- Declaring an Emergency
- Longline Accidents-Another Perspective
- Use of Incorrect Power-Setting References
- I Chose to Live: A Moving Account by an Air Tragedy Survivor
- Inadequate Cargo Restraint
- The Importance of Proper Weight and Balance
- David Charles Abramson Memorial (DCAM) Flight Instructor Safety Award
by Mark Dixon, Civil Aviation Safety Inspector, General Aviation, Ontario Region, Civil Aviation, Transport Canada
"TOWER, THIS IS HOTEL ECHO LIMA PAPA, WE ARE DECLARING AN EMERGENCY 10MILES OUT, 4PEOPLE ON BOARD, 1 000 POUNDS OF FUEL AND NO HAZARDOUS MATERIALS."
What does it mean to declare an emergency? Is the pilot-incommand (PIC) going to have to face an inquiry? Does the PIC have to pay for emergency services? Does the PIC need permission to do this? Is declaring an emergency a really big inconvenience to air traffic control (ATC) and other aircraft?
This article will look at declaring an emergency from a decision-making standpoint, and shed some light on the why and when to declare an emergency.
First, read the following report taken from the Civil Aviation Daily Occurrence Reporting System (CADORS) and, assuming you were the PIC, make a quick decision if you would declare an emergency or not:
The (a/c type) turbojet aircraft (operating as XXXX) was on an IFR flight from Chicago (O'Hare) International Airport (KORD) to Ottawa MacDonald-Cartier International Airport (CYOW). The flight crew reported that they had a flap problem and requested to land on Runway32. They advised that they were not declaring an emergency and that no emergency equipment would be required. However, NAV CANADA tower staff declared an emergency and the crash crews and airport duty manager were advised. The aircraft landed without incident at 0329Z, and aircraft rescue and firefighting (ARFF) stood down at 0330Z. Operational impact-unknown.
Well, would you or not? Let's look at the situation.
Having declared many emergencies over the years, I feel there is no such thing as a "slight" or "kind of" emergency. It is either an emergency or it is not. To decide if you should declare an emergency depends on the situation. The decision to declare should be made as early as possible, and communicated to ATC right away. Generally speaking, you should never be afraid to declare the emergency. If the situation that you are experiencing is in any way, or could become, unsafe or dangerous, declare the emergency. Humming and hawing, delaying, declaring "kind of an emergency" or a "small emergency" leaves a lot of uncertainty. You owe it to your passengers, crew, and the aircraft owner to declare an emergency if you have a problem that warrants it. ATC will only be able to coordinate emergency resources and help out if they know you have a problem. If they are left out, or uncertain of the degree of the situation, it makes it difficult to help. Emergency services personnel are professionals who will not give you a hard time about declaring the emergency- it's their job, and they are always happy to help. You will not face an inquiry or be liable for fees or fines.
A CADORS report is generated by NAV CANADA and is followed up by Transport Canada or the Transportation Safety Board of Canada (TSB). When contacted, we like to get details and discuss the incident. For all of the CADORS reports that I have followed up, I have told the PIC that declaring an emergency was a good decision, and that we are following up from an "educational safety" point of view.
For the purposes of this newsletter, I ran the above CADORS report by a wide variety of Transport Canada inspectors, private pilots, flight instructors and senior airline check pilots.
Emergency vehicles responding to an aircraft emergency
Not surprisingly, the opinions varied wildly. Some pilots will declare an emergency if their watch stops working within a control zone on a VFR day; others would only declare if three of the four engines were on fire, the first officer was incapacitated while doing an ADF approach to minima, with no electrics, hydraulics, or hand held radio, 10 min of fuel remaining, and no suitable alternate within 1 000 mi. OK, that's an exaggeration, but the feedback clearly makes declaring an emergency a pilot decision-making topic.
The Transport Canada Aeronautical Information Manual (TCAIM) makes several references to emergencies-SAR4.1, COM5.11, and RAC1.8. Go and look up these references, I'll wait while you do this...When an emergency is declared, flight priority is also being requested. It is then up to the pilot to decide if emergency response vehicles (fire, ambulance) are needed on site for the landing. This decision essentially rests with the pilot, although NAV CANADA or the airport authority may also call for emergency response vehicles (as was the case in our CADORS report). Declaring an emergency is not exactly the same as a MAYDAY or PANPAN call; however, they do often come together. A MAYDAY is a situation of distress where safety is being threatened by grave and imminent danger, and requires immediate assistance. A PANPAN call is used in a situation of urgency where safety is threatened, but does not require immediate assistance. To sum up, MAYDAY and PANPAN calls are the communication tools, and declaring an emergency is the request for "flight priority."
Every sound decision requires an assessment of the situation and the various options. Sometimes you have very little time to make a choice. Let's assume time was limited for our crew in the CADORS report; therefore, the best choice in my opinion is the safest one-declare the emergency and get ARFF on site. Taking the high road will generate less second-guessing and doubt from the crew, and allow you to proceed with checklists, standard operating procedures (SOPs), briefings, abnormalities, and ensure everyone is clear on the plan. This should lead to the least risk to passengers, crew, and others. Money concerns should be very low on the consideration pole.
In general aviation, the need to declare the emergency should be elevated. If you are a private pilot with 100 hr, but only flew 15hr in the past year, you should never hesitate to get help. From my inquiries, the bulk of our professional pilots have no problem requesting assistance.
Here's an analogy to consider: You live next door to a neurosurgeon, and someone in your house just slipped, fell, and is unconscious. You look out the window and your neighbour is washing his Lexus in the driveway. Would you hesitate to run out and ask him to get his wife to come over and diagnose your friend? (He is an Embraer145 first officer on three-months unpaid leave for not declaring an emergency and not following SOPs during a pilot proficiency check, so you wouldn't want to take his advice about any kind of emergency situation!)
Whatever type of aircraft you are flying, chances are there is another pilot or controller within radio range who has been there and done that, and I have yet to meet one who would not lend a hand.
When in doubt, don't worry about it, and declare! The answers to the five questions at the beginning, then, are respectively: a bit of excitement, no, no, no and no.
by Rob Freeman, Acting Program Manager, Rotorcraft Standard, Certification and Operational Standards, Standards, Civil Aviation, Transport Canada
Since external load longline operations were invented, there have been accidents due to the sling equipment becoming snagged and then dragging down the helicopter. Usually the aircraft ends up on its nose, with high vertical g loading and fatal consequences for the pilot, who (statistically) is likely not wearing an upperbody restraint, or helmet.
During the subsequent investigation, one question is always asked, "why didn't the pilot drop the load?" Friends and associates are left puzzled by the apparent oversight to do the obvious: if the load is snagged, release it! Some of these snagged loads have occurred subsequent to system malfunctions, and some were simply a result of the crew not maintaining sufficient terrain clearance. In the Transportation Safety Board of Canada (TSB) accident report A03P0247, which began as an engine compressor/gas producer problem and ended up as a complete engine failure during the turnaround and approach to land, the TSB noted:
"The location of the external cargo release switch varies on different helicopters and with different operators....In the accident helicopter, the switch position on the cyclic control grip was not what the pilot was accustomed to....Therefore, it is probable that the pilot's action during the emergency did not activate the external cargo hook release mechanism and, rather, that the trailing longline snagged a tree while the helicopter was still airborne. This factor was an additional complication to the survivability aspects of this accident; it could not be speculated whether items such as the pilot's safety harness or seat, or the aircraft's vulnerability to impact forces or post-impact fire would have permitted the pilot to survive the impact."
It is true that the release switch placement may have delayed or prevented the pilot from jettisoning the load. However, this pilot had time to realize a problem was developing with the engine, and had actually turned back toward the take-off pad before snagging the line. There was a reasonable amount of time to locate and activate the release, and yet this was not done. Wouldn't the wellexperienced pilot have depressed the emergency foot release, if the primary emergency release could not be quickly located? Another thought: no one wants to pickle a load unless it is unavoidable. It may be that rather than searching for the switch, the pilot was trying to get back to the pad with the load intact, and delayed the release. When the load became caught, the decision may have been out of his hands, literally.
Artist's impression of catastrophic contact between a light sling load and the tail rotor assembly
In another longline accident (TSB report A00A0076), a Bell 212 was slinging empty drums from a lighthouse. It was the last load of the day, and the weather conditions were favourable-clear, with a strong wind. For some reason, shortly after takeoff, the helicopter descended until water contact was made with the load, and all was lost. The hook assembly was violently displaced 0° to the rear at water contact. The rotor system suffered mast bumping and shearing during the accident sequence. The tail boom and the tail rotor assemblies separated from the aircraft in flight.
I mention this accident because of the very sudden and severe departure from controlled flight. Anyone who has worked around a sling operation can tell you the ground crew will normally watch the arrival and departure. Once the helicopter is established in a climbout, interest wanes, and people return to whatever it was they were doing. In this case, the one witness stated that he turned, noticed a splash, and couldn't see the helicopter anymore. The fact that the helicopter contacted the water in sight of the departure point, after being initially monitored by several people, means that the complete accident-from event initiation to crash-probably occurred in a matter of seconds. The point here is that the reaction time to save the aircraft must have been almost zero. Load/water contact, violent aircraft pitching, mast shearing, and airframe immersion occurred so quickly that only a single splash was seen. Again, why did the experienced pilot not release the load?
During external cargo operations, the load acts like a pendulum, oscillating around the point of attachment- the cargo hook. The pilot, through the judicious use of the flight controls and a healthy measure of concentration and skill, minimizes the oscillations. A good longline pilot makes it look smooth and easy. It most definitely is not either of those things, and is an area of helicopter flying where good training, experience, and "seat-of-the-pants" talent are irreplaceable.
Sadly, all of this can change very suddenly when the load gets snagged on a tree or other ground-level object. The delicate balancing act falls apart. As the line becomes taut, the pendulum is reversed, and the helicopter effectively becomes the "load." All movement now occurs around the fixed ground pivot point (the snag), and the resulting flight path is an arc, until the helicopter strikes the surface in a nose-low position. At the exact moment the snagged line becomes taut, the centre of gravity will be dramatically shifted far outside the limits of what can be countered by the flight controls. Unless the line can be slackened or the load released, recovery is impossible, and the time to impact is only a few seconds away.
If you are lucky enough to be moving forward slowly when the snag occurs, you may have time to recognize the problem and save yourself. A helicopter with a 100-ft longline, travelling forward at a relatively slow 30kt, or approximately 50ft/s horizontally, will strike the ground or water two seconds after snagging the load. At 60kt, you have one second. That's not much time to react, even for the best of pilots. Forward momentum is translated into a circular acceleration vector toward the ground. This phenomenon is dynamic pitch over, with the same causal factors and potential for catastrophe as dynamic rollover.
Think about it. You are flying along at low level with a load, and suddenly have to deal with some malfunction or distraction, i.e. strange engine noises. Your mind is occupied with the problem, what you are going to do, plus where you are going, and the radio calls that need to be made. It is normal pilot behaviour in this situation, perhaps at the subconscious level, to instinctively lower the collective to begin to reduce airspeed and altitude. This may be the last link in the accident chain, as the clearance between the ground and the load is inadvertently zeroed out. There is a sudden and violent rearward tug on the airframe, with banging noises due to fuselage contact with the sling hook or gear. As the nose suddenly and dramatically drops, and you sense an uncommanded, steepening descent, wouldn't your first reaction be to apply aft cyclic, rather than releasing the load? And when the nose drops further, wouldn't the contradiction between your aft control movement and the opposing airframe reaction confuse and delay any other response? With only a second or two between initiating event and surface contact, this may preclude any other reaction until it is too late. Is this "time crunch" during pitch over the root cause for these accidents? You might recall how quickly a rollover accident becomes inevitable once collective is increased for comparison. It is a chilling thought.
If your company only conducts external load operations seasonally, such as on forest fires, it is especially important that your training syllabus include some quality hands-on practice to establish competency. Learning slinging skills without a thorough qualification program is a very large gamble. And all pilots are not created equal. Schedulers and management should take into account individual experience and ability before assigning personnel to these activities. Slinging is a specialized skill that not everyone can do well. In fact, some other countries' aviation authorities require special pilot licensing endorsements to conduct external load operations. In Canada, we leave it to the air operators to establish programs and training for this potentially difficult task.
I encourage all pilots and operators who are involved in external load operations, to have a look at the three TSB reports referenced below for starters (A05Q0119 is also profiled in the Recently Released TSB Reports section, on page29.) Make sure that everyone involved is clear on the dangers and risks of longlining too close to Mother Earth, and delaying the decision to release the load when things start to go wrong. Otherwise, you could be next.
An Aviation Safety Advisory from the Transportation Safety Board of Canada (TSB).
On July10, 2007, a Piper PA31-350 departed from Matheson Island, Man., en route to Poplar River, Man. Shortly after liftoff, the right engine (Lycoming LTIO-540-J2BD) lost power. The pilot secured the engine and turned the flight back to Matheson Island. The aircraft lost altitude in the turns, and the pilot carried out a forced landing in a marsh. The pilot and seven passengers exited the aircraft and were taken to a medical facility. One passenger suffered serious injuries. The pilot and three passengers sustained minor injuries. Three passengers were not injured. The aircraft sustained substantial damage. The TSB investigation (A07C0119) into this occurrence is ongoing. Matheson Island is a registered aerodrome, elevation 725ft, with one gravel-surfaced Runway 03/21, 3 500ft long, oriented 028° and 208° respectively. The observed weather at Berens River, Man., 38NM north of Matheson Island, was as follows: temperature 18°C, winds north-northeast at 4kt. The winds at Matheson Island were estimated as northwest at 10kt, gusting to 18kt, producing a left crosswind component on Runway03. The aircraft had been modified, and the modification increased the maximum approved gross take-off weight of the aircraft from 7000lbs to 7368 lbs. The aircraft's gross weight at takeoff was 6978lbs and the centre of gravity was within approved limits. On departure, the pilot conducted a rolling takeoff on Runway03 with a flap setting of 15° and an engine power set to 2 575 rpm and 42 in. of manifold pressure. The aircraft rotated near the departure end of Runway03 at about 72 kt. Almost immediately after liftoff, the right engine lost power. The pilot raised the landing gear and flaps, shut down the engine, and feathered the propeller. The pilot completed several gradual turns to return to Matheson Island. The aircraft did not climb above about 200ft during the flight and did not accelerate to its best rate-of-climb airspeed of 107kt. The aircraft lost altitude during the turns and the pilot was required to carry out a forced landing. The right engine was recovered and examined, and its turbocharger differential pressure controller was found to be faulty. The fault would have shut down the turbocharger and led to a significant power loss. The aircraft was not equipped with any flight recorders, nor were they required by regulation.
The aircraft's engines were equipped with turbocharger controllers designed to set maximum take-off power automatically when the throttles are fully advanced. The approved aircraft flight manual (AFM), Procedures section, indicates that the take-off procedure is, in part: "a. Throttles-full forward," and, "b. Manifold pressure (43 in. normal-static sea level, std. temp.)-checked." The AFM Limitations section indicates that each engine is rated to produce 350hp at 2 575 rpm and that the maximum allowed manifold pressure below 15000 ft is 49in. The single-engine climb performance chart in the AFM is based on a functioning-engine power setting of 2 575rpm, full throttle, landing gear up and flaps up. The emergency procedure for an engine failure specifies a power setting of "props-forward" and "throttles-forward. "The ambient temperature and elevation would have induced the turbocharger controllers to increase power above the minimum of in. manifold pressure, had full throttle been selected during the takeoff.
The operator was using a quick reference handbook (QRH) that had been compiled by the previous operator, and which was provided to them when the aircraft was purchased. The QRH listed various procedures and limitations, including a take-off power setting of 2 575 rpm and 37in. to 42 in. of manifold pressure. The QRH was not approved by Transport Canada for their operation, and it does not supersede the AFM. The operator's use of the QRH procedures had the effect of reducing manifold pressure and engine power during the occurrence takeoff, increasing the take-off distance and reducing the aircraft's airspeed and altitude, thereby placing the aircraft in closer proximity to obstacles at the time of the engine power loss during the initial climb.
It was not determined how many other operators are using unapproved reference material in their flight operations, or how many operators are aware of the differences between approved and unapproved reference materials.
Although this TSB investigation is still in progress and findings as to causes and contributing factors have yet to be determined by the Board, the operator's use of the unapproved QRH may have been a factor in the occurrence, in that the aircraft was likely at a lower altitude and airspeed at the time of the power loss than it would have been had the correct procedures been followed.
Therefore it is suggested that Transport Canada may wish to take action to ensure that operators are aware of the need to use approved flight operations reference material, and that they ensure that crews are using the correct flight operations references.
This article is a first for our newsletter; it is the brave and poignant story of the survivor of a serious aircraft accident. Lina Ouellet has graciously agreed to share her harrowing experience with Aviation Safety Letter (ASL) readers. This was doubly difficult for her because of the physical and emotional damage that she had to face with great courage over the last two years. We often publish articles about tragic events, but rarely about the consequences. This article is intended to fill this void by conveying the human side of the story. But first, a little background.
A little over a year ago, a resident of St-Ubalde-de-Portneuf, Que., contacted me to ask if she could get a copy of the report on a deadly accident involving a small aircraft that occurred on July16, 2005, near her home. She had a special interest in this accident because her son was the first witness on the scene and the first one to assist the survivor. After checking with the Transportation Safety Board of Canada (TSB), we quickly identified the accident in question (fileA05Q0120), which was not subject to an in-depth Class3 investigation, but rather a Class5 investigation (see page38 to read about the difference between a Class3 and a Class5 investigation).
The aircraft was an amateur-built Zenair Super Zodiac CH601-HDS, which was conducting a visual flight rules (VFR) flight between Lac-aux-Sables, Que., and St-Lambert-de-Lauzon, Que. The pilot, accompanied by his wife and their small dog, reported engine trouble and had to make an emergency landing in a field near Saint-Ubalde. The landing was rough and the aircraft caught fire. The pilot helped his wife evacuate, but he was trapped in the cockpit and died. The passenger was seriously injured, and the aircraft was destroyed by the fire.
Accident aircraft pictured at an air rally prior to the accident
Photo: Pierre Langlois
Nearly twoyears later, the woman from St-Ubalde who was looking for the accident report told me that the survivor had spent nearly two years in rehabilitation, including treatment at the severe burn unit in Québec City and a long-term rehabilitation centre, and that she had finally returned home. It was then that I decided to ask this brave woman if she would be willing to share her story. She agreed, and sent me a very moving story. A translated version is reprinted below:
It was July16, 2005; finally Saturday was here. My husband got up and looked out the window. A wide grin came over his face. The day was going to be nice and hot, which wasn't really surprising, since it was the middle of July. It was the perfect day for a nice flight.
My husband had organized a day of swimming at Lac-aux-Sables. Two couples who were friends of ours joined us in their own aircraft. We left the house around 8:45a.m. When I closed the door behind me that morning, I never imagined that such a tragedy was about to occur.
Once we arrived at our hangar at the St. Lambert airport, we started preparing for departure. As usual, my husband inspected his aircraft. We were ready to leave, and for safety reasons, my husband always puts our little dog, Capitaine Crochet, in his carrier on board the aircraft; but our dog was very hot, so I let him out of his carrier so that he would be more comfortable. I put him on my lap and I buckled him in with me. My husband, our little dog, Capitaine Crochet, and I took off from the St. Lambert airport at about 10:30 a.m. Everything went well during the flight, and I didn't notice anything out of the ordinary.
We arrived at our destination at about 11:30a.m. All three aircraft landed on the runway at Lac-aux-Sables, and everything seemed perfect for a wonderful day.
Indeed, we did have a wonderful day, and it was now time to leave. My husband walked around the aircraft, going through his checklist. I put Capitaine Crochet on my lap and I buckled him in with me again. We took off at about 5:00p.m. The takeoff was very smooth and we were flying at 2 000ft. There wasn't a lot of turbulence and everything was going well. Then the propeller suddenly started to slow down; it was turning very slowly. I couldn't believe what was happening. I told myself that it was going to start turning normally again, but it didn't. There was nothing I could do. It was like being in a nightmare.
First, my husband contacted a friend, who was on board another aircraft, and told him that we had a mechanical problem and that we had to make an emergency landing immediately. Then, my husband said to me, "don't talk to me now. I have to concentrate on making an emergency landing." I looked at the ground and I felt the aircraft moving into position for its approach. I was so scared that I started kissing my grandmother's ring that I had on my finger and I kept repeating, "grandma, grandma please save us." And then...nothing. The stress was so high that I blacked out. When I regained consciousness, the aircraft had crashed and was in flames.
I yelled, "we're on fire! we're on fire!" and tried to undo my seatbelt but I couldn't because it was too hot and it was burning my fingers. I tried again and this time I managed to undo it. My husband opened the door and pushed me out of the aircraft. I fell onto the wing and ended up on the ground. I rolled away from the burning aircraft, afraid that it was going to explode. I yelled to my husband, "hurry, get out! Get out! Please, get out!" But he didn't come out. I was all alone in the middle of a field. I didn't see anything in the distance. There were no houses or people anywhere. My hero couldn't do anything for me now. He was trapped inside the burning aircraft. I knew then that my husband was dead.
I couldn't see the fire, but I could hear it. The aircraft was a few feet away from me, and I had a very strong taste of fuel in my mouth. I heard a sound, a car and finally a voice. About minutes after the crash, Michel Hardy arrived on the scene of the accident. Despite the horrific scene, he didn't hesitate for one second and he came towards me. He stayed behind me, put his hands on either side of my face and he spoke to me in a trembling, but reassuring voice.
He told me to stay calm and that the ambulance and fire trucks were on their way. I asked him if I was seriously burned, and he said, "no." I asked him if I still had my left leg, and he said, "yes." He left me for a few seconds and approached the burning aircraft to try to help my husband. He saw my husband's body in the aircraft, but there were small explosions coming from the aircraft so he couldn't get any closer. He couldn't do anything for my husband and quickly came back to me. He didn't leave me until the ambulance arrived.
Thanks to his composure and courage, my husband did everything he could to save me, and succeeded. It is also thanks to the composure, extraordinary courage and the calm of an Olympian displayed by fire chief Serge Auger and Michel Hardy (who was only 16years old at the time) that I am alive today.
I was conscious during the entire ambulance ride. I also knew that I was about to begin the biggest fight of my life: to survive, because I had chosen to live. I was admitted to the severe burn unit at Enfant-Jésus Hospital. I had suffered burns to 70percent of my body-my face, my arms and my legs. I had also suffered a compound fracture of my left ankle. After I woke up from being in a coma for a few weeks, I remembered everything: my husband's death, the details of the accident and that I was severely burned.
On October18, 2005, after three months in the severe burn unit at Enfant-Jésus Hospital, I was transferred to Centre François-Charron. A few days after I arrived, I started intensive treatment with several therapists. I wore compression garments, a chin strap, a mask, and orthotic devices for over a year and a half. Wearing compression garments helps the skin's healing process. I still wear the chin strap, mask, and orthotic devices even today.
During my rehabilitation, I had to grieve for three deaths: my husband, my mother and my body. The extraordinary support of my family and my many therapists gave me the strength to overcome these challenges. After 18 months of dedication, motivation, determination, physiotherapy, occupational therapy, speech therapy, and 20surgeries, I left Centre François-Charron on January27, 2007, and I finally went home.
It has been over two years since the aircraft crash. Today, I have reclaimed my life and my personality. I live in a condo with my little dog. Yes, Capitaine Crochet was found two days after the crash by a woman in St-Ubalde. Capitaine Crochet managed to escape and was wearing a tag on his neck with his address.
I am now driving my car. I have even taken an aircraft twice to visit my brother and his family in Florida. I still go for treatment twice a week at Centre François-Charron. And I will have to have more surgery. I'm very proud of how far I've come so far. I can now say, "mission accomplished." Believe me, people will start calling me a "firecracker" again soon.
With great joy, on July13, 2007, I was finally able to meet my rescuers Michel Hardy, his father Réginald Hardy and Serge Auger. It was a real privilege for me to share a meal with the entire Hardy family, who are a very special family. At this meal, I also met the fire chief Serge Auger.
I want to give a big thank you from the bottom of my heart to all the people who were involved in any way in helping me through this ordeal. Michel Hardy and his father Réginald Hardy, the ambulance attendants, the fire chief Serge Auger, the firefighters, the police officers, the severe burn unit at Enfant-Jésus Hospital, and the Centre François-Charron. I send my love to my husband Léonard Corbeil and my family. Without you, I wouldn't be here today to tell my story.
Québec City, August2007
A big thank you to Lina Ouellet, and to all the people who helped prepare this special article, especially Dr. Hélène Berlinguet of St-Ubalde, mother of Michel Hardy and partner of Réginald Hardy. Your compassion was the reason this article was written. -Ed.
An Aviation Safety Advisory from the Transportation Safety Board of Canada (TSB).
On June2, 2007, a de Havilland DHC-3T was transporting lumber from Mayo, Y.T. During the takeoff roll, the aircraft entered an extreme nose-up pitch attitude, rotated to the right, and crashed onto the ramp abeam the runway. The aircraft was substantially damaged. The pilot and sole occupant of the aircraft sustained fatal injuries. The investigation into this occurrence (TSB file A07W0099) is ongoing.
The cargo area for the occurrence aircraft was approximately 16ft 5in. long, and the cargo consisted of lumber varying in length from 10ft to 16ft. The aircraft's take-off weight was determined to be below the maximum certified take-off weight (MCTOW) for this aircraft, and the centre of gravity was calculated to be about 2 ½ in. aft of the aft limit. The load was secured using one 1-in. cargo strap that was placed over the top of the load. The load was not restrained in a manner that would prevent longitudinal movement. It was determined that during takeoff, the load shifted aft, which resulted in the aircraft entering an extreme nose-up attitude, and stalling. The pilot was not able to recover the aircraft from the stall.
Following this accident, the TSB Aviation Safety Information System (ASIS) database was searched for accidents and incidents that were a result of load shifts. Four such accidents were identified, all of which resulted in substantial aircraft damage, death, or serious injury. These accidents occurred in the period from 1985 to 2007.
The restraint of cargo is critical toward ensuring that the aircraft remains within its certified balance limitations.
Failure to do so can result in the cargo moving outside of these limits. The act of securing the load against vertical movement did not prevent the load from shifting toward the rear of the aircraft.
A Canadian Aviation Safety Board (CASB) [now the TSB] investigation (A83-O30045) issued a safety recommendation to Transport Canada in 1985 (CASB85-002), where it was recommended that Transport Canada:
- Review its audit system to ensure emphasis on the area of aircraft weight and balance and security of cargo.
Transport Canada responded that articles on aircraft overloading were included at intervals in Transport Canada publications that are distributed nationally. A national campaign against overloading would continue to be part of Transport Canada's master surveillance plan. However, Transport Canada's response did not specifically address the security of cargo issue raised in recommendation CASB 85-002.
Transport Canada's Canadian Aviation Regulation (CAR) 602.86(1) does state in part that "no person shall operate an aircraft with...cargo on board, unless the...cargo [is]
"(b) restrained so as to prevent them from shifting during movement of the aircraft on the surface and during take-off, landing and in-flight turbulence."
The company operations manual stated that all cargo had to be secured to prevent shifting in flight. The aircraft was equipped with multiple tie-down points, and eight cargo straps. The company aircraft ground training exam contained a weight and balance exercise. However, there was no indication of load security training.
While the frequency of this type of event remains relatively low, the result of a load shift as a result of improperly restrained cargo can result in a loss of control, resulting in substantial aircraft damage, serious injury, or death. Transport Canada may wish to inform industry of the significance of load shifting on aircraft performance and the need to effectively secure cargo in order to reduce the risk of in-flight load shift.
CARs Standards 723.105(q) and 724.121(q) require information on securing cargo to be included in the company operations manual (COM). There are several references to cargo in the Standards, and the most notable one is the requirement to have the securing of cargo in the COM. Since part of the operational training is to cover the contents of the COM, the operator is required to train their personnel accordingly. While the Standards do not specifically state any training on how to secure a load, CAR 602.86(1) is clear that a load must be restrained to prevent shifting. Transport Canada does not believe there is a need to change any regulations or standards.
Operators should develop procedures and provide the appropriate training to their personnel to ensure they understand how to properly secure cargo in their aircraft and verify that load shifting will not take place. -Ed.
by Gerard van Es, National Aerospace Laboratory (NLR), Amsterdam, The Netherlands
Many pilots (both commercial and private) tend to underestimate the importance of proper weight and balance of their aircraft. Load sheets are taken for granted, and hasty calculations are made of the aircraft's centre of gravity (CG). Unfortunately, each year there are a number of accidents related to weight and balance issues. Many of these occurrences could have been avoided if more attention was given to the weight and balance.
Aircraft are designed and certified to operate within certain weight and balance limits (see Canadian Aviation Regulations (CARs) Standard 527.27-Centre of Gravity Limits). Exceeding these limits can be dangerous. The regulations provide the stability, controllability, and strength requirements at all allowable CG positions and corresponding weights. The extreme forward and aft CGs must be established for all certified weight limits. The condition that typically determines the forward CG limit is that the aircraft shall be controllable on landing. This means that the aircraft shall be able to be trimmed at the high lift values required for the desired landing speeds (including abuse cases). Other flight control cases that can influence the forward limit of the CG are the capability to make a prompt avoidance pitch-up manoeuvre, the capability to make a prompt nose-down recovery at low speed, and adequate pitch control in abnormal configurations (failure cases). The above-mentioned conditions all apply to free air. On the ground, the forward CG limit is basically determined by the maximum loads on the nose landing gear for an aircraft with a tricycle gear configuration.
Static longitudinal stability is the most important factor in determining the aft CG limit. At the aft CG limit position, the aircraft should demonstrate that a positive natural stability exists, that the aircraft is capable of pitch control at low speeds and high thrust (e.g. during a go-around), and that an adequate control is possible in abnormal configurations. On the ground, the aft CG limit is determined by the minimum loads on the nose landing gear required for good nose wheel steering, the maximum loads on the main landing gears, the tipping tendency of the aircraft, and adequate directional control during the take-off run after an engine failure. These last conditions apply to aircraft with a tricycle gear, and not to those with a taildragger configuration.
What happens if the certified limits as defined in the CG envelope are exceeded? From design, the aircraft flight characteristics will be adversely affected whenever the certified limits are exceeded. For instance, as the CG moves aft, the aircraft will become less stable as the CG approaches the neutral point. If the CG lies aft of the neutral point, the coordination and control motions required to maintain a stable flight condition will exceed the capability of the pilot, and the aircraft will become uncontrollable. On the ground, CG aft of the aft limit can result in a tail strike due to the pitch-up of an aircraft with a tricycle gear configuration (even at low speeds during the take-off roll when power is applied to the engines). The effect of a CG position forward of the forward limit is evidenced by a decrease in elevator control capability. Because of excessive stability, the elevator control required to manoeuvre the aircraft is increased. At some point, elevator control might become insufficient to perform required manoeuvres, such as the flare during landing and a go-around. During takeoff, the CG position can be moved forward until it reaches the point where the aircraft is very stable but cannot be rotated, or can only be rotated with great difficulty because the elevator has reached its maximum deflection. An adverse CG position can also have significant effects on the loads imposed on the aircraft's structural components and could cause structural failure. Exceeding the maximum weights as specified in the aircraft flight manual (AFM) does not necessarily adversely affect the flight characteristics. For instance, exceeding the maximum landing weight could result in a landing gear collapse. However, the landing gear structure is designed with a standard safety margin assuming a higher load than obtained during a normal landing at maximum landing weight. With this, it could be possible to land the aircraft somewhat beyond the maximum landing weight. Overweight landings are often made during emergency or precautionary landings. Exceeding the maximum takeoff weight (MTOW) will affect the flight performance characteristics. The take-off ground-roll distance increases and the climb performance decreases. As long as the aircraft is not significantly overweight, it should be able to take off safely. However, the margins reduce rapidly when an engine failure occurs during an overweight takeoff, if the runway is short for the aircraft, or if there are high obstacles along the take-off flight path that the aircraft has to clear.
Aircraft that have wing-mounted propellers can be faced with a unique problem when flying with a CG close to the aft limit. Control can be lost during the approach after selecting landing flaps followed by the initiation of power increase and/or a go-around. Lowering the flap will move the neutral point forward and change the pitching moment (this effect is not limited to propeller aircraft). The pilot feels this as a tendency for the aircraft to pitch-up, and needs to push forward on the control column to hold a steady flight path by lowering the elevator. The pilot will re-trim the aircraft by winding the trim wheel forward, which moves the trim tab to keep the elevator in the new position without the pilot having to maintain a push force on the control column. One feature of aircraft with wing-mounted propellers is that when the engines accelerate from idle power to full power, the neutral point moves forward (up to 10percent of the mean aerodynamic chord!). When the actual CG position is close to or slightly aft of the certified aft limit due to incorrect loading, the aircraft may be just stable during takeoff and cruise. However, this situation can change during landing, in which case the aircraft may become unstable after lowering the flaps to landing position, and may show a very strong pitch-up tendency. The normal reaction to increase power to recover from the pitch-up or to make a go-around will make things even worse as the neutral point moves forward significantly with the increase in power on aircraft with wing-mounted propellers.
More information on weight and balance issues can be found in a safety study conducted by the author, "Analysis of aircraft weight and balance related safety occurrences," (Report No. NLR TP-2007-153).-Ed.
The recipient of the 2007DCAM Flight Instructor Safety Award is John Robertson, Chief Flight Instructor and Professor of Human Factors and Safety Systems at the School of Aviation and Flight Technology, Seneca College, Toronto, Ont. Jane and Rikki Abramson presented the award on November5, 2007, at the Air Transport Association of Canada's (ATAC) Annual General Meeting and Convention held in Halifax, N.S.
John had an extensive career in the Canadian military, where he trained on the Sea King helicopter and the Tutor Jet. Among many of his distinguished accomplishments in the military was being the chief flight instructor (CFI) at the Moose Jaw, Sask., military flight training base. "His passion for flight, vast amount of knowledge and enthusiasm for teaching has made him a role model," quote his students. He is also a designated Transport Canada pilot examiner.
The annual DCAM Award promotes flight safety by recognizing exceptional flight instructors in Canada, and has brought much recognition and awareness to the flight instructor community. Recognition of excellence within this segment of our industry upholds a safety consciousness that hopefully will be passed on for many years to come.
The deadline for nominations for the 2008award is September14, 2008. For details, please visit http://www.dcamaward.com/.
From left to right: Rikki Abramson, John Robertson, Jane Abramson, and Mike Doiron, Acting Chairman of ATAC