Description

Certain business jets are certified for single-pilot operations, as are most turboprop aircraft used in business aviation. To receive this certification, a manufacturer must demonstrate that one pilot can reach all controls and switches, and that the aircraft systems and design facilitate a workload that one pilot can manage. This article seeks to provide background on single-pilot business aircraft operations, and to examine risk management strategies.

Background

In the United States, the first jet to receive approval for single-pilot operations was the Cessna Citation 1/SP in 1977. Since that time, a number of other aircraft have received such certification. They include the Cirrus Vision Jet SF50, the HondaJet Elite II, the Embraer Phenom 300E, the Pilatus PC-24, and others.

Single-pilot operations in complex aircraft stand in contrast to airline operations, which as of this writing, still require two-pilot cockpits. It must be acknowledged that single-pilot cockpits cannot benefit from the safety defence of one pilot catching another pilot's mistake. Common examples of that include pilots correcting each other's readback errors, faulty altimeter settings, and high or low speeds on approach. The U.S. National Business Aviation Association (NBAA) says single-pilot aircraft are 30 percent more likely to be involved in an accident than aircraft with two pilots.

But at the same time, military aviation has a long history of single-seat fighter jet operations, which involve highly complex, even supersonic aircraft that must not only be flown safely but present the added workload of weapons employment. Single-pilot flight in properly certified aircraft can be accomplished safely by applying adequate risk management. For purposes of this article, we will divide risk management into the following subtopics:

• Threat management 
• Workload management
• Automation management
• Fatigue management
• Aeronautical decision-making

Threat Management

The NBAA's Risk Management Guide for Single-Pilot Light Business Aircraft uses the acronym PAVE to identify the various types of threats.

• Pilot: Am I current, qualified, and proficient in the aircraft? Am I well rested? Am I under stress? Am I sick or on medication? Is there anything else that might degrade my alertness and situational awareness? What errors might I make?
• Aircraft: Are all inspections up to date? Is the aircraft properly equipped for the flight? Does the aircraft have the performance to operate under the expected flight conditions? What maintenance items have been deferred? Once airborne, what malfunctions arise?
• EnVironment: Weather, terrain, airports and airspace, darkness? Will I have to manage a complex non-precision approach late at night at the end of a long duty day?
• External pressures: Is a non-pilot client insisting on getting to an important meeting despite the weather? Am I rushing to get home for a family event? 

Once the threats are identified, the next step is mitigation. The U.S. Federal Aviation Administration's (FAA) Risk Management Handbook lists a number strategies for mitigating risks. They include planning for extra fuel stops, and if possible, selecting a better-equipped aircraft. An example might be choosing an aircraft with a more robust anti-icing system if icing is forecast for the route of flight. Other strategies include circumnavigating the hazard, changing the departure time or date, or even canceling the flight.

If terrain presents challenges, can the pilot plan to arrive and/or depart during visual meteorological conditions, or at least in daylight? Close attention to the Enhanced Ground Proximity Warning System (GPWS), if installed, can mitigate risk during arrivals and departures over rising terrain. If on the ground at a busy airport, a pilot is asked to change the departure runway at the last minute (which would require new performance calculations), is it safest to say, "Unable?" If operating at an unfamiliar and complex airport, should a pilot ask for progressive taxi instructions?

Another consideration is risk: the likelihood of a given threat measured against its severity. NBAA's Risk Management Guide includes a risk assessment matrix in graph form. The likelihoods of threats are classed as probable, occasional, remote, and improbable. The potential severity of encountering those threats are classed as catastrophic, critical, marginal, and negligible.

In that matrix, a probable threat with catastrophic consequences receives a high risk rating, and such a flight should not be conducted. (For example, a flight through a line of thunderstorms.) Conversely, an occasional threat with negligible consequences receives a low risk rating, and such a flight can be conducted safely. (For example, a flight with an en route forecast of light to occasional moderate turbulence.) Flight Risk Assessment Tools like this risk matrix can help pilots judge whether accepting a given risk is justified.

Workload Management

Operating a complex aircraft makes constant cognitive demands on a single pilot, even on low-risk flights. Managing the workload in the most efficient manner becomes critical. In a 2013 study, the FAA's Civil Aerospace Medical Institute, San Jose (U.S.) State University, and the U.S. National Aeronautics and Space Administration (NASA) conducted simulator exercises with 14 Cessna Citation Mustang (C5-10S) pilots. The experimental flights involved two legs under high workloads.

"All participants committed a variety of errors during all four high workload events (e.g., readback error, airspeed violation), but most were not directly related to overall task success," the report said. The report made a number of recommendations for cockpit workload management. Examples include:

• To the extent feasible, pilots should consider completing short, easily performed tasks associated with Air Traffic Control (ATC) clearances quickly, such as dialing in a new heading, while listening to the rest of the clearance.
• Pilots should be prepare to write down or audio-record a clearance involving a reroute or hold and not rely on memory.
• Pilots should complete as many tasks as possible early when anticipating periods of high workload.
• Pilots should use the full range of workload management strategies such as reducing airspeed (with notification to ATC), and asking ATC for assistance (vectors, holding, etc.).
• During periods of automation mode changes (e.g., level off at top of climb) pilots should briefly refrain from other tasks and monitor the automation and aircraft behavior to make sure the aircraft performs as intended.
• When leveling off from a climb or descent, pilots should establish a practice of putting their hands on the thrust levers to make necessary speed adjustments as they monitor automation and aircraft behavior.
• If the autopilot is not in use, the flight director should either be programmed or disengaged to eliminate distracting prompts that do not match those actually being made. (If you aren't using the flight director, turn it off.)
• Pilots should dial in the frequency for an instrument approach to their departure airport prior to departure, in case of an emergency return.
• External memory aids, such as placing an incomplete checklist between the thrust levers, can assist with recalling the need to perform deferred actions.

Automation Management

Closely related to workload management is the subject of automation management. Over the years, automation has greatly increased aircraft safety and capability. Its advantages become especially important in single-pilot operations. However, errors in its use or malfunctions in its operation can lead to an accident or incident. The acronym "CAMI" provides a memory aid for strategies to avoid automation errors:

• Confirm (For example, confirm a clearance to descend from FL300 to FL260.)
• Activate (Dial FL260 into the altitude selector and activate a descent mode.)
• Monitor (Watch for the descent to begin as intended.)
• Intervene (Correct any erroneous inputs if the aircraft does not behave as intended. If necessary, disengage automation and hand fly.)

To remain prepared to intervene, pilots should practice flying with varying levels of automation as workload permits. This should include approaches and landings without the aid of autopilot and autothrottle, when safe to do so. The 2013 study referenced above noted that "poor flying skills were demonstrated when some participants flew manually." The report also said, "It has been demonstrated that after the introduction of highly automated flight systems, transport category aircraft crews were also observed with reduced proficiency in manual flying."

When discussing automation management, we often think mainly of autopilot and flight director functions. However, other automated systems can malfunction or become subject to operator error. Modern pressurization systems work with little pilot input, but pilots should know the system well enough to operate it manually if required. Modern fuel systems lighten pilot workload, but a malfunction can cause a fuel imbalance. Pilots can guard against this with an effective scan. Modern avionics can load flight plans from a database or even from an outside source. But a data transfer error can always occur, so pilots should check every waypoint in a loaded flight plan.

Fatigue Management

The absence of a copilot makes fatigue management all the more important. As stated in Flight Safety Foundation's Fatigue Management Guide for General Aviation Operators of Large and Turbojet Aeroplanes, "Fatigue is now acknowledged as a hazard that predictably degrades various types of human performance and can contribute to aviation accidents or incidents." The publication, prepared in cooperation with the International Civil Aviation Organisation (ICAO) and the International Business Aviation Council (IBAC), also says, "Fatigue is inevitable in a 24/7 industry because the human brain and body function optimally with unrestricted sleep at night. As fatigue cannot be eliminated, it must be managed."

At a minimum, single-pilot business aviation operations must follow the flight time and rest rules under which they are certified. For example, in the United States, flight departments operating under the FAA's Part 135 regulations may not schedule a one-pilot crew for more than eight hours of flying in a 24-hour period. However, flight departments may choose to apply more conservative limits, depending on the conditions in which they operate. As the Fatigue Management Guide points out, a number of operational factors can influence fatigue. They include, but are not limited to:

• The availability of on-board rest facilities (which a single pilot would use between flights)
• Types of flying (long-haul versus short-haul)
• Layover accommodations
• Time spent in ground transportation
• Airport traffic density
• Crew experience levels
• Irregular schedules
• Noise level and other conditions on the flight deck

The Fatigue Management Guide, based on scientific data, points out four key principles:

1. Periods of wake need to be limited. Getting enough sleep on a regular basis is essential for restoring the brain and body.
2. Reducing the amount or the quality of sleep, even for a single night, decreases the ability to function and increases sleepiness the next day.
3. The circadian body clock affects the timing and quality of sleep and produces daily highs and lows in performance capacity on various tasks.
4. Workload can contribute to crew member fatigue. Low workload may unmask physiological sleepiness while high workload may exceed the capability of a fatigued individual.

Based on these key principles, the Fatigue Management guide notes a number of operational implications:

1. For operators providing quick response services, sleep inertia (lack of alertness when someone is suddenly awakened) can pose a significant risk. Mitigation techniques include having dispatch call a pilot to alert him or her, then calling back with mission details. This can help reduce misunderstandings caused by sleep inertia. Extending required response time to allow a pilot of have a cup of coffee has been shown to help alleviate sleep inertia.
2. Uninterrupted sleep cycles are they key to quality sleep, so operators should minimize interruptions. Rest periods should include protected blocks of time in which crew members are not contacted except in emergencies.
3. Caffeine can help. Caffeine takes approximately 30 minutes to take effect and can last for up to 5 hours.
4. During periods of standby, reserve, and on-call duties, operators should minimize interruptions during circadian times when sleep is more likely. Operators should also minimize continuous hours of wakefulness before and during duty periods that are unscheduled, and they should build in some level of schedule predictability.
5. Napping during a duty period, when possible, can help maintain performance.
6. Following a period of restricted sleep, schedules should allow for sleep recovery. The usual recommendation is a minimum of two nights of unrestricted sleep.
7. Insofar as possible, scheduling should consider the circadian body clock. Rotating shifts, night work, and cumulative sleep debt compromise alertness.

Aeronautical Decision-Making (ADM)

The FAA defines aeronautical decision-making as "a systematic approach to the mental process used by aircraft pilots to consistently determine the best course of action in response to a given set of circumstances." A full discussion of ADM goes beyond the scope of this article, but all ADM principles apply to single-pilot resource management (SRM).

In its Risk Management Handbook, the FAA discusses ADM as "analytical" decision-making, as distinct from "naturalistic" decision-making. Analytical decision-making considers the pros and cons of all available solutions and chooses one that adequately mitigates the risk. Naturalistic decision-making relies on more on experience, on what has worked based on previously encountered situations. The challenge for the single pilot is to remain as analytical as possible, without benefit of another pilot on board to offer input. But, depending on the nature of the problem and the workload, a single pilot can solicit input and suggestions from ATC, from dispatchers, and other ground-based resources.

One of the most important parts of ADM is identifying hazardous attitudes that can lead to bad decisions. Without a colleague sitting in the next seat, single pilots must be self-aware enough to know their own minds, and to catch themselves when flawed thinking begins leading them into a trap. The ADM concept defines the following hazardous attitudes:

• Antiauthority: This attitude is found in people who do not like anyone telling them what to do. They may resent having someone tell them what to do and may regard rules, regulations, and procedures as silly or unnecessary.
• Impulsivity: This is the attitude of people who frequently feel the need to do something--anything--immediately. They do not stop to think about what they are about to do, they do not select the best alternative, and they do the first thing that comes to mind.
• Invulnerability: This is the attitude of people who believe accidents are something that happens to other people. "It won't happen to me."
• Macho: Pilots with this attitude will try to prove themselves by taking risks in order to impress others.
• Resignation: The attitude that asks, "What's the use?" Pilots who think this way do not see themselves as able to make a great deal of difference in what happens to them.

FAA Advisory Circular AC 60-22 includes exercises to help pilots identify hazardous attitudes and learn to apply antidotes.