Helicopter flying at night can be very dangerous

by Patrick Lafleur, a co-lead of the Rotary Wings Working Group (RWWG). The RWWG is one of the many working groups of the General Aviation Safety Program (GASP), the goal of which is to help the general aviation rotary wings community (i.e. helicopters and gyroplanes) to be safer. If you are interested in joining the RWWG or simply want more information regarding the GASP or the working groups, please contact tc.generalaviation-aviationgenerale.tc@tc.gc.ca.

A helicopter night flying accident occurred in Ontario on March 4, 2019, and I was profoundly affected because it seemed to me that history was repeating itself. Before the Air transportation safety investigation report A19O0026 was released and without knowing the precise causes, a rapid review of the circumstances pointed to a classic scenario: night flight over an unlighted terrain without a visible horizon and with incompatible weather conditions for a night visual flight rules (VFR) flight. This was the latest in a long series of night flying accidents involving private pilots and I think it is necessary to ask serious questions.

Visual flight rules (VFR) flight requires maintaining visual references with the surface. For this, at night, orientation must be maintained by celestial (moon) or artificial lighting (lights on the ground). With an overcast sky or no moon and without sufficient lighting, the horizon is invisible, and it becomes impossible to visually maintain control of the helicopter. These conditions dictate the flight must be conducted with instruments and requires the pilot to be qualified and current, and for the helicopter to be adequately equipped. If not, it is illegal and dangerous to fly in these conditions. The instrument rating requires a thorough ground course, 40 hours of instrument time, a written examination, and a flight test. Pilots must then refresh their skills every six months. Flight conditions must therefore be very good for flying VFR at night.

Instrument flying

From personal experience, I have encountered many pilots who think they would be successful in transitioning from visual flight to their instruments to continue on their way or turn around. The typical helicopter pilot is far from having enough training and experience to make this transition a success. Psychologically, it is very difficult to make the decision to do so. Pilots who manage to cross this barrier have to show a huge amount of concentration to control the very fast roll rate and the yaw caused by the power changes because, by nature, a helicopter is unstable and the controls are very sensitive. Visual perception and sense of balance work together to help us maintain orientation in space. Normally, each movement of the helicopter is perceived visually and corrections are made instinctively. Peripheral vision plays a very important role in this process. We immediately perceive the slightest pitch, roll and yaw and make corrections without even thinking about it. In the absence of external visual references, the pilot has to rely solely on direct vision. He must interpret his instruments one by one by applying the radial scanning technique, which consists of using the artificial horizon or attitude indicator (AI) as a central point. Starting from the AI, he reads another instrument and returns to the AI before moving on to the next instrument, and so on. In all, he must refer to eight different instruments, read the information, interpret it, compare it with other information, and act on the controls to keep a stable attitude. He must rely only on direct vision to control the aircraft because without a visible horizon, peripheral vision is of no use. It is a very difficult process that requires rigorous initial training and regular practice to maintain these skills.

As the pilot strives to maintain a stable flight profile, his senses play tricks on him. Each vertical, longitudinal, and lateral movement acts on his otoliths, the small organs located in the inner ear that help with balance. Without external visual references to compare with, the pilot quickly becomes disoriented until he no longer believes in the instruments. This is called spatial disorientation and when it occurs, studies reveal that you have only 178 seconds to live. I would cut that time in three for the helicopter pilots, who usually fly lower in a less stable aircraft, as shown in this video: 56 Seconds to Live – USHST.

The typical scenario of helicopter loss of control occurs as follows: when visual references are lost, the pilot instinctively stresses on the controls and reduces power. Without peripheral vision, he will not notice the yaw movement. The odds that he will put his eyes on the ball (one of the eight instruments to consult) are slim and he will not compensate on the pedals. This lack of adequate control will cause a turn and his senses will be quickly destabilized. With the helicopter no longer coordinated with the pitot tube offset from the relative wind, the airspeed indicator will show a rapid decrease. The pilot will instinctively push the cyclic forward and rush the helicopter into a fatal dive. To avoid this kind of situation, it is essential to receive good training and practise instrument flying techniques on a regular basis.

Night flying instruction

At the base of any pilot licence and qualification is flight training. I am forced to make a difficult observation here: the teaching of night VFR helicopter rating is insufficient and often sloppy. Standard 421.42(2) of the Canadian Aviation Regulations (CARs) imposes the following requirements:

An applicant for a Canadian night rating shall have acquired in helicopters a minimum of 20 hours of pilot flight time which shall include a minimum of:

• (i) 10 hours of night flight time including a minimum of:
  • (A) 5 hours dual flight time, including 2 hours of cross-country flight time,
  • (B) 5 hours solo flight time, including 10 takeoffs, circuits and landings, and
• (ii) 10 hours dual instrument time.

Historically, this regulation is probably based on the standard of airplane training, which is identical. What is surprising is that no knowledge (theoretical course) is required. The training should include at minimum a ground course on subjects like human factors and pilot decision-making in night flying, VFR/IFR regulations, minimum lighting requirements for helipads, visible horizon, the difficulty of perceiving nighttime weather disturbances, take-off techniques, and departures and approaches in black hole conditions. It should also include a theoretical revision of instrument scanning techniques.

Flight training should include helicopter-specific exercises such as:

• a complete review of instrument flying techniques, including unusual attitude recovery;
• instrument flying at night, including navigation;
• the use of a checklist for night flying adapted to the equipment and type of helicopter used;
• oblique takeoffs to avoid obstacles;
• black hole conditions requiring reference to instruments for maintaining a flat attitude, stable speed and a positive rate of climb;
• safe altitude gain before making a turn;
• stabilized approach in black hole conditions;
• control of interior lighting and systems;
• circuits and manoeuvres at aerodromes offering different ARCAL and lighting systems;
• flight at the edge of a lighted area to show the loss of the visible horizon and the decision-making that is required;
• emergency procedures on a lighted runway;
• a descent over an unlighted terrain (followed by a climb); and
• an autorotation descent (followed by a power recovery and climb) over unlighted ground to demonstrate the risks associated with such manoeuvres.

Obviously, such training should only be given by an instructor with the knowledge and experience to do so. It’s often not the case.

Instructor’s experience

Most helicopter operations are conducted during daytime VFR. The majority of pilots accumulate night flying time very slowly. Many new instructors are young pilots. They’ve accumulated a few hundred hours of daytime flying. Those who are qualified at night can immediately teach it. Without a pre-established curriculum, the instructor and the students burn fuel to build the minimum hours needed by flying around without a specific goal. During initial pilot training, too often, the instructor logs instrument time while other manoeuvres have been practised.

As a result, students end up with fewer instrument hours than expected, which could lead to serious problems in the future. This approach should certainly be reconsidered, perhaps by imposing a minimum night flying experience before an instructor can teach it. Or, perhaps by restricting night flying instruction to Class 3 instructors and only if they are attached to a flight school and have received more training than the minimum standards of the CARs.

Helicopter equipment

Years ago, the stability and command augmentation system (SCAS) and automatic flight control systems (AFCS), commonly referred to as autopilots, were only installed on bigger commercial helicopters that were out of the reach of the individual owner/pilot. As technology has evolved, much lighter and affordable systems have been developed, and helicopter makers are now offering them on most of their models. They incorporate a trim that will generate a force on the controls, permitting the helicopter to maintain a stable attitude. As the name suggests, a stability augmentation system will assist pilots in maintaining the attitude if they lose visual references and give them more time to transition to the instruments. Without such a system, the typical reaction of pilots is to stress and apply too much force on the controls and start overcontrolling, inducing erratic helicopter movements. As explained before, this situation will too often lead to a loss of control with catastrophic consequences.

Obviously, the use of those systems requires knowledge and skills that can only be acquired through proper training and adequate practice. Would it be a good idea to have regulations to render those systems mandatory for night flying?

Pilot decision-making

Better knowledge and more experience make decision-making easier and safer. Pilots trained by inexperienced instructors are all too often faced with complex conditions, and unfortunately do not have the tools to make good decisions. If, on top of that, the pilot is endowed with an impulsive, invulnerable, macho, reckless, or resigned attitude, or a combination of these attitudes, they are definitely at high risk.

A key aspect of night flying decision-making is to obtain available weather information. Unfortunately, several accidents suggest that the pilot did not correctly verify or did not at all verify the weather along his flight route. Or, if he did, he went along anyway, thinking he could adequately face the situation. The Robinson Helicopter Company’s safety notice SN-26 is entitled: “Night flight plus bad weather can be deadly.” That says it all!

Besides having a mechanical problem, all cases of helicopter night flying accidents are the result of bad decisions that were made somewhere along the entire process, starting from initial training to the moment of impact on the surface. It is definitely possible to improve that process to reduce the likelihood of accidents.

The next steps

The industry could develop its own standards to help pilots protect themselves from bad decisions. Better regulation, more rigorous training, and why not financial barriers? Maybe insurers should include strict clauses for night flying. Minimum knowledge and experience, the obligation to perform periodic instrument and night training, and compliance with regulations. Without this, they could withhold payments in case of accidents. Money is often a deterrent. I firmly believe that concerted action by industry stakeholders is possible. By working together, night flying safety could be greatly increased.