Safety Issues
Safety Study on VFR Flight into Adverse Weather

74 Accidents occurred to pilots who lost control when the aircraft they were operating VFR was flown into adverse weather conditions. These accidents occur regularly, claiming a disproportionately high number of fatalities each year. They involve professional pilots, private pilots and business pilots who fly general aviation aircraft and chartered commercial aircraft, including fixed-wing aircraft and helicopters.

Although they involved only 352 of the 5,994 accidents recorded between 1976 and 1985 (6% of the total), they accounted for 23% of all fatal accidents and took the lives of 418 persons, or 26% of all fatalities during the ten year period. In other words, VFR-into-IMC accidents have claimed an annual proportion of aviation fatalities that has increased with time.

Areas of interest to the light plane pilot in this section include:

VFR Flight

Here you'll find discussions on such safety issues as:

VFR Weather Minima

Seventy-four accidents occurred to pilots who lost control of the aircraft in reduced forward visibility; 80% of these (59) occurred in uncontrolled airspace, where the visibility minimum is one mile. It is extremely difficult to judge one mile forward visibility from a moving aircraft. In some cases, the accidents occurred in weather conditions which met or exceeded the legal minima. In other cases, it is likely that the pilots had difficulty in accurately determining one mile flight visibility from the moving aircraft, and flew into conditions less than those prescribed by regulation.
A visibility of one mile leaves no margin for error, and permits pilots to fly in weather conditions in which there is inadequate outside reference to ensure consistent aircraft control.

VFR Minima Mountainous Terrain

51% of the Canadian VFR-into-IMC accidents occurred in mountainous or hilly terrain. VFR aircraft often transit the mountains through narrow valleys, where they may be subjected to strong winds and severe turbulence. Weather conditions which are highly changeable due to local effects, and variations in topography combine to create areas where VFR flights operate at high risk. Furthermore, the turning radius of many aircraft is increased at the higher altitudes at which they often operate through mountainous terrain.

Special VFR

This study found only six accidents involving SVFR operations. Four of the six occurred during daylight, four occurred when forward flight visibilities were reduced (as opposed to two in which the pilots flew into cloud) and four of them occurred after the pilots lost control of the aircraft. But
Canadian regulations make no distinction between day and night SVFR. The American and British regulations, restricting night SVFR to specially qualified pilots flying aircraft equipped for IFR flight, take account of the additional risk of operating in poor weather in low-light or no-light conditions.

Food for thought...

VFR-Over-The-Top

Two hundred sixty-six of the accidents (80%) occurred in the enroute phase of flight. The options available to the pilots who encountered the first indications of impending inclement weather included: continuing flight in the adverse conditions in the belief that conditions would improve; conducting a 180 degree turn; or "ducking under" and proceeding around obstacles and inclement weather with the intention of reversing course if conditions deteriorated further. The latter practice, commonly termed 'scud-running', has resulted in pilots regularly operating in weather conditions which jeopardize safe flight.

Night VFR

Which concluded that accidents occurring in other than daylight conditions comprised a disproportionately large number of VFR-into-IMC accidents. Approximately 10% of all Canadian accidents occur during the hours of darkness, which parallels estimates of the general level of night flying activity (also 10%). However, VFR-into-IMC accidents occurring during the hours of darkness accounted for almost 30% of the total study accidents.

This section looks into such factors as:

Night VFR Weather Minima

The high proportion of fatal night accidents attributable to adverse weather is in part the consequence of pilots initiating flight in weather conditions which are legally acceptable, but which deteriorate. The first indication to the night-flying pilot can be the inadvertent entry into IMC.

Night Endorsements

Twenty-four studied accidents which occurred at night resulted from a loss of aircraft control, often after the apparent onset of vertigo. To understand the circumstances of such occurrences, the training, experience and skills of the accident pilots were examined. The accident pilots had seldom obtained additional instrument training after acquiring the minimum experience for night endorsement.

Night Weather Briefing

In light conditions in which hazardous weather conditions can not be detected until they have been encountered, it is essential that pilots have appropriate information before initiating flight. Seventeen accidents that occurred in other-than-daylight conditions involved pilots who did not use available weather briefing facilities.
Licensing, Training & Experience

Examination of the accident data identified a large number which occurred en route to relatively inexperienced pilots, and a disproportionately high number which occurred to flying/school aircraft in B.C.

Conclusions

Accidents involving continued VFR-into-IMC account for a disproportionate number of fatalities each year. The causes and contributing factors to these accidents have recurring themes. These include inappropriate pilot qualifications or proficiency for the conditions encountered, and serious shortcomings in the permissible weather minima for VFR flight, in pilot training, and in pilot licence privileges. In some cases, current industry practices and limitations in aircraft equipment and weather briefing facilities exacerbated the circumstances leading up to the accidents. Since the phenomenon is not limited to any particular sector of the aviation community, diverse action ... will go a long way towards redressing the pervasive conditions leading to this type of accident which annually claims so many fatalities.

(Note: Many of the conclusions mentioned in this final section have now been addressed.)

Safety Issues
Safety Study on Post-Impact Fires Resulting from Small-Aircraft Accidents

For aircraft with a maximum certified take-off weight of 5700 kilograms (12 566 pounds) or less, post-impact fire (PIF) contributes significantly to injuries and fatalities in accidents that are otherwise potentially survivable.

The TSB mounted a major study into this critical safety concern and gathered the following information:

Results

In all 128 accidents in which PIF contributed to serious injuries or fatalities, the aircraft occupants were in close proximity to fire or smoke for some time following the impact. The investigation identified four conditions that were essential for this to occur.

• There was an ignition source in proximity to a combustible material, such as fuel.
• There was combustible material in close proximity to the occupants.
• Occupant egress was compromised.
• The fire was not suppressed in time to prevent fire-related injuries or fatalities.

The data collected and analysed indicate that there is a significant risk for PIF with fire-related injuries and fatalities in small-aircraft accidents. Furthermore, information examined shows that past attempts to change certification requirements have been unsuccessful, largely because of insufficient data, which resulted in cost-benefit analysis conclusions that negated the proposed safety action.

Conclusions

The defences to prevent PIF and to reduce fire-related injuries should fire occur in otherwise survivable accidents involving light aircraft can and should be improved. PIF presents a great risk to the occupants of small aircraft because of

• the high volatility of aviation fuel;
• the close proximity of fuel to occupants;
• the limited escape time;
• the limited energy-absorption characteristics of small-aircraft airframes in crash conditions;
• the high propensity for immobilizing injuries; and
• the inability of airport firefighters and emergency response personnel to suppress PIFs in sufficient time to prevent fire-related injuries and fatalities.

Volatile liquid fuel is the combustible material of greatest significance in PIF accidents. Considering the propensity for rapid propagation and the catastrophic consequences of fuel-fed PIF, the most effective defence against PIF is to prevent the fire from occurring at impact, either by containing fuel or preventing ignition, or both.

Engineering countermeasures in existing small aeroplanes, existing small helicopters, amateur-built aircraft, and basic and advanced ultralights would reduce the incidence of fire-related serious injuries and fatalities in otherwise survivable accidents, and could significantly increase the rate of occupant survival.

Safety Issues
Safety Study of Piloting Skills, Abilities and Knowledge in Seaplane Operations

Seaplanes account for 19% of the Canadian aircraft fleet and 18% of the total number of accidents. However, in most parts of Canada, seaplanes operate only about six months of the year. Thus, the number of seaplane accidents would appear to be disproportionately high.

It is also observed that aeroplanes which are most frequently float equipped, such as Piper Cub "derivatives" (J3, PA11, PA12, PA14, PA18, PA20, PA22), Cessna 172, Cessna 180, Cessna 206, Beaver, and Otter, have more fatal accidents on floats than on wheels. When these aeroplanes are on wheels, 10% of the accidents are fatal, but when on floats, 17% are fatal.

As a result of these disturbing numbers, the TSB undertook an intensive investigation into the seaplane accident record, identifying safety deficiencies associated with the levels of skills, knowledge, and decision-making abilities of pilots engaged in seaplane operations.
The study first describes the characteristics of seaplane accidents which differentiate them from other aeroplane accidents. It then considers the factors which have contributed to these accidents and examines the training and background of the pilots involved. Finally, the report describes the safety deficiencies identified and proposes safety actions to correct them.

The Accidents

The study broke accidents down into two categories, with major injury or fatal accidents being designated as "Serious Accidents."

Phase of Flight

En route accidents account for a little less than a quarter of all accidents, but for more than a third of the serious accidents. However, this study focuses on those aspects of seaplane operations which differentiate them from other flying operations.

Standing & Taxiing

During the standing and taxiing phase, most accidents involved losses of control, propeller contacts, nose down/over, and collisions. As far as serious accidents are concerned, 15 resulted from propeller contact, 3 from nose down/over, and 2 from loss of control.

Take Off

The most frequent types of serious accidents during take-off were loss of control in flight (47 accidents), engine failure (31 accidents), and collision with objects (16 accidents). Loss of control on the water surface and dragged wing were also frequent on take-off, but seldom resulted in serious or fatal injuries.
Approach & Landing

Although hard landings were the most frequent types of accident, loss of control in flight resulted in the largest number of serious accidents (15). Collisions with objects resulted in 12 serious accidents and nose down/over on the surface resulted in 11 serious accidents.

Contributing Factors

Loss of Control on the Water During Take-off

The majority of factors are related to the wind, (improper wind compensation, unfavourable wind, sudden wind shift, rough water), and suggest a lack of proper technique in dealing with various wind conditions. A seaplane is affected much more by wind during landing and take-off on water than is a landplane as there are no brakes and no nose or tail-wheel steering.

Lakes are frequently surrounded by hills which can cause unpredictable shifts in wind speed and direction. On rough water, there is a natural tendency for pilots to pull the aircraft out of the waves as early as possible; however, rough water is often a consequence of strong gusty winds, and a longitudinal oscillation can quickly develop when the aircraft is on the step, causing the aircraft to nose-over.

Loss of Control in Flight During Take-off

Loss of control in flight is either a stall, or a situation in which an aircraft goes out of control and strikes the ground, water or objects.

Factors such as "Failure to maintain flying speed," "Premature lift-off," "Misused flaps," "Improper operation of primary controls," and "Improper wind compensation" are frequently related to poor technique or a lack of skill.

Factors such as "Unsuitable area," "Inadequate pre-flight preparation," and "Failed to follow approved procedures" might demonstrate a lack of knowledge.

Factors such as "Operation beyond ability" and "Failed to abort take-off" can result from poor judgement.

Engine Failure During Take-off

"Water in fuel" ties with "Engine failure for undetermined reason" for number one contributing factor.
On seaplanes, carburettor icing on take-off is a greater risk than on landplanes because of the high level of humidity, due in part to the water-spray on some models, during the take-off run.

Collision With Objects During Take-off

The most frequently indicated factor, "Pilot selected an unsuitable area for take-off," suggests that the pilot exercised poor judgement.

"Inadequate pre-flight preparation," "Failed to abort take-off," and "Operations beyond ability" also reveal behaviours in which poor judgement would have been a factor.

Loss of Control in Flight During Approach

These accidents were generally characterized by a stall, or a stall followed by a spin at low altitude, while turning from base leg to final. Many of the visual cues and approach aids that are available to land-based aircraft are not there for seaplanes about to land on the water, and mountainous or hilly terrain on the final approach may alter the pilot's perception of the correct approach angle.

In the absence of a clearly defined and visible landing area, the turn from base to final can be easily misjudged and result in excessive angles of bank during a critical manoeuvre for landing. The illusions created by the topography and drift at low altitude can also contribute to approach accidents.

Loss of Control on the Water During Landing

The majority of "loss of control accidents occurring during landing on water" happened in cross-wind or glassy-water conditions.

A balked glassy-water landing frequently entails a loss of control. If the flare is too high, the aircraft stalls and the nose or one wing drops. If there is no flare, and with the slightest yaw and/or pitch down, the front end of one float hits the water first and creates an immediate and violent unbalance. In a stalled, nose-down condition, the aircraft usually noses over.

Pilot Factors

While commercial and private pilots are spread fairly evenly in the case of collisions with objects and loss of control during take-off, it can be observed that, in accidents caused by loss of control during landing and engine failures during take-off, more private pilots were involved.

As expected, pilots in the zero to 100-hour category assume the largest share of accidents. However, this is more so in the case of seaplane accidents than landplane accidents.

The Operating and Regulatory Environment

This section takes an in-depth look at factors such as, Attitudes Towards Safety, Training and Certification Requirements, Trainers' Qualifications, Learning and Decision Making, Proficiency, and Periodic Flight Review.

Summary

The report concludes that Seaplane operations are carried out in an unforgiving environment that requires special skills, knowledge, and decision-making abilities. And as Seaplanes are usually operated in remote areas, a distinct culture about their operations has evolved largely unchecked over the years. Consequently, seaplane pilots tend to acquire skills and knowledge through trial and error, peer example, and hearsay - not the most appropriate way to develop the required abilities.

Conclusions

The incidence and severity of seaplane accidents is disproportionately high in comparison to landplanes. Loss of control during take-off, engine failure after take-off, collision with objects during take-off, and loss of control during approach and landing are the most frequent types of accident resulting in serious injuries or fatalities.

The most frequently cited contributing factors in these accidents strongly indicate serious shortcomings in pilot knowledge, skills or techniques, and/or judgement in decision-making.
In sum, the evidence calls into question the adequacy of current practices and requirements for initial and recurrent training from water.

Recommendations

The report ends with recommendations on a variety of topics such as, Training, Trainers' Qualifications, Evaluation and Certification, Flying Currency for Passenger Operations, Periodic Flight Review, and Seaplane Pilots' Seminars.