- Task-Competency and Wearing of Helmet Identified as Main Issues in Glassy Water Accident
- Operating Unmanned Aircraft Systems in Canada
- Wind Effects on Idling Rotorcraft
On May 20, 2011, a tragic accident claimed the life of an experienced helicopter pilot engaged in the demanding world of water bucketing operations in support of forest fire suppression. The Bell 212 was in the vicinity of Slave Lake, Alta. During an approach to Lesser Slave Lake to pick up water in calm winds and glassy, mirror-like conditions, the helicopter crashed on its right side into the lake, and was severely damaged. While the pilot had accumulated thousands of hours of flying time, his actual experience in water bucketing operations was less extensive; this lead the Transportation Safety Board of Canada (TSB) to address, in its final report, the issue of task competency versus total flight time for pilots engaged in such operations. In addition, as the pilot had left his helmet in its carrying bag on the back seat, the wearing of the helicopter helmet is identified as a recurring theme. The following article is based on TSB Final Report A11W0070.
History of Flight
The helicopter departed from the Slave Lake Airport, proceeded to the Lesser Slave Lake shoreline near the Canyon Creek hamlet and began water bucketing operations. Water pickups were made near the south shore of the lake and drops were made on a fire approximately 0.8 NM south of the shoreline. On its twelfth pickup, while on short final, the helicopter abruptly descended forward, in a near-level attitude, to within several feet of the water surface. Subsequently, the helicopter climbed to approximately 100 ft above the lake surface and then rolled rapidly to the right and descended vertically into the water.
Within approximately three to four minutes, municipal firefighters in the vicinity entered the water, removed the pilot from the wreckage and administered first aid until emergency medical personnel arrived. However, the pilot succumbed to head injuries as a result of the impact.
The helicopter was certified, equipped, and maintained in accordance with existing regulations and approved procedures. It had no known deficiencies, the weight and centre of gravity were within limits and there was sufficient fuel on board.
Water Pickup Location
In calm wind conditions, water can take on a glassy, mirror-like appearance which significantly reduces a pilot's depth perception. If a pilot does not have adequate visual references when flying over glassy water surfaces, difficulties may be encountered in judging height above water and gauging forward speed. The TSB has investigated numerous occurrences where glassy water was either a causal or contributing factor.
To help ensure adequate visual references to safely manoeuvre a helicopter during a water pickup, it is common practice to make pickups as close to shore as possible. This allows the pilot to use the shoreline and surrounding terrain to help judge height above the water as well as the rate of closure during the approach.
The pilot carried out pickups between 300 ft and 1 050 ft from the shoreline. The investigation examined the water pickups conducted by another pilot. On average, the other pilot's pickup location was between 100 ft and 200 ft from the shoreline. The occurrence pilot had been advised by another company pilot to make his pickups as close to shore as possible due to the smoke and glassy water conditions in order to maximize visual references.
Water Bucketing Operations
The helicopter was configured to carry external loads on a hook mounted on the underside of the helicopter's belly. A 100-ft long line attached to the belly hook was being used with a 350 imperial gal. water bucket. The bucket was 23 ft long when suspended, for a total long line length of approximately 124 ft.
The belly hook can be released either electrically or manually. A button on the cyclic control stick is the primary release. To arm this electrical release, the pilot must select the hook release switch, which is guarded and located in the overhead console. The manual release is designed as a backup in an emergency, if the electric release fails. To activate the manual release, the pilot must take one foot off the anti-torque control pedals and use it to push the release pedal.
Bell 212 Flight Manual Supplement (BHT–212–FMS–3) directs pilots to arm the hook for takeoff, disarm it for in-flight operations (e.g., cruise), and arm it before final approach. Arming the hook prior to takeoff and final approach allows the pilot to quickly release the load should a problem arise during a critical phase of flight. Disarming the hook during cruise reduces the risk of an inadvertent release.
In many cases, dropped loads are the result of pilots accidently triggering the electrical release. As previously established in TSB occurrence A09P0249, many pilots choose to fly with the belly hook electrically disarmed to reduce the risk of an inadvertent load release. The electric release was found in the disarmed position on the occurrence aircraft.
Pilot Competencies for Helicopter Wildfire Operations
After the 2007 Helicopter Association of Canada (HAC) convention, a number of provincial agencies responsible for forest firefighting and the HAC agreed that pilot eligibility for roles in wildfire suppression should be based on a task-competency model rather than relying solely on flight hours. In 2010, the HAC, through its Air Taxi Committee subgroup, the Pilot Qualifications Working Group, developed a document entitled Pilot Competencies for Helicopter Wildfire Operations – Best Practices Training and Evaluation.
Alberta Sustainable Resource Development (ASRD) developed an operating handbook for pilots in 2010 and issued an amended version, the 2011 Pilots Handbook, the following year. The 2011 Pilots Handbook endorses the use of qualifications and training competencies identified in the HAC document Pilot Competencies for Helicopter Wildfire Operations. The operator did apply these standards for its pilot checks at the start of the 2011 season.
Helicopter Crash Location
An examination of the wreckage revealed that the collective was found in the full up position, and all collective connections to the engines were consistent with full power being requested. There was no indication of any system malfunction prior to the occurrence. Damage was consistent with the helicopter landing with a high downward velocity on its right side at impact.
The pilot seat had little structural damage. However, the left side lap belt attachment point had torn loose as a result of the impact. It was also determined that the pilot was not wearing the available shoulder harnesses at the time of impact. These harnesses are designed for use when the pilot is sitting upright in a normal flight position. It is common practice for pilots not to wear the shoulder straps while long-lining because it can hinder upper body movement to the bubble window.
The pilot held a valid Airline Transport Pilot Licence–Helicopter, and had close to 5 000 total flight hours on a variety of helicopter types, including 200 hr on the Bell 212. In April 2011, the pilot passed the company Pilot Proficiency Check (PPC) on the Bell 212 after completing the operator’s training program, which included the HAC-developed Pilot Competencies for Helicopter Wildfire Operations.
While the pilot had significant total flying experience on a variety of helicopter types, his Bell 212 time was relatively low, and he had not done any external load operations with any of his employers in the previous 5 years. Of the approximately 500 hr of external load operations he had accumulated up to 2005, only 20 hr had been recorded as long line work. The TSB further determined that on the Canadian Interagency Forest Fire Centre (CIFFC) Pilot Directory, the pilot had listed 500 hr slinging, 50 hr long lining and 50 hr water bucketing. The TSB was unable to reconcile the discrepancy.
The pilot, who was not wearing a flight helmet, received severe head injuries during the impact sequence. The pilot's flight helmet was found inside its bag at the rear of the helicopter cabin. The pilot was not required by the operator to wear a helmet, nor is there a regulation requiring helicopter pilots to wear head protection.
The second most frequently injured body region in survivable helicopter crashes is the head. According to United States military research, the risk of fatal head injuries can be as high as 6 times greater for helicopter occupants not wearing head protection. The effects of non-fatal head injuries range from momentary confusion and inability to concentrate to full loss of consciousness. Incapacitation can compromise a pilot's ability to escape quickly from a helicopter and assist passengers in an emergency evacuation or survival situation.
Transport Canada (TC) has long recognized the safety benefits of using head protection, including in its 1998 Safety of Air Taxi Operations Task Force (SATOPS) Final Report. TC committed to continue to promote to helicopter pilots the safety benefits of wearing helmets—especially in aerial work operations and flight training units—in its safety newsletters and other promotional materials. An example are the two excellent articles titled “Helicopter Safety Helmets—A Hard S(h)ell” and “Low Usage of Head Protection by Helicopter Pilots” published in Issue 2/2010 of the Aviation Safety Letter.
This helmet was retrieved from an AS350 accident in Atlantic
Region (TSB File A07A0007). The other pilot was not
wearing his helmet and suffered serious head injuries.
In addition, SATOPS recommended that helicopter operators, especially aerial work operators, encourage their pilots to wear helmets, that commercial helicopter pilots wear helmets and that flight training units encourage student helicopter pilots to wear helmets.
The TSB has documented a number of occurrences1 where the use of head protection likely would have reduced or prevented the injuries sustained by the pilot.
The high-profile crash of a Sikorsky S-92 in March 2009 (TSB Final Report A09A0016) demonstrated that despite the well-documented safety benefits and the challenging nature of helicopter flying, a majority of helicopter pilots continue to fly without head protection. Likewise, that investigation found that most Canadian helicopter operators still do not actively promote or require the use of head protection by company pilots.
In recognition of the benefits of head protection, the HAC Board of Directors passed a resolution on June 27, 2011, strongly recommending to its operator-members that they should promote the use of helmets for helicopter flight crew members under all operational circumstances which permit their use. HAC also pointed out, however, that certain pilot/aircraft type configurations may preclude safe helmet use.
The TSB determined that the pilot was conducting water pickups at a considerable distance from shore over glassy water. The glassy water conditions that would have made depth perception difficult were compounded by the lack of visual references due to the distance from shore. The helicopter had not yet come into the hover when the water bucket inadvertently entered the water. This resulted in a violent pull rearward and to the left, causing it to descend and roll to the right. The pilot likely overestimated the helicopter's altitude while on final approach, due to glassy water conditions and a lack of visual references, which led to the water bucket inadvertently entering the water.
The helicopter then descended to within several ft of the water. The pilot's subsequent attempt to recover would have required both hands on the controls, precluding arming the belly hook's electrical release. When the helicopter climbed, it is likely that the combination of the long-line tension, helicopter movement, and high power setting caused the helicopter to roll to the right and descend quickly into the water.
Because the belly hook was electrically disarmed, the pilot's ability to jettison the water bucket was limited. It is possible that the pilot released the belly hook using the manual release located between the pedals using one of his feet or it may have been released on impact. Irrespective of how the hook was released, the helicopter impacted the water before the pilot was able to regain control.
The pilot was not wearing his helmet, which contributed to the severity of his head injuries. Helicopter pilots who fly without a helmet are at a greater risk of incapacitation due to head injuries incurred during ditching or a crash.
The pilot had the basic qualifications required for this type of work, however he had minimal recent experience in external load operations, and the TSB could not reconcile some discrepancies they identified in the pilot’s documented slinging and water-bucketing experience.
In conclusion, despite the fact that he trained for and passed the company PPC—including the upgraded task-competency standard developed by the HAC—the experienced pilot appears to have been caught by a combination of events: glassy water conditions; pick-up point further away from shore, reducing the visual reference field; limited recent operational experience for the task at hand; a potentially life-saving helmet resting on the back seat.
by Karen Tarr, Civil Aviation Inspector, Flight Standards, Standards Branch, Civil Aviation, Transport Canada
What is an Unmanned Aircraft System (UAS)?
Unmanned aircraft are considered aircraft under the Aeronautics Act and are governed by the Canadian Aviation Regulations (CARs). An unmanned aircraft system is a set of configurable elements consisting of an unmanned aircraft, its associated control station(s), the required command and control links and any other elements as may be required, at any point during flight operation. Unmanned aircraft are operated by a pilot that is remote from the aircraft.
There are several different terms for UAS, but they all have the same meaning. While the term used in the CARs is “unmanned air vehicle” (UAV), “unmanned aircraft system” (UAS) is the term that is presently used by the global community. The International Civil Aviation Organization (ICAO) has recently developed the term “remotely piloted aircraft system” (RPAS) and Canada will harmonize with ICAO’s terminology in future.
UAS have a wide range of potential uses which will continue to expand.
Special Flight Operations Certificate
In Canada, the CARs require anyone conducting UAS operations to obtain and comply with the provisions of a Special Flight Operations Certificate (SFOC). Applications for operating certificates are dealt with on a case-by-case basis. Individual assessments of the associated risks have to be conducted for each operation.
The certificate applicant is expected to evaluate the risks associated with the proposed operation and provide risk mitigation measures. Operating certificates are issued once a potential operator demonstrates that the risks associated with the operation of the UAS can be managed to an acceptable level.
The requirement for a SFOC is intended as a means of providing a set of operating conditions that the Minister of Transport deems necessary for safe operation. With unmanned aircraft being so diverse in terms of aircraft performance capabilities, mission requirements, operating environment and complexity of the operation, the conditions outlined in operating certificates vary.
The certificate holder has responsibility to ensure that the UAS operation is conducted in such a way that the safety of persons and property on the ground and other airspace users is not jeopardized. If an operator is found to be in contravention of the CARs and the terms of the SFOC, under the Aeronautics Act, Transport Canada may issue fines for contravening the regulated safety requirements.
SFOCs are being issued for many purposes, including, but not limited to, research and development, flight testing and evaluation, flight training, aerial photography, aerial inspections, demonstration and marketing flights, geophysical data acquisition, meteorological surveying, scientific data collection and crop inspections. UAS have a wide range of potential uses which will continue to expand as the critical technology issues that must be addressed to achieve the goal of safe, routine use of the airspace by unmanned aircraft are resolved.
UAS Program Design Working Group
In 2010, the Canadian Aviation Regulation Advisory Council (CARAC) established the Unmanned Aircraft System Program Design Working Group. The purpose of this group is to make recommendations for amendments to current aviation regulations as well as introduce new regulations and standards for the safe integration of routine UAS operations in Canadian airspace.
In order to accomplish the vast amount of work required, the working group is divided into a main working group and three subgroups. The three subgroups are divided into the following subject areas: people, product and operations and access to airspace. The sequence of the work assigned to the working group will be conducted in four distinct phases of work with each phase of work defining regulatory requirements for larger and more complex operations. Completion of Phase 4 work is expected to occur by 2017.
Phase 1 work is now complete and deliverables were presented to the CARAC Technical
Committee in June 2012. Phase 1 addressed small UAS operations where the maximum takeoff weight of the aircraft is 25 kg or less and the aircraft is operated within line-of-sight under visual flight rules. Phase 2 work is now beginning for small unmanned aircraft operating beyond visual line-of-sight.
Small UAS Operations
Regulatory changes based on the recommendations from the Phase 1 report will not be developed at this time. Rather, the guidance material for processing SFOC applications will be updated to incorporate the Phase 1 recommendations for the operation of small UAS within visual line-of-sight. Therefore, while SFOCs will be required for the foreseeable future, operating certificate approvals should be more predictable and timely as the guidance material for processing applications is updated.
Once the updated guidance material becomes available, UAS operators are encouraged to take proactive steps to ensure that the way they are conducting business aligns with the Phase 1 recommendations. These recommendations include, for example, the aircraft meeting a design standard, the operator establishing ground and flight training programs and establishing and maintaining an operations manual and standard operating procedures.
There remain many key challenges ahead for the safe integration of routine UAS operations, e.g. aircraft and system certification, reliable command and control links, reliable and protected spectrum and the ability for the UAS to sense and avoid other traffic and airborne objects in a manner similar to manned aircraft. Transport Canada will continue to work with the UAS community to develop regulations and address the challenges to UAS integration.
The following text is based on an accident prevention bulletin by the United States Forestry Service and is shared with the Aviation Safety Letter audience for its value in safety promotion.
Discussion: On September 26, 2011, a Eurocopter AS-350BA sustained substantial damage after winds caused the aircraft to lift up and roll over on a ridgeline near Juneau, Alaska, despite the engine operating at idle rpm (NTSB # ANC11LA108). The aircraft had landed on the top edge of a steep slope where winds were forecast to be strong and erratic due to an arriving low pressure system over the area. The National Weather Service (NWS) forecasted the surface winds at 35 to 45 kt, however, NWS hourly observations from three different observation locations indicated maximum velocities ranging from 10 to 29 kt.
In an effort to better understand how this accident occurred, Eurocopter simulated the event with a similar aircraft of the same weight and rotor speed, and other environmental features including surrounding terrain (based on pictures supplied from the accident site), landing surface, and winds. The simulation revealed that the aircraft could be lifted off the ground with a wind speed of as little as 37 mph (32 kt) when the impact angle struck from below the rotor disc. As the relative wind angle moves upward toward a level plane with the rotors, the wind velocity required to lift the aircraft increases.
Research of accident reports from the National Transportation Safety Board (NTSB) discovered a similar incident in December 2008 where a Kaman K-1200 helicopter was upset by wind gusts that fatally injured one ground crew member (NTSB # WPR09LA057). In this particular case, the pilot started the helicopter during light and variable quartering tailwinds of what he estimated to be 15 kt. The NTSB investigation determined the winds at the accident site most likely exceeded the maximum wind allowed with reference to the helicopter's prevailing wind envelope, which resulted in the helicopter lifting to the left and rolling over.
- In both instances, winds were forecast to be erratic and gusty, yet local observations were within the published aircraft limits.
- Both aircraft were operating at idle rotor rpm.
- In one situation, ground crew were in close proximity which ultimately resulted in a fatal blade strike.
- There had been no understanding by either crew of a similar event ever happening and they were not alert for this type of control loss.
- Project Aviation Safety Plans (PASPs) should be shared amongst all aircrew (including the pilot) in order to ensure pertinent safety related information is communicated. This may require extra coordination when dealing with vendors (contracted personnel).
- Avoid ground personnel movement within the area of the rotor arc when starting, shutting down, or at ground idle.
Flight crews are required to:
- know wind limitations for start up and shut down for the make/model operated;
- plan for flight conditions based on current observations AND forecast weather;
- base operating rpm on peak wind conditions and plan for additional fuel requirements as necessary when loitering on the ground;
- be aware of the affects of wind blowing from below the rotor disc and plan the landing site selection accordingly; and
- account for rising terrain in the preflight planning process, as it can generate orographic turbulence and greatly accelerate wind velocity as the air travels over the top.
A look back at past occurrences…
This accident prevention bulletin prompted us to look for past occurrences of helicopters being lifted by a gust of wind in Canada. The following scenarios differ slightly from one another, but it is clear that helicopters running on the ground—whether at flight idle or 100 percent rpm—are at risk from wind gusts. In some of the cases below, the pilot even leaves the aircraft with the engine running and rotors turning, which is rarely a good idea. Here are some examples provided to us by the Transportation Safety Board of Canada (TSB):
On September 4, 1978, the pilot of a Bell 206 landed in British Columbia, let his passengers deplane, and brought the throttle to idle. He then got out to inspect the terrain and a gust of wind caught the blades and overturned the aircraft. (TSB file A78W0098).
On August 20, 1981, a Bell 206 had landed on a rocky ridge in British Columbia to offload a firefighting crew. As the last passenger stepped down from the aircraft, a strong gust of wind rolled the helicopter to the right. The main rotor struck a tree and the helicopter slid, on its side, down the ridge to the bottom of a ravine. At the time, the winds were reported to be gusting to 60 mph. (TSB file A81P0085).
On September 2, 1982, the pilot of a Bell 206 landed into a light wind on a ridge in British Columbia which dropped sharply down several thousand feet to a valley. The main rotor disc extended over the face of the summit. As the stopover was short, the pilot did not shut down the engine, but throttled back to flight idle, applied the collective and cyclic frictions, and left his seat with one foot on the skid; while doing so, he did not retain full control of the cyclic. Suddenly, a strong gust of wind came up the ridge and the aircraft lurched into the air. The helicopter came to rest upright 30 ft away after the main rotor blades had hit the ground, severed the tip of the right skid, and shattered the right bubble windshield. (TSB file A82W0074).
On July 30, 2006, a student pilot in an amateur-built Rotorway Exec 162F was performing engine and dynamic system checks on private property in Alberta. The pilot applied enough collective to become light on the skids to determine torque pedal effectiveness. At that time, a strong gust of wind moved the helicopter laterally resulting in a dynamic rollover to the right. The pilot sustained minor scratches and cuts and the helicopter was substantially damaged.
(TSB file A06W0128).
The next (and last) account comes from a veteran helicopter pilot who witnessed a similar event, leading to the loss of a helicopter after it was left running unattended.
“In the mid-seventies, when I was working as a pilot in Northern Quebec, we lost a company Bell 206B on a landing pad because of this phenomenon. The pilot, “Joe”, was an experienced young lad who landed that day on a plywood pad on a small rise along the bank of a river. He landed on the pad facing a southerly direction, with the tail of the helicopter out over the river bank. It is possible that the rear of the skids may not have been in full contact with the pad, but that remains unknown to this day. As we all know, the B206 footprint is weight-biased directly below the mast, toward the rear of the skids. This can result in a nasty trap for the unwary if the rear of the skids are not in full contact with the supporting surface, and this may have been a contributing factor in this accident.
After landing, the passengers disembarked and the pilot realized that there was a package that needed to be offloaded from the cargo compartment which was located on the opposite side of the aircraft from the pilot’s position. The passengers had left, and Joe couldn’t get anyone’s attention. He was in a hurry to get going and retrieve other workers from the bush, but rather than making a radio call for assistance, he tightened the frictions and turned the hydraulics off. He left the throttle in the flight position to facilitate a rapid departure. He jumped out, intending to run around the aircraft to open the cargo compartment and simply drop the package on the helipad. The aircraft was now unoccupied, running at 100% rpm, and was exposed to a gusting westerly wind (10 kt or so) along the river.
Joe told us that, as he passed the nose of the helicopter, it suddenly rose up, pivoting about the rear skids. He tried to jump on the skid toes to gain control, but he ended up falling to the ground, and was struck by the nose of the aircraft as it went almost vertical and drifted backwards, airborne. He suffered a minor gash to the face. (It could have been a lot worse). The helicopter continued backwards, sinking and striking the tail. It subsequently crashed on the bank of the river, some distance below the plane of the helipad. It immediately caught fire and was totally destroyed.
In my opinion, the initiator was the change in the centre of gravity which shifted aft suddenly when the pilot left the aircraft. This may have been exacerbated by the unevenness of the pad, or the position of the helicopter on the pad. Joe was an experienced pilot, but he may not have placed the aircraft far enough forward on the pad to prevent a rotation about the rear contact point when he climbed out. The actual aircraft position on the pad could not be verified.
The final straw appears to have been the exposure of the helicopter on an elevated pad to a cross wind of some strength. The cumulative effect of these forces appears to have caused this accident. It can be argued that even without the wind factor, a 206 placed too far aft on the helipad might have flipped over anyway. However, Joe reported that the aircraft actually flew a short distance before the tail struck the river bank. The aircraft’s final position down the embankment seems to verify that; otherwise, the helicopter would have ended up immediately behind the pad.
In the end, regardless of the wind conditions, leaving any helicopter with rotors turning and no one at the controls invites disaster from various causes. In this case, the aircraft came to a fiery and dramatic end.”
- Date modified: