While crew resource management (CRM) focuses on pilots operating in crew environments, many of the concepts apply to single pilot operations. Many CRM principles have been successfully applied to single-pilot aircraft and led to the development of single-pilot resource management (SRM). SRM is defined as the art of managing all the resources (both onboard the aircraft and from outside sources) available to a pilot prior to and during flight to ensure a successful flight. SRM includes the concepts of aeronautical decision-making (ADM), risk management, controlled flight into terrain (CFIT) awareness, and situational awareness. SRM training helps the pilot maintain situational awareness by managing automation, associated aircraft control, and navigation tasks. This enables the pilot to accurately assess hazards, manage resulting risk potential, and make good decisions.
SRM helps pilots learn to execute methods of gathering information, analyzing it, and making decisions. Although the flight is coordinated by a single person and not an onboard flightcrew, the use of available resources, such as air traffic control (ATC) and automated flight service stations (AFSS), replicates the principles of CRM.
Recognition of Hazards
As will be seen in the following accident, it is often difficult for the pilot involved to recognize a hazard and understand the risk. How a pilot interprets hazards is an important component of risk assessment. Failure to recognize a hazard becomes a fatal mistake in the following accident involving an experimental airplane.
During a cross-country night flight, an experimental airplane experienced an inflight fire followed by a loss of control. The aircraft hit a building and both the commercial pilot and the private pilot-rated passenger were killed. There were no injuries to anyone on the ground. Night visual meteorological conditions prevailed at the time. The flight departed from its home airport about 20:00. The experimental four-place, four-door, high-wing airplane had a composite fuselage powered by a Lycoming IO-360 engine. The aircraft had logged 94.1 hours.
At the time, the flight was transitioning through Class B airspace and receiving visual flight rules (VFR) advisories from Approach Control. According to the facility transcript, at 20:33:36 the pilot queried the controller about a fire smell and asked if there were fire activity in the marshland below them. The controller indicated in the negative, to which the pilot responded, “We just want know if it’s the airplane that smells or the air.” [Figure 6-1]
Shortly afterward, the pilot was advised of a frequency change, which was acknowledged. At 20:36:06, the pilot checked in with another controller and was given the current altimeter setting. A little more than 1½ minutes later, the controller transmitted that he was not receiving the airplane’s Mode C transponder altitude, to which there was no response from the pilot. All communications with the aircraft were lost.
Radar data indicated that when the pilot queried the controller about a fire, the airplane was at 5,500 feet mean sea level (MSL) heading north. The airplane’s radar track continued northbound until 20:37:13, at which time the last transponder return from the airplane was recorded. The remainder of the radar track (primary targets only) showed the airplane turning right to a heading of east-southeast. At about 20:39:20, the airplane turned further right to a heading of south. The last radar return was received at 20:39:36. Three minutes later, the controllers were notified by police that an airplane had crashed into a building.
One witness reported that the airplane was flying at an altitude of about 500 feet above ground level (AGL) in a southeast direction when it made “a slight right turn, then a slight left turn, then a sharp right turn, then descended in what appeared to be in excess of 30° nose down.” A second witness observed the airplane at an altitude of less than 100 feet AGL “in an excessive nose-down attitude towards the ground.” Both witnesses reported that a large post-impact fire erupted.
The pilot, seated in the right front seat, held a commercial pilot certificate with airplane single- and multi-engine land and instrument ratings. Additionally, he held a flight instructor certificate with airplane single-engine land and instrument airplane ratings. According to Federal Aviation Administration (FAA) records, the pilot had accumulated a total flight time of over 1,400 hours. The passenger, who was seated in the left front seat, held a private pilot certificate with an airplane single-engine land rating. Records indicated the passenger was 6 feet 3 inches tall and weighed 231 pounds. [Figure 6-2]
The airplane was constructed by its manufacturer as a prototype for an experimental amateur-built kit and was issued a special airworthiness certificate in the category of experimental research and development. Material examination of the engine and propeller indicated no pre-accident discrepancies, and all major structures were accounted for. It was not possible to assess control continuity due to impact and subsequent fire.
Upon interview, representatives of the manufacturer indicated that the original pilot (left) seat in the airplane was replaced by the owner about a month prior to the accident with a six-way power seat from an automobile. [Figure 6-3] It was installed to accommodate customer requests for an adjustable seat. This seat incorporated three motors that facilitated the six-way movement of the seat. In its original automotive installation, it was wired using a 30-amp circuit breaker for protection; if any motor failed, the automobile circuit would trip. As installed in the automobile, if the breaker did not trip, the switch itself would fail. The seat was installed in the airplane with a 5-amp circuit breaker, but shortly after installation, it was noted that a larger person in the left seat would trip the circuit breaker and the motors became hot.
Figure 6-3. This pilot simply wanted to be comfortable while flying.
The 5-amp circuit breaker was replaced with a 7-amp circuit breaker to prevent excessive tripping.
The event diagram in Figures 6-4 and 6-5 maps the hazards, risk assessment, and attempts to mitigate this accident.
Figure 6-4. Example of an event diagram mapping hazards, risk assessment, and risk mitigation for the first event.
Figure 6-5. Event diagram for events 2 through 4.
As this accident demonstrates, for the pilot of an experimental aircraft, assessing risk goes beyond the self-assessment illustrated in the IMSAFE method. Hazard identification, risk assessment, and its mitigation starts much earlier. The construction method of manufacture and the materials used impose a certain inherent risk that may not be apparent until an adverse event occurs. Unfortunately, hindsight is of limited value to the aircraft passengers and pilot, but do provide others a better understanding of risk and its insidious nature.
The risk assessment matrix in Figure 6-6 can provide lessons from this accident. The vertical scale relates to the likelihood of something happening, while the horizontal scale indicates impact upon safety of the flight.
Figure 6-6. The installation of non-aviation parts can have a profound effect.
While impact damage precluded the National Transportation Safety Board (NTSB) from determining the cause of the fire for the aircraft involved in this accident, the final report discusses the possibility that one of the motors to the seat overheated and ignited the seat cushion. They attributed this possibility to the circuit breaker issue as well as the past instance of the circuit breaker tripping when a large occupant sat in the seat.
It is probable that the installation of the replacement seat started a chain of events diagramed above that led to a fatal accident. The three hazards associated with the seat are discussed more fully below:
- Effect of weight on the aircraft weight and balance and its downstream performance—a seat with three motors adds significant weight on one side to the aircraft. Even with weight allowances, aircraft performance would be affected.
- Seat materials—the criteria for automobile materials are different from those for materials suitable for use in aircraft. Material coverings certified for aircraft use provide additional safety and are intended to reduce unnecessary exposure to fire. In this accident, the possibility exists that the seat covering on the automotive seat exacerbated the fire.
- Potential for electrical malfunctions, especially overheating—why use a 5-amp and then a 7-amp circuit breaker when a 30-amp circuit breaker was used in the original automotive installation?
Did the pilot in command (PIC) take unnecessary risk? Assuming he or she had no knowledge of the differences between the replacement seat and a normal aircraft seat, he should have questioned the installation of a non-aircraft part. And, examine the PIC’s query to the controller during the flight. He indicated he was not sure if his aircraft were on fire or if something on the ground were on fire. Did he incorrectly assess the information he had been given? Did he assume his aircraft was not on fire? Given the seat’s installation, its propensity to overheat, and the indication of a fire, what should the pilot have done?
In Figure 6-6, the risk matrix relates directly to both the builder of the aircraft and the PIC.
- Builder—the likelihood of an adverse event is minimized when aviation standards are adopted in both the selection of material and components, and their installation. The more closely the standards are followed, the less likely the occurrence of an adverse event. In this case, the likelihood of an adverse event is maximized not only because of the seat installation, but that it represents a potential problem across the construction of the entire aircraft.
- PIC—if he were familiar with the seat installation, the problems it created, and its prior problem of overheating, he failed to assess the likelihood that the source of the smell was a fire in the aircraft and not a fire on the ground. No information is available on how long the occupants of the aircraft smelled the smoke, but there were only four minutes between the radio call requesting information about ground fires and the impact with the building. This left the pilot little time to react to a hazard that metamorphosed into a catastrophe.
Rating the likelihood of an impending problem means a pilot needs to ask key questions. For instance, the PIC of this accident needed to ask the aircraft builder how the addition of this seat affected the aircraft. “If this component fails, what are the consequences or severity of the problems it creates?” Obviously, the installation of this seat produced issues in many areas: the seat cover material, electrical loading, weight and balance, and the impact of the added weight upon aircraft performance. Independently, these factors may not create an catastrophic hazard, but taken collectively, they can create a chain of failures that lead to a fatal accident.
The PIC recognized a fire was in evidence while in flight. Given aviation historical data regarding inflight fires, smoke in the flight deck is considered an emergency. In this case, the controller even eliminated one source as a possibility. He told the pilot no ground fires had been reported. Did the PIC fail to take seriously that the smoke must be from his aircraft? Did this pilot make a poor inflight decision or did he make a poor preflight decision?
This example illustrates how an aircraft that is not constructed to standards places the unaware pilot with an element of risk. In 1983, an amateur builder in Alabama used improper wing bolts to secure his homebuilt’s wings. The manufacturer called for the use of eight special close-tolerance high-strength bolts that cost approximately 40 dollars each. The homebuilder found what he decided were the same bolts at his local farm supply center for less than 2 dollars each. Upon takeoff, the bolts sheared at about 15 feet in altitude. Consequently, the aircraft’s wings collapsed, causing permanent disability to the pilot as a result of his injuries. The bolts he used were simple, low-strength material bolts used for wooden gates.
