Rogue5
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http://www.popularmechanics.com/science/aviation/2156137.html
'We don't have any engines'
Two joyriding pilots took a jet to its 41,000-ft. ceiling--and paid for the stunt with their lives. PM investigates the crash of Flight 3701.
BY JIM GORMAN
Published in the January, 2006 issue.
For three and a half minutes on the night of Oct. 14, 2004, Capt. Jesse Rhodes and First Officer Peter Cesarz were on top of the world. The two Pinnacle Airlines pilots had pushed their twin-engine, 50-seat regional jet to its maximum altitude and were now proud members of the "410 club," an unofficial society of Pinnacle airmen who've attained 41,000 ft. in a Bombardier CRJ200.
Rhodes went to the galley to grab cold Pepsis to celebrate. He was barely settled back in the cockpit when the plane's radio crackled. "Are you a RJ [regional jet] 200?" inquired an air traffic controller in Olathe, Kan. "I've never seen you guys up at forty-one there."
"Yeah ... we don't have any passengers on board so we decided to have a little fun and come on up here," Rhodes replied.
The fun was short-lived. Moments later, both engines flamed out.
The fate of Flight 3701 is the subject of an intensive investigation by the National Transportation Safety Board (NTSB), which is expected to issue a final report on the accident in the next few months. Until then, neither Pinnacle Airlines, which operates connecting flights for Northwest Airlines, nor Bombardier and General Electric--the airplane and engine manufacturers--can comment on the cause of the accident. However, the pilots' taped cockpit conversations and preliminary hearings last June suggest a scenario involving poor judgment, insufficient training and the complications that can occur when a plane is pushed beyond its capabilities.
TO THE LIMIT
Rhodes, 31, and Cesarz, 23, were on what pilots call a deadhead, transferring an empty plane overnight from Little Rock, Ark., to Minneapolis so it could be ready for a morning flight. The Canadian-built CRJ200 is Pinnacle's workhorse, making short and midrange hops mostly in the Midwest. From wheels-up, it was clear that Rhodes and Cesarz intended to see what the CRJ200 could do.
Four seconds after takeoff at 9:21 pm, the two pilots did a "pitch up" maneuver that pinned them in their seats with 1.8 g's of force and momentarily triggered an alert from the airplane's stall warning system.
Minutes later, Rhodes and Cesarz again yanked back on the control column, rocketing the plane upward and generating over 2.3 g's of force before they eased off the flight controls. After briefly leveling off at 37,000 ft., the crew set the autopilot to climb at 500 ft. per minute--more than twice the fastest recommended rate--to the airplane's maximum altitude of 41,000 ft.
As the plane rose, it succumbed to the physics of high-altitude flight: Thin atmosphere offers less lift and robs the engine of air. Stuck in an aggressive climbing mode, Flight 3701's speed began to drop. To maintain the rate of climb, the autopilot angled the nose of the aircraft up, slowing it further. By the time the aircraft reached 41,000 ft. and leveled off, it was flying slowly, at 150 knots indicated airspeed, and was perilously close to losing aerodynamic lift--or stalling.
"This thing ain't gonna [expletive] hold altitude," Cesarz said.
"It can't man," Rhodes replied. "We [cruised/greased] up here but it won't stay."
The combination of high altitude and low speed once again triggered the Bombardier's stall warning system. First, "stick shakers" rattled the control columns and disengaged the autopilot to alert the crew of an imminent stall. When the crew didn't lower the plane's nose to gain speed, "stick pushers" forced the control columns forward. The flight data recorder shows that Rhodes and Cesarz overrode the stick pushers three times and forced the plane's nose back up. At 9:55 pm, as they pulled up for the last time, both engines flamed out.
"We don't have any engines," one of the pilots said.
FAILED EFFORTS
While the altimeter spun downward, the crew hurriedly reviewed their options for restarting the engines. At that altitude, there were six suitable airports within reach for a forced landing. Despite the serious nature of their predicament, the pilots did not notify air traffic control (ATC) of their situation or request emergency landing clearance.
First, they tried a "windmill restart" by diving to increase airspeed. The maneuver is intended to force air into the engine housing, spinning the rotors and creating enough compression for ignition. The procedure requires at least 300 knots of airspeed. But at 20,000 ft. and only 236 knots, the crew pulled up, and decided instead to try a second option: Drop to 13,000 ft. and attempt to relight the engines using the plane's auxiliary power unit (APU), which generates pneumatic pressure to spin the engine's core.
Rhodes and Cesarz tried at least four times to jumpstart the engines using the APU. On each attempt the engine cores recorded no rotation.
At 10:03 pm, the crew radioed ATC that they had a single engine failure. Five minutes later, at an altitude of 10,000 ft., and descending at 1500 ft. per minute, Rhodes and Cesarz were running out of options for restarting the engines. Finally, 12 minutes after the twin flameout, they revealed to ATC that they had a double engine failure. The plane's landing choices were now limited to two airports.
With the runway lights of Jefferson City airport in sight, but altitude slipping away, Rhodes and Cesarz realized they were in big trouble.
"Dude, we're not going to make this," Rhodes said. "We're gonna hit houses, dude."
They crashed 2-1/2 miles shy of the runway--behind a row of houses. On impact, the plane split apart, flipped over and caught fire. Rhodes and Cesarz were killed. Miraculously, no one on the ground was injured.
THE INVESTIGATION
An area of contention during the NTSB hearings about Flight 3701 has been whether a condition called "core lock" contributed to the fatal crash. Under normal conditions, the rotating parts inside a General Electric CF34-3B1 turbofan engine slip by each other in a finely tuned choreography.
However, when an engine is shut down suddenly at high torque, high altitude, and it isn't restarted immediately, metal parts inside the engine begin to cool and contract at different rates. In rare cases, metal can contact metal and prevent the core from rotating freely--core lock.
The Air Line Pilots Association suggests that core lock, rather than pilot error, might have been the primary cause of the accident. But, a review of the flight data recorder makes clear that the pilots made a series of poor, and potentially fatal, decisions irrespective of whether the engines experienced core lock.
The Bombardier has a 41,000-ft. service ceiling. However, according to the climb profiles in the crew's flight manual, the maximum altitude for the 500-ft.-per-minute climb the pilots set was only 38,700 ft., based on the atmospheric conditions and the aircraft's weight that night.
By operating outside the airplane's performance envelope, Rhodes and Cesarz subjected the engines to tremendous stress. The flight data recorder shows that soon after the crew ignored the fourth stall warning, the core temperature of the right engine reached 2200 degrees--almost 600 degrees above redline.
When investigators pulled apart the right engine, they found that the ends of the high-pressure turbine blades had liquefied, resolidifying on the low-pressure blades behind them. This leads some industry experts to question if the right engine ever could have restarted.
Whether the left engine locked up is still being investigated. GE helped the NTSB disassemble Flight 3701's engines. Edward Orear, GE's former program manager for the CF34-3B1 engine, testified to the NTSB that neither engine showed evidence of core lock.
THE OBJECT LESSON
The data recorder shows that the pilots failed to follow proper procedures for restarting a flamed-out engine when they pulled out of their dive before reaching the necessary speed to spin the core. Whether the apparently undamaged left engine could have restarted if they had windmilled correctly may never be known. It's also unresolved why the left engine didn't restart when the pilots used the APU.
Since the crash, Pinnacle has set a ceiling of 37,000 ft. for all CRJ200 flights. It has also added detailed climb profiles to the pilots' quick reference guides. And the airline has modified its simulator training program, incorporating dual engine failure and stall recovery scenarios.
Although Flight 3701 ended tragically, it illustrates how many safety features protect commercial passengers. The crew misused the auto-pilot, took the plane outside its envelope and repeatedly overrode the safety system. As one pilot told PM: "It's an object lesson in how many things you have to get wrong in order to crash your plane."
Links referenced within this article
taped cockpit conversations
http://www.popularmechanics.com/specials/what_went_wrong/1958917.html
http://media.popularmechanics.com/documents/WWWrong106.pdf
Find this article at:
http://www.popularmechanics.com/science/aviation/2156137.html
'We don't have any engines'
Two joyriding pilots took a jet to its 41,000-ft. ceiling--and paid for the stunt with their lives. PM investigates the crash of Flight 3701.
BY JIM GORMAN
Published in the January, 2006 issue.
For three and a half minutes on the night of Oct. 14, 2004, Capt. Jesse Rhodes and First Officer Peter Cesarz were on top of the world. The two Pinnacle Airlines pilots had pushed their twin-engine, 50-seat regional jet to its maximum altitude and were now proud members of the "410 club," an unofficial society of Pinnacle airmen who've attained 41,000 ft. in a Bombardier CRJ200.
Rhodes went to the galley to grab cold Pepsis to celebrate. He was barely settled back in the cockpit when the plane's radio crackled. "Are you a RJ [regional jet] 200?" inquired an air traffic controller in Olathe, Kan. "I've never seen you guys up at forty-one there."
"Yeah ... we don't have any passengers on board so we decided to have a little fun and come on up here," Rhodes replied.
The fun was short-lived. Moments later, both engines flamed out.
The fate of Flight 3701 is the subject of an intensive investigation by the National Transportation Safety Board (NTSB), which is expected to issue a final report on the accident in the next few months. Until then, neither Pinnacle Airlines, which operates connecting flights for Northwest Airlines, nor Bombardier and General Electric--the airplane and engine manufacturers--can comment on the cause of the accident. However, the pilots' taped cockpit conversations and preliminary hearings last June suggest a scenario involving poor judgment, insufficient training and the complications that can occur when a plane is pushed beyond its capabilities.
TO THE LIMIT
Rhodes, 31, and Cesarz, 23, were on what pilots call a deadhead, transferring an empty plane overnight from Little Rock, Ark., to Minneapolis so it could be ready for a morning flight. The Canadian-built CRJ200 is Pinnacle's workhorse, making short and midrange hops mostly in the Midwest. From wheels-up, it was clear that Rhodes and Cesarz intended to see what the CRJ200 could do.
Four seconds after takeoff at 9:21 pm, the two pilots did a "pitch up" maneuver that pinned them in their seats with 1.8 g's of force and momentarily triggered an alert from the airplane's stall warning system.
Minutes later, Rhodes and Cesarz again yanked back on the control column, rocketing the plane upward and generating over 2.3 g's of force before they eased off the flight controls. After briefly leveling off at 37,000 ft., the crew set the autopilot to climb at 500 ft. per minute--more than twice the fastest recommended rate--to the airplane's maximum altitude of 41,000 ft.
As the plane rose, it succumbed to the physics of high-altitude flight: Thin atmosphere offers less lift and robs the engine of air. Stuck in an aggressive climbing mode, Flight 3701's speed began to drop. To maintain the rate of climb, the autopilot angled the nose of the aircraft up, slowing it further. By the time the aircraft reached 41,000 ft. and leveled off, it was flying slowly, at 150 knots indicated airspeed, and was perilously close to losing aerodynamic lift--or stalling.
"This thing ain't gonna [expletive] hold altitude," Cesarz said.
"It can't man," Rhodes replied. "We [cruised/greased] up here but it won't stay."
The combination of high altitude and low speed once again triggered the Bombardier's stall warning system. First, "stick shakers" rattled the control columns and disengaged the autopilot to alert the crew of an imminent stall. When the crew didn't lower the plane's nose to gain speed, "stick pushers" forced the control columns forward. The flight data recorder shows that Rhodes and Cesarz overrode the stick pushers three times and forced the plane's nose back up. At 9:55 pm, as they pulled up for the last time, both engines flamed out.
"We don't have any engines," one of the pilots said.
FAILED EFFORTS
While the altimeter spun downward, the crew hurriedly reviewed their options for restarting the engines. At that altitude, there were six suitable airports within reach for a forced landing. Despite the serious nature of their predicament, the pilots did not notify air traffic control (ATC) of their situation or request emergency landing clearance.
First, they tried a "windmill restart" by diving to increase airspeed. The maneuver is intended to force air into the engine housing, spinning the rotors and creating enough compression for ignition. The procedure requires at least 300 knots of airspeed. But at 20,000 ft. and only 236 knots, the crew pulled up, and decided instead to try a second option: Drop to 13,000 ft. and attempt to relight the engines using the plane's auxiliary power unit (APU), which generates pneumatic pressure to spin the engine's core.
Rhodes and Cesarz tried at least four times to jumpstart the engines using the APU. On each attempt the engine cores recorded no rotation.
At 10:03 pm, the crew radioed ATC that they had a single engine failure. Five minutes later, at an altitude of 10,000 ft., and descending at 1500 ft. per minute, Rhodes and Cesarz were running out of options for restarting the engines. Finally, 12 minutes after the twin flameout, they revealed to ATC that they had a double engine failure. The plane's landing choices were now limited to two airports.
With the runway lights of Jefferson City airport in sight, but altitude slipping away, Rhodes and Cesarz realized they were in big trouble.
"Dude, we're not going to make this," Rhodes said. "We're gonna hit houses, dude."
They crashed 2-1/2 miles shy of the runway--behind a row of houses. On impact, the plane split apart, flipped over and caught fire. Rhodes and Cesarz were killed. Miraculously, no one on the ground was injured.
THE INVESTIGATION
An area of contention during the NTSB hearings about Flight 3701 has been whether a condition called "core lock" contributed to the fatal crash. Under normal conditions, the rotating parts inside a General Electric CF34-3B1 turbofan engine slip by each other in a finely tuned choreography.
However, when an engine is shut down suddenly at high torque, high altitude, and it isn't restarted immediately, metal parts inside the engine begin to cool and contract at different rates. In rare cases, metal can contact metal and prevent the core from rotating freely--core lock.
The Air Line Pilots Association suggests that core lock, rather than pilot error, might have been the primary cause of the accident. But, a review of the flight data recorder makes clear that the pilots made a series of poor, and potentially fatal, decisions irrespective of whether the engines experienced core lock.
The Bombardier has a 41,000-ft. service ceiling. However, according to the climb profiles in the crew's flight manual, the maximum altitude for the 500-ft.-per-minute climb the pilots set was only 38,700 ft., based on the atmospheric conditions and the aircraft's weight that night.
By operating outside the airplane's performance envelope, Rhodes and Cesarz subjected the engines to tremendous stress. The flight data recorder shows that soon after the crew ignored the fourth stall warning, the core temperature of the right engine reached 2200 degrees--almost 600 degrees above redline.
When investigators pulled apart the right engine, they found that the ends of the high-pressure turbine blades had liquefied, resolidifying on the low-pressure blades behind them. This leads some industry experts to question if the right engine ever could have restarted.
Whether the left engine locked up is still being investigated. GE helped the NTSB disassemble Flight 3701's engines. Edward Orear, GE's former program manager for the CF34-3B1 engine, testified to the NTSB that neither engine showed evidence of core lock.
THE OBJECT LESSON
The data recorder shows that the pilots failed to follow proper procedures for restarting a flamed-out engine when they pulled out of their dive before reaching the necessary speed to spin the core. Whether the apparently undamaged left engine could have restarted if they had windmilled correctly may never be known. It's also unresolved why the left engine didn't restart when the pilots used the APU.
Since the crash, Pinnacle has set a ceiling of 37,000 ft. for all CRJ200 flights. It has also added detailed climb profiles to the pilots' quick reference guides. And the airline has modified its simulator training program, incorporating dual engine failure and stall recovery scenarios.
Although Flight 3701 ended tragically, it illustrates how many safety features protect commercial passengers. The crew misused the auto-pilot, took the plane outside its envelope and repeatedly overrode the safety system. As one pilot told PM: "It's an object lesson in how many things you have to get wrong in order to crash your plane."
Links referenced within this article
taped cockpit conversations
http://www.popularmechanics.com/specials/what_went_wrong/1958917.html
http://media.popularmechanics.com/documents/WWWrong106.pdf
Find this article at:
http://www.popularmechanics.com/science/aviation/2156137.html
