Thierry Dubois is a freelance writer specializing in helicopters, business aviation and aerospace technology. He earned a degree in fluid dynamics from an engineering school in Toulouse, France in the mid-1990s. At an unexpected crossroads, he found his first job in journalism. In 1997, he started working for French aerospace weekly Air &amp; Cosmos in Paris. This lasted until 2000, when he moved south to Lyons. He then became a freelancer, working for various aerospace publications and has been part of the AIN team since late 2000. In addition to writing about business aviation, Thierry shares responsibility for the rotorcraft section. He also is a regular on-site writer for AIN’s daily editions at international airshows such as the Paris, Farnborough, Dubai and Singapore shows, as well as at EBACE in Geneva.
In 2007, he won the Honeywell award for “Best systems or technology submission” at the Aerospace journalist of the year awards. In 2013, he won an Aerospace Media Award for the "Best Safety, Training &amp; Simulation Submission."
In other activities, Thierry moderates international conferences on aviation technology topics. Thierry is married and has three children, who seem to begin enjoying the mountains–as their parents do.

Writer

Thierry Dubois

A controversy is flaring at the French fireguard about the use of converted Bombardier Dash 8Q-400 turboprops as heavy waterbombers. Pilots deem the aircraft unsuited to their needs and insist that using it has negative implications for safety. The Ministry of the Interior, which ordered two of the aircraft in 2004, has just reached an agreement with the pilots.
During the summer, the aircraft will be evaluated in actual firefighting operations. At the end of the so-called fire season, and depending on the result of the evaluation, the ministry will decide whether to formally add the two Q400s to the French fleet of waterbombers. One Dash 8, as the pilots call it, was handed over last year but the delivery of the second had been put on hold because of the pilots’ concerns. AIN recently visited the Marignane base of Sécurité Civile, France’s civil defense and emergency preparedness organization, to discuss the future of the Q400s.
The controversy hinges on the load-factor limitations of the converted Q400s. In May 2004, the two Q400 multi-role waterbomber conversions ordered from British Columbia, Canada-based Cascade Aerospace included a specification on the load factor. “The specification called for 3.25 g,” recalled base commander Michel Razaire. But Transport Canada (TC) certified the Dash 8 at only 2.1 g at maximum payload and 3 g when empty. “These include margins to the structural limits, which are 2.4 g at full payload and 3.5 g empty,” Razaire added. The structural limit is defined as the point at which permanent deformation begins. The ultimate load is 1.5 times the structural limit; the airframe is supposed to withstand the ultimate load and fail just beyond.
Razaire admitted that the final figures were disappointing. He maintains that Cascade never warned the French fireguard that the conversion might not meet the agency’s requirement. However, a Cascade Aerospace spokeswoman told AIN, “Our contract called for a multi-role aircraft–certified to Transport Canada certification requirements for firefighting, cargo carrying and passenger carrying. Cascade Aerospace met the conditions of the contract by providing the Cascade Q400-MR.” It is fully certified–in all three roles–by Transport Canada.
According to Cascade, “The 3.25-g issue stems from confusion about maneuvering versus structural limitations.” In fact, the Cascade Q400-MR can exceed a 3.25-g load factor in some conditions because of its powerful Pratt &amp; Whitney Canada PW150A engines, the company claimed. Yann Dyèvre, subdirector of operational services at the Sécurité Civile, acknowledged some ambiguity. “Our specifications stated ‘3.25 g (Canadian certification),’” he told AIN.
Razaire supported Transport Canada’s conservative decision and the aircraft’s performance. “TC kept a safety margin in case a wind gust shakes the airframe further when the aircraft is already at its certified limit load factor,” he said. He recalled that both the U.S. and Canada have lost a number of waterbombers to in-flight breakups.
Most important, he emphasized that the relatively low 130-knot water-dropping speed is incompatible with higher load factors. When maneuvering, stall speed is multiplied by the square root of the number of gs. The Dash 8’s water-dropping speed is close to 130 knots, or 1.4 times the aircraft’s stall speed. This is just compatible with a load factor of two–the square root of two is approximately 1.4.
Cascade delivered the first converted aircraft early last summer in time for the fire season. It officially entered service on August 5. But in February of this year the Ministry of the Interior decided to “take time for further reflection” and therefore suspended delivery of the second aircraft. It was delivered late in March.
Pilots Voice Concerns The decision to delay delivery of the second aircraft apparently stemmed from pilot unions’ concerns about safety. In a February letter to Nicolas Sarkozy, France’s minister of the interior, unions for the Marignane-based pilots voiced fears about the Dash 8. “The flight envelope of the delivered aircraft is significantly degraded, compared to that of the production aircraft we were introduced to in 2004,” they wrote. They asked the minister to void the contract with Cascade and launch another call for tender.
They met Sarkozy on March 7 and announced on March 14 that the Sécurité Civile will assess the two aircraft during the entire fire season this year. “A thorough evaluation protocol will determine the best use of the aircraft in early fire treatment,” the Ministry of the Interior stated. In October, the ministry will decide whether the two Dash 8s are definitively part of the fleet. If they are not, the French State will either try to find another application for them or try to sell them on the used market.
Pilots had been expressing concern about the use of a converted airliner since 2004. The fireguard bought the Bombardier-built aircraft from SAS Scandinavian Airlines, which had been using them as regional turboprops. “Lessons have not been learned from the acquisition of the Fokker F.27s [which the Dash 8s are replacing], 20 years ago,” the unions had written earlier.
The Ministry of the Interior recently pointed out that “during the summer of 2005, the aircraft proved it was efficient.” In late August last year, French aerospace weekly Air &amp; Cosmos reported that the aircraft was responsible for more than 62 retardant deliveries on some 20 forest fires. The aircraft carried a load of approximately 2,400 U.S. gallons of fire retardant, enough to treat an area 650 feet long by 30 feet wide.
The new aircraft can help the Sécurité Civile’s Bombardier CL-415 turboprop amphibians–Canadairs, as they are called in France–on a major fire. But they will be used mainly in “armed airborne watch” missions. A commonly used strategy at the French fireguard, these missions call for airplanes fully loaded with fire retardant to loiter above forest areas that weather forecast services have determined to be “at risk” on that day. Their job is to detect forest fire starts and drop fire retardant to prevent a fire from spreading.
Pilot unions insist that the aircraft will be either useless or dangerous for such observation missions. “In many instances, because of the lower load-factor limitations, crews will be unable to do what our Trackers [the common name for the Conair Turbo Firecats] do,” a pilot told AIN.
On other occasions, the aircraft is supposed to support firefighters on the ground, perhaps by dropping retardant along a road. “If the crew cannot deliver what the firemen are used to relying on, the people on the ground will be seriously disappointed,” the pilot said. But the worst case may happen when the pilots are tempted to see what they can do and turn a blind eye to the risk of overstressing the airplane.
When the first Dash 8 was delivered last year, Transport Canada had granted it provisional certification. A pilot recalled that the certification was “2.4 gs at full load and 3.5 when empty,” figures that were already below the French state’s specification. But the final certification, which was issued at the end of the fire season, resulted in significant markdowns, to 2.1 g and 3 g, respectively. Pilots regard those as all the more insufficient since they say the Sécurité Civile’s CL-415 turboprops can withstand load factors of up to 3.25 g at full payload.
The French procurement agency has now asked Transport Canada for more details about the Sécurité Civile’s CL-415s’ and Conair Turbo Firecats’ limitations. Their limit load factor has so far been defined without specifying whether it is a structural limit or an operational allowance. “A fully loaded CL-415 dropping water on a fire cannot go beyond 2.5 g, simply because of its stall speed,” Dyèvre asserted. Razaire has apparently second-guessed himself a lot. “On the Dash 8, we were asking too much,” he estimated.
The Ministry of the Interior evaluated several firefighting aircraft before selecting the Dash 8. It also considered plans for converting Lockheed C-130 and Convair 580 turboprops. The Russian-made Beriev Be-200 twinjet appeared to be a serious contender at one point because it was the only one designed for scooping and its capacity–12 metric tons of water–is higher than the Dash 8’s 10-metric-ton capacity. However, “Beriev would not have been able to deliver any aircraft by the summer of 2005,” Razaire said. In addition, the ministry wanted a multi-role aircraft that would also be able to carry passengers.
The quick-change Dash 8 is in fact not only a waterbomber. It can be used also as a passenger or cargo transport. It takes five hours to adapt the waterbomber kit, the most visible part of which is the water tank and delivery system under the fuselage. The Dash 8 can cruise at 240 knots in waterbomber configuration. It is equipped with a head-up display and, without the water belly, can fly into known icing conditions. Like every airplane in the Sécurité Civile’s fleet, it is certified for IFR operations.
The Dash 8 also features a flow-rate control computer. During retardant or water delivery, the flow can be kept constant automatically. The crew first selects the amount of water to be delivered per square foot. The software program takes into account the speed and determines how long and how wide the doors should be open. The crew can also choose between full load, half load or quarter load delivery. The airplane’s water-delivery height is close to 100 feet. Retardant dropping calls for a 150-foot height.
Safety-improvement Plans But all these features are not enough to convince the pilots. Indeed, a series of fatal accidents last summer is rooting the malaise more deeply. During a short period of time, four crewmembers died in three crashes that destroyed two Trackers and one Canadair. These accidents brought the number of fatalities to more than 30 in 28 years of operation.
The most disturbing accident was the in-flight breakup of a Canadair in Corsica. As the aircraft was about to drop water on a fire the aft fuselage–complete with vertical and horizontal stabilizers–detached. The airplane had not hit any obstacle. The crew of two died in the resulting crash. The entire Canadair fleet was grounded temporarily for inspection.
No cause has been found yet, although the investigation has ruled out pilot error, the district attorney said in February. 
He suggested “a column of hot air” might have stressed the aircraft beyond its structural tolerance limits. However, it can be argued that these aircraft routinely fly into such severe turbulence when above fires. The final report on the accident is expected to be released by next month.
“What happened last summer is clearly unacceptable,” Razaire stated. In response, a safety action plan is being implemented. The first action is related to crew resource management. “The co-pilot of a Canadair will have his own missions; we felt that the current breakdown of the roles in the cockpit might blunt his decision-making skill,” Razaire explained.
Diversifying recruitment is also envisioned. Most pilots hired at the Sécurité Civile are former fighter pilots from the French air force or navy. Razaire and his team now want to “mix cultures,” as he put it.
Another measure aimed at improving safety is the use of quick-access recorders to analyze each flight. “We want to change those behaviors and procedures that need to be corrected,” Razaire said. The Sécurité Civile is now hiring analysts.
The current level of training–60 flight hours per pilot–between the two fire seasons, from October to May, will remain the same.
Other measures are still under discussion. Among them is the pilot seniority system. For example, a pilot usually starts as a Canadair copilot. He is then appointed pilot of a single-pilot Tracker. Finally, he returns to a Canadair cockpit as a captain. “Wouldn’t it be more consistent to move directly from the right to the left seat in a Canadair cockpit?” Razaire asked rhetorically. Perhaps, but the pilots currently flying Trackers are waiting for their turn on Canadairs.
The Canadair Workhorse The Bombardier CL-415 amphibian is the Sécurité Civile’s workhorse. It can scoop up a water payload of nearly 14,000 pounds. Bombardier delivered a new one in January, bringing the fleet to 11 again. However, it is still undergoing an internal technical standardization process and is therefore not yet in service.
The Canadair’s water-drop speed is 110 to 115 knots. The water-drop maneuver consists of a turn that is tangential to the fire’s border. “The pilot arrests the turn and keeps the wings level while the water is being dropped,” Razaire told AIN. A Canadair pilot added that the way water is dropped depends on the type of fire. “On a big blaze, we open both water bays simultaneously,” he said. For a smaller one, they are opened with a one-second interval in between.
In the water tank, chemical foam is mixed with the water to enhance its extinguishing power. The ratio of foam to water depends on the kind of vegetation that is burning. “In Corsica, the vegetation is very dense so we put little foam into the water we have scooped, otherwise the resulting mix does not penetrate deeply enough into the forest,” the pilot said.
A CL-415 can nominally perform five water deliveries per hour–more if a suitable water surface is close to the fire. At the end of a busy day, a Canadair can land after having performed 80 cycles in 10 flight hours. The delivery rate falls to two water drops per hour if the airplane has to land on a runway to refill its water tanks, Razaire explained.
The Sécurité Civile did encounter some teething problems with the CL-415 as well–corrosion due to salt water, since resolved by rinsing the airframe, water bays and engines daily with soft water. Maintenance, repair and overhaul service provider TAT Industries maintains the three Beech King Airs (used for liaison missions), the 10 Conair Firecats and the 11 CL-415 amphibians. Standard Aero looks after the entire fleet’s engines.
The Firecat fleet consists of nine Turbo-Firecats and one piston-engine Firecat. All the airframes are more than 30 years old. The Firecats used to be Grumman Trackers, maritime patrol and sub-hunting aircraft in the U.S. Navy. They were then refurbished twice. The first conversion turned them into firefighters and the second replaced their Wright Cyclone nine-cylinder radial piston engines with Pratt &amp; Whitney Canada PT6A-67AF turboprops. One Firecat in the Sécurité Civile’s fleet has kept its piston engines, but that aircraft will be retired this fall.
While the CL-415s can scoop nearly 1,670 gallons of water on the run, the Trackers, as they are usually called, cannot scoop. But they carry nearly 850 gallons of fire retardant. They fly in two-airplane loaded airborne watch patrols of 2.5 hours.
A plan is under way to prolong the life of the aging fleet of Trackers to 2020. Razaire has already started to think of their replacement. He told AIN he wishes an equivalent were available now to replace those aircraft lost in recent years. But he cannot find any, he said.
Some 150 people work at the Marignane base, and 85 of them are pilots. As a whole, they log about 10,000 flight hours between June and September. The base’s annual budget is $54 million, Razaire said. With fleet-renewal costs, the total budget is $72 million.
Some 37,000 acres of forest burn every year in France. In 2003, a peak year for forest fires because of the hot, dry summer, four times this area burned. However, a significant portion of the fires are criminal.

Pilots stall delivery of 2nd Q400 to French fireguard

A controversy is flaring at the French fireguard about the use of converted Bombardier Dash 8Q-400 turboprops as heavy waterbombers.

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