A Pratt & Whitney JT9D-7R4D left turbofan engine burst into flames on a taxiing Dynamic International Airways Boeing 767-200ER, carrying 101 passengers and flight crew, just prior to its departure at Fort Lauderdale-Hollywood International Airport (in Dania Beach, Florida USA) en route to Caracas, Venezuela.
Photo Credit: Flicker.com, Dynamic Aviation Group Boeing-767-300ER, Registration Number N251MY
The 29-year-old Boeing 767-200ER airliner, Registration Number N251MY, operating as flight 2D-405 on Thursday, October 29, 2015, was taxiing on the ground before departure at about 12:34pm ET, holding short of Fort Lauderdale Airport’s runway 28R after contacting the local air traffic control tower.
Suddenly, the flight crew of another aircraft, taxiing behind Dynamic International Airways flight 2D-405, advised the flight deck of the Boeing 767-200ER airliner that there was a massive Jet A-1 fuel leak from the left Pratt & Whitney turbofan engine (JT9D-7R4D).
Pratt & Whitney developed the first high bypass ratio turbofan engine (JT9D-7R4D) to power a wide-body airliner, originally designed for application to the first Jumbo Boeing 747-100 airliner.
Immediately, the flight deck of the Boeing 767-200ER airliner acknowledged the fuel leak and then requested to return to the ramp.
That was when the other advising flight deck airliner, taxiing behind flight 2D-405, alerted the Boeing 767-200ER flight deck that the new condition of their aircraft was their left turbofan engine was now on fire!
According to Reuters, at 12:34pm ET the Boeing 767-200ER airliner was evacuated via slides in about 3 minutes.
Luis Campana, a 71-year-old rancher, along with his wife and sister, were three of the 101 passengers and crew on-board Dynamic International Airways flight 2D-405 traveling to Venezuela’s Guarico state.
“It was a real scare,” Campana told Reuters at Fort Lauderdale-Hollywood International Airport. He said, “he had been sitting near the front of the plane, as the pilot put the thrust on to taxi up the runway.”
“The engine exploded. As we were getting out of the plane down the chute, the smoke was beginning to enter and the engine was in flames,” he said.
Twenty-one people were injured, one seriously, most of whom were treated at a hospital and released, said Broward Sheriff Fire Rescue spokesman Mike Jachles.
Don Dodson, the director of operations for Dynamic Airways, said airline officials had set up a crisis center, flown in additional airline representatives to help passengers and arranged for a relief flight to take passengers to their final destinations.
Emergency services responded in two minutes at 12:36pm ET, according to Mike Jachles of the Boward County Fire Rescue, upon which firefighters extinguished the fire using foam seven minutes later at 12:41pm ET.
The National Transportation Safety Board has initiated its investigation of the Boeing 767-200ER fire that injured several passengers on the tarmac at the South Florida airport Thursday, according to Greg Meyer of the Boward County Aviation Department.
The plane had no previous incidents or issues, the Federal Aviation Administration said.
The Boeing 767/269 — manufactured in 1986 and owned by Utah-based airplane leasing company KMW Leasing in Salt Lake City — lost 45 to 50 gallons of fuel, damaging the asphalt. Taxiway repairs should be complete later Friday or Saturday, Fort Lauderdale/Hollywood International Airport Director Kent George said (via Fox News).
“More than 100 passengers had to evacuate using emergency slides. Some ran from the plane into the terminal as fire crews rushed to put the fire out,” Fox News reported.
Kent George, Director of the Broward County Aviation Department, said (via Fox News), “the flames never entered the cockpit.”
Dynamic International Airways, according to the limited liability company founded in 2008, is a certified Part 121 Carrier, operating fleet of seven Boeing 767-200ER aircraft that typically carries up to 250 people. The air carrier is based in Greensboro, North Carolina that connects Fort Lauderdale, New York, Venezuela and Guyana.
In past Dynamic International Airways operated mostly for other carriers and tour operators under their wet lease agreements.
In 2014 the airline started its own passenger service on multiple international markets including China, Saipan, Guam, Hong Kong, Guyana and Brasil.
Only recently, Dynamic International Airways announced it has launched its low-cost service between Fort Lauderdale, Florida and Caracas, Venezuela.
“For Venezuelans hoping to travel abroad, the options have been severely reduced to little-known carriers such as Dynamic or domestic carriers, which due to the country’s economic crisis, have struggled to import replacement parts,” according to Fox News.
We can all emotionally recall, we had seen a similar massive fire with thick black smoke bellowing high in the sky, resulting from extremely hot Jet A-1 engine fuel inside the World Trade Center fire fourteen years ago on 9-11-2001.
Therein, that tall building’s constructed steel melted, when it reached a temperature of 800 degree Fahrenheit, as a result of forced mixing with a highly flammable Jet A-1 engine fuel, which burns at an extremely hot temperature approaching 2000 degrees Kelvin.
When Jet A-1 fuel burns uncontrollably, it induces a thick bellowing cloud of black smoke.
Still, experts present another scenario of truths associated with the Boeing 767-200ER’s Pratt & Whitney JT9D-7R4D engine safety breach of an undetected fuel leak prior to takeoff.
The accident could have been catastrophic had the jet taken off with a fuel leak, Greg Feith, a former crash investigator for the National Transportation Safety Board, told Reuters.
“Once the aircraft is airborne, it becomes a flying blowtorch,” Feith said. “The fire intensifies and you don’t know what system or structure it’s going to burn through.”
Fire could damage a wing and fuselage, or cripple hydraulic and electronic control systems, Feith said, potentially making an emergency landing impossible. It could also ignite fuel tanks in the wings, especially if fuel vapor were present, he said.
How do aircraft engines achieve catastrophic mechanical failure and how can this be mitigated?
Air enters the Pratt & Whitney JT9D-7R4D turbofan engine through the fan section (indicated in the photo below) at a mass flow rate of about a ton of air per second.
Five parts of this massive volume of air passes bypasses over the engine core into an exit nozzle past the turbine section, producing a substantially large amount of exit thrust. Whereas, one part of the inlet fan volume of air passes into the engine core begin at the compressor section.
From here air then continues to flow into the combustor (where it is mixed with fuel for combustion).
Subsequently, those combusted, hot gases pass into the turbine section (which not only produces additional exit thrust force of the engine, but also the turbine section serves to turn the engine core shaft, which turns the compressor blades inside the compression section and also the fans blades inside the fan section, and thus, start all over again the dynamic loop of how an aircraft engine properly operates).
The rotor blades in the turbine get very hot at about 1,800 degrees Kelvin or even more, so it is necessary to cool the turbine blades based on limiting thermal restrictions on material science. The tangential on-board injector’s job is to channel cool air from the compressor section into passages between the turbine blades in the turbine section.
Here is a cut-away of an actual Pratt and Whitney JT9D-7R4D turbofan engine in a museum, marked it up to help us see where the main engine components of the fan, compressor (including the air-fuel combustion chamber), and turbine sections are (including the identified portion that landing on Church and Murray Street, below the World Trade Center fire on 9-11):
The operating range of aircraft turbofan engine compression systems is limited by two classes of aerodynamic instabilities (Fig. 1) known as rotating stall and surge .
Rotating stall is a multidimensional instability in which regions of low or reversed mass flow (i.e., stall cells) propagate around the compressor annulus due to incidence variations on adjacent airfoils [2–5].
Surge is primarily a one- dimensional instability of the entire pumping system (compressor, ducts, combustion chamber, and turbine). It is characterized by axial pulsations in annulus-averaged mass flow, including periods of flow reversal through the machine.
In high-speed compressor hydrodynamics across compressible flow regimes , rotating stall is generally encountered first, which then (loosely) “triggers” surge (often after a few rotor revolutions ).
This work  proposes schemes to passively control compressible rotating stall of high-speed compressors.
Nonetheless, with either instability, the compression system experiences a substantial loss in performance and operability, which sometimes result in catastrophic mechanical failure.
An experience-based approach for avoiding such performance loss is to operate the compressor at a safe range from the point of instability onset (i.e., imposing a stall margin). The stall margin ensures that the engine can endure momentary off-design operation. The margin also reduces the available pressure rise and efficiency of the machine (see Fig. 2).
It is proposed here that incorporating tailored structures and aeromechanical feedback controllers, locally-sensed by unstable compressible perturbations in annulus pressure, and actuated by non-uniformities in the high- speed flow distribution around the annulus, can be shown to inhibit the inception of a certain class of modal (long wave) stall of high-speed compressor devices. As a result, the stable operating range will be effectively extended allowing higher compressible performance and operability.
The fundamental proposition here  is high-speed stall onset just does not happen—it is triggered by an interdependent compressibility chain of critical Reynolds (boundary layer) and Mach (kinetic-thermal energy transfer) events. The commencement of these interdependent Reynolds and Mach events can be passively controlled, once their proportional sensitivity are monitored, sensed, and mechanically mitigated adequately in balance of performance, operability, weight, and reliability integrated with more conventional schedule-type control to justify the risk of such passive approaches offered herein.
In theory, fundamentals of a number of sensor-actuator schemes for rotating stall control were originally proposed early-on in Hendricks and Gysling . In practice, a passive stall control program  could potentially be integrated with conventional control schedules of adequate change of fuel valve position, bleed valves, and re-staggered stator programs developed appropriately for profitable usage on compression systems operating in a highly-sensed compressible flow environment.
Fundamental References for Additional Readings in the Field of Aircraft Engine Propulsion Stability
Emmons, H. W., Pearson, C. E., and Grant, H. P., 1955, ‘‘Compressor Surge and Stall Propagation,’’ Trans. ASME, 77, pp. 455–469.
Greitzer, E. M., 1976, ‘‘Surge and Rotating Stall in Axial Flow Compressors, Part I & II,’’ ASME J. Eng. Power, 99, pp. 190–217.
Greitzer, E. M., 1980, ‘‘Review: Axial Compressor Stall Phenomenon,’’ ASME J. Fluids Eng., 102, pp. 134–151.
Greitzer, E. M., 1981, ‘‘The Stability of Pumping Systems, The 1980 Freeman Scholar Lecture,’’ ASME J. Fluids Eng., 103, pp. 193–242.
Day, I. J., 1993, ‘‘Stall Inception in Axial Flow Compressors,’’ ASME J. Turbomach., 115, pp. 1–9.
Gysling, D. L. et al., 1991, ‘‘Dynamic Control of Centrifugal Compressor Surge Using Tailored Structures,’’ ASME J. Turbomach., 113, pp. 710–722.
Gysling, D. L., and Greitzer, E. M., 1995, ‘‘Dynamic Control of Rotating Stall in Axial Flow Compressors Using Aeromechanical Feedback,’’ ASME J. Turbomach., 117, pp. 307–319.
Moore, F. K., 1984, ‘‘A Theory of Rotating Stall of Multistage Compressors—Parts I – II – III,’’ ASME J. Eng. Gas Turbines Power, 106, pp. 313–336.
Moore, F. K., and Greitzer, E. M., 1986, ‘‘A Theory of Post Stall Transients in Axial Compression Systems: Part I—Development of Equations,’’ ASME J. Eng. Gas Turbines Power, 108, pp. 68–76.
Greitzer, E. M., and Moore, F. K., 1986, ‘‘A Theory of Post-Stall Transients in Axial Compression Systems: Part II—Application,’’ ASME J. Eng. Gas Tur- bines Power, 108, pp. 231–239.
Haynes, J. M., Hendricks, G. J., and Epstein, A. H., 1994, ‘‘Active Stabilization of Rotating Stall in a Three-Stage Axial Compressor,’’ ASME J. Turbomach., 116, pp. 226–239.
Longley, J. P., 1994, ‘‘A Review of Non-Steady Flow Models for Compressor Stability,’’ ASME J. Turbomach., 116, pp. 202–215.
McGee, O. G., and Coleman, K. L., 2013, “Aeromechanical Control of High-Speed Axial Compressor Stall and Engine Performance—Part I: Control- Theoretic Models,” ASME J. Fluids Eng., 135, March 2013. Coleman, K.L., and McGee, O.G., 2013, “Aeromechanical Control of High-Speed Axial Compressor Stall and Engine Performance—Part II: Assessments of Methodologies,” ASME J. Fluids Eng., 135, May 2013.
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