidents only, SCF-PP shifts from the second-highest cause of accidents to the seventh highest cause. This shift provides evidence that powerplant failures are largely survivable, the report notes.
“Pilots who become distracted or fixated on the issue instead of managing the problem increase their risk of fatality,” it continues.
Only seven of the 53 accidents were the result of maintenance errors. Pilots’ failure to identify problems during preflight was a theme in SCF-PP accidents as well.
Fuel-related events include exhaustion, starvation/mismanagement, contamination, and wrong fuel. In cases where the wrong fuel led to engine failure (e.g., detonation), fuel is the defining event, not SCF-PP.
The No. 1 phase of flight where fuel-related accidents occur is during the en route phase of flight (25), followed by VFR approach (7).
Fuel accidents share similarities with SCF-PP when examining fatal accidents, according to the analysis.
These similarities can be attributed to how the problem presents itself: Fuel issues affect the engine and pilots respond as they would to an engine issue. Only nine fuel-related accidents were fatal.
The leading factor — and unforgivable sin in aviation — for fuel-related accidents was exhaustion (23). Starvation (17) was second, followed by carburetor icing (5).
Exhaustion happens when the aircraft runs out of fuel, in contrast to starvation, which occurs when fuel remains but something — perhaps pilot-related, such as improper fuel system management — prevents the fuel from reaching the engine.
LOC-G differs from LOC-I as all the events take place when the aircraft is on the ground, including takeoff and landing.
Aircraft on the landing roll account for 45% of all LOC-G accidents.
No fatal LOC-G accidents occurred during the five-year period. This is largely attributed to the aircraft being on the ground at low airspeed. These two factors significantly reduce impact forces, the report notes.
Loss of directional control — usually caused by lack of proper rudder and aileron inputs (especially in crosswind conditions) — is a major contributor to LOC-G accidents, the report discovered.
Spatial disorientation got a special call-out in the report, which noted that “pilots flying at night are susceptible to spatial disorientation.”
During the period studied, 41 accidents involved spatial disorientation (8% of all night accidents).
“Astonishingly, 39 of these accidents were fatal, roughly 26% percent of all fatal night accidents,” the report states. “The level of incapacitation from spatial disorientation is misunderstood as something that can easily be overcome. In these cases, pilots rarely survived once succumbing to the overpowering sensation that is spatial disorientation.”
Recommendations
Additional training focused on night operations, risks, and mitigations leads the list of recommendations closing out the report.
“Emphasizing proficiency instead of currency and the importance of routine night flying and flight training for certificated pilots should reduce accidents,” it states.
This training should go beyond takeoffs and landings to the en route phase of flight where most night accidents occur, Air Safety Institute officials said.
As spatial disorientation was a consistent theme in night accidents, training to help pilots understand what conditions cause disorientation, along with better training on recognition and prevention, should reduce the number of accidents.
The FAA offers spatial disorientation training for pilots at its facilities and occasionally at air shows. Encouraging pilots to participate in this training would help them understand their individual responses and how to mitigate them, the reports states.
Loss of control in flight, including stall/spin accidents, was the number one cause of overall and fatal accidents. Providing pilots with night-specific training, incorporating scenario-based objectives specifically focusing on aircraft control, low-speed management, and reaction to startle factors, would help drive down accident rates.
The report notes that while SCF-PP accidents are largely survivable, better identification of impending engine failure could help reduce accidents in this category. The installation of engine monitoring equipment can alert pilots to building or imminent engine issues, providing them time to divert to a suitable landing area.
Better fuel monitoring technology could make pilots aware of exhaustion well ahead of engine shutdown. Encouraging pilots to dip tanks prior to each flight, as well as taking extra fuel when conditions permit, would also reduce accidents.
Instructing pilots on fuel system operations and design, along with verification of fuel transfer, would mitigate starvation accidents.
Other recommendations closing out the report include:
- Improve stick-and-rudder skills, with an emphasis on stall awareness and prevention
- Encourage pilots to fly with flashlights or headlamps to help illuminate dark cockpits
- Encourage the wider adoption of synthetic vision, heads up displays (HUD), and angle of attack indicators
- Pilots should assess their arrival and departure airport environment, light levels, and approach/departure paths for the potential of encountering spatial disorientation.
- CFIs should incorporate a portion of three hours of simulated instrument time, required for private pilots, into night operations training.
You can read the full report at AOPA.org.
There was a time when most of my flying was at night, up, down and across the Rockies. Then came the time I reconsidered the risk. I then sold one of my planes I often used at night, super clean excellent performing single engine. About 5 flight hours after selling it an exhaust valve head snapped and blew a cylinder, wrecking the entire engine. It was over Denver but daytime and within gliding distance to Jeffco. Had it happened to me at night I no doubt wouldn’t have survived.
The up side is I was always over unpopulated areas, even when landing at my destinations. To me flying out places like the LA basin is worse, day or night.