On October 14, 2004, Pinnacle Airlines Flight 3701, a Bombardier CRJ200 on a repositioning flight from Little Rock to Minneapolis, crashed while attempting an emergency approach to Jefferson City Memorial Airport in Missouri, United States. Both pilots, the only two people on board, were killed. The aircraft was originally scheduled to fly a passenger flight from Little Rock to Minneapolis earlier that day, but a mechanical issue forced the flight to be delayed. Since the aircraft was still needed for Pinnacle Airlines operations out of Minneapolis the next day, the airline elected to ferry the aircraft to Minneapolis. The two pilots made the aircraft climb to 41,000 ft (12,000 m), the maximum operating altitude of the CRJ200. Due to the weight of the aircraft at that altitude, the thrust available could not maintain the required airspeed. Due to the low energy state with maximum power, it slowly slowed down and subsequently stalled, resulting in turbulent airflow to both engines, which flamed out. The crew failed to execute the proper dual engine failure checklists and did not glide the aircraft to a suitable airport. The plane crashed in a residential area short of the runway and was destroyed.
The investigation, conducted by the National Transportation Safety Board, found several factors led to the accident. Investigators found that during the flight the crew had intentionally deviated from standard operating procedures, displayed unprofessional cockpit attitude, and aggressively maneuvered the aircraft. In particular, investigators discovered that Pinnacle Airlines flight crews had expressed curiosity in flying at the CRJ200's service ceiling and pilots who had done so informally called it the "410 club". Data from the flight recorders indicated that the crew did not anticipate the upset and improperly executed the checklist procedures. The crew did not effectively communicate with air traffic control about their emergency situation and did not fully discuss potential landing sites. Investigators also determined that the engines core locked prior to the accident, which prevented the crew from restarting them, and the available documentation provided to the crew did not communicate the importance of preventing core lock.
Background
Aircraft
The aircraft involved in the accident was a Bombardier CRJ200, registered as N8396A. By the time of the accident, it had a total of 10,168 airframe hours and 9,613 flights. Pinnacle Airlines acquired the airframe in May 2000, soon after it was manufactured. The aircraft was powered by two General Electric CF34-3B1 turbofan engines. The certified maximum operating altitude of the CRJ200 is 41,000 ft (12,000 m). The aircraft was equipped with an auxiliary power unit (APU), which provides power to the aircraft when the engines are not operating. An engine restart can be conducted by using bleed air from the APU to rotate the engine core. The Bombardier CRJ200 is equipped with a stick shaker, which warns the crew of an impending stall, and a stick pusher, which pitches the aircraft down to prevent a stall.
Crew
On the day of the accident, the aircraft was operating a repositioning flight flown by two pilots. The captain was 31-year-old Jesse Rhodes. Rhodes graduated from the Embry–Riddle Aeronautical University in Florida in 1995 and began working as a flight instructor there between 1996 and 1999. He was hired by Pinnacle Airlines in February 2004. By the time of the accident, he had a total of 6,900 flight hours, 973 of which were on the CRJ. Pilots who had previously flown with Rhodes had given favorable comments to him and the simulator instructor responsible for his upgrade training stated that he flew the plane "just fine" but noted deficiencies in critical decision-making and judgement.
The first officer of the flight was 23-year-old Peter Cesarz. Cesarz began training to become a first officer in October 2002 and was hired by Pinnacle Airlines in April 2004. By the time of the accident, he had accumulated 761 flight hours in total, 222 of which on the CRJ. Captains who had flown with Cesarz described him as a confident pilot and a simulator instructor stated that he had a positive attitude.
Operator
At the time of the accident, Pinnacle Airlines was a regional airline and subsidiary of Northwest Airlines. The airline was initially founded in 1985 as Express Airlines I with turboprop aircraft only. The airline began to expand its fleet with CRJ aircraft in 2001, and changed its name to Pinnacle Airlines the following year. At the time of the accident, the airline employed approximately 900 pilots and had a fleet of 110 CRJ aircraft. Pinnacle Airlines was doing business as (d/b/a) Northwest Airlink, the regional commuter service for Northwest Airlines. The airline gave training on upsets, high-altitude climbs, dual engine failures, stalls, and crew resource management. Training on high-altitude climbs included discussion on flight at 41,000 ft (12,000 m), but operations at this altitude were not demonstrated in simulator training. Flight crew operating manuals from the airline instructed crews flying above 36,000 ft (11,000 m) to maintain a minimum climb airspeed of 250 kn (460 km/h) and a rate-of-climb of at least 300 ft/min (91 m/min). The airline's checklist instructed crews after a dual engine failure to maintain an airspeed of 240 kn (440 km/h) before attempting an engine restart, and once at or below an altitude of 21,000 ft (6,400 m), increase the airspeed to 300 kn (560 km/h) to initiate a windmill restart. The Federal Aviation Administration's (FAA) Flight Standards District Office in Memphis, Tennessee, was responsible for overseeing Pinnacle Airlines.
At Pinnacle Airlines, there was an unofficial group of Bombardier CRJ pilots who had flown the aircraft up to its service ceiling of 41,000 ft (12,000 m) or flight level 410, informally referred to as the "410 club". Testimony of pilots who had climbed to flight level 410 indicated that these climbs were conducted on repositioning flights. Before the crash of Flight 3701, management at the airline, including the chief pilot, the vice president of safety, and the CRJ program manager, were unaware of the club's existence.
Power curve
The power curve relates the airspeed of an aircraft in level flight to the engine thrust required. On a graph with airspeed on the x-axis and thrust required on the y-axis, the power curve is an upward-opening curve where a given thrust is required to maintain a certain airspeed. In order to maintain the same altitude, an aircraft must balance thrust with drag. An aircraft requires more thrust to fly at higher airspeeds as the parasitic drag increases. "Falling behind the power curve" is a situation that can happen to an aircraft when it begins to fly slower while maintaining the same altitude. In order to maintain constant lift (and thus altitude) while decelerating, the aircraft must increase in angle of attack (AoA). The increase in AoA results in induced drag increasing. As drag increases, airspeed decreases, necessitating an even higher AoA to maintain altitude. Therefore, more thrust would be required to maintain the high AoA at the lower airspeed. If the airspeed becomes too low and the available engine thrust falls below what is required to maintain a certain airspeed, level flight becomes impossible.
Accident
Pre-flight and departure
On October 14, 2004, N8396A was scheduled to fly from Adams Field in Little Rock, Arkansas, to Minneapolis–Saint Paul International Airport in Minneapolis, Minnesota. The crew of that flight, who were different from the accident flight, received a caution message relating to a bleed air duct fault and rejected the takeoff. However, Pinnacle Airlines still needed the aircraft in Minneapolis the following day, where the airplane's next flight was scheduled. The airline notified Captain Rhodes and First Officer Cesarz about the repositioning flight they planned the pilots to fly. The pilots arrived in Little Rock by use of deadheading on company flights and began preparing for the flight.
Flight 3701 departed Little Rock for Minneapolis at 21:21 with a flight plan that indicated a planned cruising pressure altitude of 33,000 feet (10,000 m). Five seconds after takeoff at an altitude of 450 ft (140 m), the crew conducted an abrupt pitch maneuver. The pitch of the aircraft rose to 22° nose-up and the vertical load on the airframe increased to 1.8 Gs. This resulted in the activation of the stick shaker followed soon after by the stick pusher. The pitch angle was subsequently reduced and the crew continued to climb.
Soon before 21:26 as the airplane was climbing through 14,000 ft (4,300 m), the autopilot was engaged. Captain Rhodes and First Officer Cesarz then swapped cockpit seating positions, with Rhodes sitting in the right seat and Cesarz sitting in the left seat assuming the role of pilot flying. Twenty seconds later while at 15,000 ft (4,600 m), the autopilot was disengaged and the crew once again put the aircraft into a climb and brought the nose up to 17°, exerting a load of 2.3 Gs, and resulting in a temporary climb rate of 10,000 ft/min (3,000 m/min). They then made a series of rudder inputs ranging between a left input 4.2° and a right input of 7.7°. Four minutes later at 24,600 ft (7,500 m), the crew conducted another pitch-up maneuver resulting in a 10° nose-up attitude and loading of 1.87 Gs.
Climb to 41,000 feet and upset
While the plane was at approximately 32,000 ft (9,800 m), Captain Rhodes requested permission from air traffic control (ATC) to climb to 41,000 ft (12,000 m), the service ceiling of the CRJ. After receiving clearance from ATC, the crew began to climb to 41,000 ft (12,000 m). The crew used the autopilot to conduct the climb. Rather than specifying an airspeed for the autopilot to maintain, the crew set the autopilot to vertical speed mode with a commanded rate of climb of 500 ft/min (150 m/min). The autopilot began to change the pitch of the aircraft to achieve a rate of climb of 500 ft/min (150 m/min) while the airspeed decreased from a starting value 203 kn (376 km/h).
The cockpit voice recording (CVR) began around 21:44, capturing conversation between Rhodes and Cesarz about the ongoing climb to 41,000 ft (12,000 m). The crew engaged in casual conversation and made jokes with each other. Cesarz commented to Rhodes that they were about to "41-it," to which Rhodes responded a minute later "40,000 baby". Soon before the aircraft reached 41,000 ft (12,000 m), the first officer laughed and said "There's my 41-0 man. Made it man." At 21:52, Rhodes asked Cesarz if he wanted something to drink, to which Cesarz responded that he wanted a soda. The captain left the first officer in the cockpit and came back with cans of Pepsi and joked about drinking beer. The air traffic controller monitoring the flight in Kansas City found the flight's high altitude unusual and asked the pilots whether they were flying a CRJ-200.
By 21:54, the airspeed had reduced to 150 kn (280 km/h). Rhodes commented to Cesarz that they were "gonna be ... coming down in a second here." He contacted air traffic control and requested a lower altitude, and the controller began coordinating the descent. Soon after at 21:54:36, the stick shaker activated as the AoA increased to 7.5°. Between 21:54:45 and 21:54:54, the stick shaker and stick pusher activated three times. The crew overrode the stick pusher all three times. The pitch of the aircraft varied between 7° nose up and 20° nose down. At the end of the fifth stick shaker activation and fourth stick pusher activation, the AoA increased to beyond the maximum measurable value of 27° and the pitch increased to 29°. The aircraft subsequently stalled, rolled 82° to the left, and pitched down to 32°. Both engines then flamed out.
Gliding and crash
After the aircraft stalled, the captain declared an emergency to ATC. The crew managed to execute a stall recovery maneuver and the airplane recovered from the upset at 34,000 ft (10,000 m). Shortly after, the aircraft suffered a total loss of AC power due to the failure of both engines, temporarily cutting power to the flight data recorder (FDR). The air-driven generator then deployed, supplying a limited amount of power to some aircraft systems. Among the systems powered included the left-hand side cockpit instruments, where First Officer Cesarz was seated. Captain Rhodes did not verbalize the double-engine failure until thirty seconds after the upset, and it took another minute for the crew to begin running through the checklist.
When the FDR resumed recording at 21:59 while the aircraft was passing through 29,000 ft (8,800 m), it showed that the APU was activated and supplying limited power to the aircraft. One minute later, Captain Rhodes told Cesarz to increase the airspeed to 300 kn (560 km/h), which he acknowledged. However, Cesarz did not pitch the nose down enough to increase the airspeed to 300 kn (560 km/h); the airspeed only increased to 236 kn (437 km/h) before decreasing. The captain then told the first officer that he intended to do an APU bleed air engine restart once they descended to 13,000 ft (4,000 m). At 22:03, the air traffic controller asked the crew about the nature of their emergency. Captain Rhodes lied to air traffic control, telling them that only one engine had failed and they were descending to "start our other engine". Over the next several minutes, the crew conducted four engine restart attempts using APU bleed air, all of which failed to rotate the cores. The crew members returned to their correct seat positions at 22:08.