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=== Power curve ===

=== Power curve ===

{{further|Drag curve#Power required curves}}

{{further|Drag curve#Power required curves}}

The power curve relates the [[airspeed]] of an aircraft in level flight to the engine [[thrust]] available. On a graph with airspeed on the x-axis and thrust available on the y-axis, the power curve is an [[parabola]] opening upward where a given thrust is required to maintain a certain airspeed. “Falling behind the power curve” is a situation that can happen when an aircraft flies slower while maintaining the same altitude.<ref>{{cite web |last1=Horne |first1=Thomas A. |title=Proficiency: Behind the Power Curve |url=https://www.aopa.org/news-and-media/all-news/2013/november/pilot/proficiency-behind-the-power-curve |publisher=[[Aircraft Owners and Pilots Association]] |access-date=October 25, 2025 |date=November 5, 2013}}</ref> In order to maintain the same altitude, an aircraft must maintain constant [[lift (force)|lift]],

The power curve relates the [[airspeed]] of an aircraft in level flight to the engine [[thrust]] available. On a graph with airspeed on the x-axis and thrust available on the y-axis, the power curve is an [[parabola]] opening upward where a given thrust is required to maintain a certain airspeed. the aircraft the .<ref>{{cite web |last1=Horne |first1=Thomas A. |title=Proficiency: Behind the Power Curve |url=https://www.aopa.org/news-and-media/all-news/2013/november/pilot/proficiency-behind-the-power-curve |publisher=[[Aircraft Owners and Pilots Association]] |access-date=October 25, 2025 |date=November 5, 2013}}</ref> to the same altitude maintain constant [[lift (force)|lift]],

== Accident ==

== Accident ==

2004 aviation accident in Missouri

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. 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, 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 on board made the aircraft climb to 41,000 ft (12,000 m), the maximum operating altitude of the CRJ200 but did not ensure a safe airspeed for the high altitude they were flying at. Due to the low energy state of the aircraft, it subsequently stalled and due to interrupted airflow, both engines 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 that led to the accident. During the flight, they found that the crew had intentionally deviated from standard operating procedures, basic airmanship, 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 celling 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 during the accident sequence, which prevented the crew from restarting them, and the available documentation to the crew did not communicate the importance of preventing core lock.

The aircraft involved in the accident was a Bombardier CRJ200, registered as N83696A. 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.[2] The aircraft was powered by two General Electric CF34-3B1 turbofan engines. The service celling of the CRJ200 is 41,000 ft (12,000 m).[4] Flight crew operating manuals from Pinnacle Airlines instructed crews flying above 36,000 ft (11,000 m) to maintain a minimum climb speed of 250 kn (460 km/h) and a rate-of-climb of at least 300 ft/min (91 m/min).

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.[6] 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.[8] 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.

At the time of the accident, Pinnacle Airlines was a regional airline and subsidiary of Northwest Airlines.[10] The airline was initially founded in 1985 as Express Airlines I with turboprop aircraft only. In 2001, the airline began to expand its fleet with CRJ aircraft 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.[13] 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 the altitude were not demonstrated in simulator training. 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 informal club of Bombardier CRJ pilots who had flown the aircraft up to its service celling of 41,000 ft (12,000 m) or flight level 410, informally referred to as the “410 club”.[6][8][16] Testimony of pilots who climbed to flight level 410 indicated that these climbs were conducted on repositioning flights.[17] 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.[17]

The power curve relates the airspeed of an aircraft in level flight to the engine thrust available. On a graph with airspeed on the x-axis and thrust available on the y-axis, the power curve is an parabola opening upward 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 parasite drag increases.[19] “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.[20] 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.[21]

Pre-flight and takeoff

[edit]

On October 14, 2004, a different Pinnacle Airlines flight crew was scheduled to fly the incident aircraft from Little Rock National Airport to Minneapolis–Saint Paul International Airport, but this crew received an error message and aborted their takeoff. Pinnacle Airlines dispatched maintenance crews to Little Rock to resolve the problem. The problem was identified and fixed. Because the aircraft was needed in Minneapolis the next morning, Flight 3701 was scheduled overnight as a repositioning flight to move the airplane from Little Rock to Minneapolis.[22]: 11 

Flight 3701 departed Little Rock at 21:21 Central Daylight Time (CDT).[a] The flight plan from Little Rock to Minneapolis indicated a planned cruising altitude of Flight Level (FL) 330, or about 33,000 feet (10,000 m).[22]: 2  After departing Little Rock, the airplane pitched up sharply several times during its ascent, briefly reaching a climb rate of 10,000 feet per minute (51 m/s).[22]: 2 

Digital illustration of Flight 3701 falling from 41,000 feet

At 21:35, Flight 3701 requested clearance to climb to 41,000 feet (12,497 m), the maximum operating altitude of the Bombardier CRJ series. Clearance was granted by air traffic control (ATC) at 21:36, and the airplane climbed to its new cruising altitude soon thereafter.[22]: 2  Air traffic control commented about the unusual altitude and the captain replied, “we don’t have any passengers on board so we decided to have a little fun and come on up here.”[22]: 3  At 21:54, the pilots began to struggle with control of their airplane. Both engines lost power and the plane’s stick shaker warned the pilots of an impending stall. The pilots declared an emergency and descended, temporarily regaining control of their aircraft at 34,000 feet (10,000 m).[22]: 4 

The pilots attempted to restart the engines but could not do so. At 22:09, Flight 3701 asked ATC to direct them to the nearest airport for an emergency landing, and the controller on duty directed them to Jefferson City Memorial Airport in Jefferson City, Missouri. At 22:14, the pilots realized they could not reach the airport and began looking for a road or highway where they could perform a forced landing.[22]: 5–6 

Around 22:14, the captain was heard on the cockpit voice recorder (CVR) stating that the gear should be up to avoid houses.[citation needed] About a minute later, the airplane crashed into the ground outside Jefferson City. Both crew members were killed, but no casualties occurred on the ground.[22]: 6 

The investigation into the accident emphasized the information contained in the flight data recorder (FDR) and the CVR.

Flight crew performance

[edit]

Investigators determined that the two pilots were exploring the performance limits of the empty CRJ-200 on the flight. The pilots decided to test the limits of the CRJ and join the “410 club,” referring to pilots who pushed CRJs to their maximal approved altitude of flight level 410 (FL410) or 41,000 feet (12,497 m) above sea level.

The accident sequence started when the pilots performed several nonstandard maneuvers at 15,000 feet (4,600 m), including a pitch-up at 2.3 g (23 m/s2) that induced a stall warning. They set the autopilot to climb at 500 feet per minute (150 m/min) to FL410. This exceeded the manufacturer’s recommended climb rate at altitudes above FL380. In the attempt to reach FL410, the airplane was pulled up at more than 1.2 g, and the angle of attack became excessive to maintain climb rate in the thinner upper atmosphere. After reaching FL410, the airplane was cruising at 150 knots (170 mph; 280 km/h) indicated airspeed, barely above stall speed, and had over-stressed the engines.

The airplane’s anti-stall devices activated while they were at altitude, but the pilots repeatedly overrode the automatic nose-down that would have increased speed to prevent stalling. After four overrides, both engines experienced flameout and deactivated. The airplane then stalled. The pilots recovered from the stall at FL380 or 38,000 feet (11,582 m) while still having no engine thrust. At that altitude, six diversion airports were within reach for a forced landing. This caused the pilots to pitch nose down in an attempt to restart the engines, which requires a dive sharp enough to attain the required 300 knots (350 mph; 560 km/h) airspeed for a windmill restart to make the blades in the turbines windmill at 10% N2 (turbine rotational speed). The captain did not perform the necessary procedure to ensure that the first officer achieved the needed airspeed or greater required for the windmill engine restart procedure and then did not demonstrate command authority by taking control of the airplane and accelerating it to at least that speed.

The crew ended the descent when they had reached 230 knots (260 mph; 430 km/h) indicated airspeed, but neither engine core (N2) ever indicated any rotation during the entire descent. Since they were too high for an auxiliary power unit (APU) start, the ram air turbine (known as an “air-driven generator” on Bombardier products) was deployed to provide electric power for the aircraft, and the crew donned oxygen masks, as the cabin slowly depressurized due to loss of pressurization air from the engines.

The crew glided for several minutes and then tried to restart engines using the APU at 13,000 feet (4,000 m). This was again unsuccessful. They then declared to ATC that they had a single-engine flameout. At this time, they had four diversion airports available to them. They lost considerable altitude while continuing unsuccessfully to attempt to restart both the left engine (two times) and the right engine (two times) for more than 14 minutes using the emergency restart procedure. Despite their four APU-assisted engine restart attempts, the pilots were unable to restart the engines because their cores had locked. Without core rotation, recovery from the double engine failure was not possible. At that time, the pilots finally declared to ATC that they had, in fact, lost both engines.

The NTSB also determined from FDR information that the turbofan jet engine (General Electric CF34-3B1) engine 2 turbine was operating at 300 °C (540 °F) above the maximal redline temperature of 900 °C (1,650 °F) at 41,000 feet (12,497 m). Engine 1 HPT stayed 100 °C (180 °F) below the redline.

Training and oversight

[edit]

On January 9, 2007, the National Transportation Safety Board issued its final report on Flight 3701, which concluded that the probable causes of the accident were:

  • The pilots’ unprofessional behavior, deviation from standard operating procedures, and poor airmanship.
  • The pilots’ failure to prepare for an emergency landing in a timely manner, including communicating with air traffic controllers immediately after the emergency about the loss of both engines and the availability of landing sites.
  • The pilots’ improper management of the double engine failure checklist.[22]
The wreckage of N8396A, stored in Rantoul, Kansas

Thomas Palmer, the former manager of Pinnacle Airlines’ training program, said about the crash: “It’s beyond belief that a professional air crew would act in that manner.”[23] After the accident, the airline restricted CRJ-200 flights to a maximum altitude of FL370. It also changed its training program to include ground school and simulator training in high-altitude operations.[24] In the year after the accident, each Pinnacle pilot was given simulator training up to FL410 and shown what occurred on Flight 3701.

Pinnacle Airlines was renamed Endeavor Air in 2013 after Chapter 11 bankruptcy restructuring.

  1. ^ The NTSB describes all times in its final report using Central Daylight Time.[22]: 1 

 This article incorporates public domain material from Crash of Pinnacle Airlines Flight 3701, Bombardier CL-600-2B19, N8396A, Jefferson City, Missouri, October 14, 2004 (PDF). National Transportation Safety Board. (NTSB/AAR-07/01).

  1. ^ Ranter, Harro. “Accident Canadair CL-600-2819 Regional Jet CRJ-200LR N8396A, Thursday 14 October 2004”. Aviation Safety Network. Flight Safety Foundation. Archived from the original on October 23, 2025. Retrieved October 23, 2025.
  2. ^ Webb, Phil (May 22, 2007). “NTSB determines pilots’ poor airmanship caused 2004 Pinnacle accident”. Aircraft Engineering and Aerospace Technology: An International Journal. 79 (3). Emerald Publishing. doi:10.1108/aeat.2007.12779cab.017. ISSN 1758-4213. Retrieved October 24, 2025.
  3. ^ a b “What Went Wrong: The Crash Of Flight 3701”. Popular Mechanics. January 4, 2006. Archived from the original on May 22, 2011. Retrieved January 18, 2011.
  4. ^ a b Wald, Matthew L. (June 14, 2005). “Just Before Dying, a Thrill at 41,000 Feet”. The New York Times. Washington D.C. ISSN 0362-4331. Archived from the original on January 3, 2015. Retrieved December 28, 2017.
  5. ^ Richter, Jan-Arwed (June 30, 2025). “Pinnacle Airlines Flug 3701: Als der Ehrgeiz zwei Piloten das Leben kostete” [Pinnacle Airlines Flight 3701: When ambition cost two pilots their lives]. Aero International (in German). Archived from the original on July 14, 2025. Retrieved October 23, 2025.
  6. ^ Kehaulani Goo, Sara (June 14, 2005). “Airlink Crew Pushed Jet’s Limits Prior To Crashing”. Washington Post. Retrieved October 24, 2025.
  7. ^ Wright, Chip (October 1, 2007). “Flagship 3701”. Aircraft Owners and Pilots Association. Retrieved October 23, 2025.
  8. ^ a b Polek, Gregory (January 19, 2007). “NTSB: Pinnacle crash exposes cultural, systemic safety flaws”. Aviation International News. Retrieved October 24, 2025.
  9. ^ Horne, Thomas A. (November 5, 2013). “Proficiency: Behind the Power Curve”. Aircraft Owners and Pilots Association. Retrieved October 25, 2025.
  10. ^ Singer, Neil (September 8, 2014). “Mentor Matters: The dark side of the back side”. Aircraft Owners and Pilots Association. Retrieved October 26, 2025.
  11. ^ Final Report – Accident on 24 July 2014 in the region of Gossi in Mali to the MD-83 registered EC-LTV operated by Swiftair S.A (PDF) (Report). Bureau of Enquiry and Analysis for Civil Aviation Safety, Mali Commission of Inquiry. April 22, 2016. p. 74. Archived (PDF) from the original on November 5, 2016. Retrieved October 26, 2025.
  12. ^ a b c d e f g h i j Cite error: The named reference NTSB AAR-07-01 Final Report was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference NYT 07.14.05 Thrill was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference PM 01.05.06 WWW was invoked but never defined (see the help page).

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