The Four One Zero Club: The crash of Pinnacle Airlines flight 3701
On the 14th of October 2004, a CRJ-200 regional jet was on a positioning flight to Minneapolis without passengers when the pilots decided to test the capabilities of their airplane, apparently for fun. They climbed to the plane’s service ceiling in order to join the so-called “410 club,” but as they struggled to keep the jet at this extreme altitude, they pushed it beyond its limits. The plane stalled and both engines flamed out, leaving the pilots with few options and even less time. They scrambled to find a solution, but the engines refused to restart, and the plane crashed to earth in a residential neighborhood in Jefferson City, Missouri, killing both crewmembers. As the National Transportation Safety Board unraveled the sequence of events, it became clear that this was one of the most unusual accidents in recent memory. For some reason, two trained pilots took a passenger jet on a joyride and flew it until it broke. How could they have done such a thing? And why weren’t they able to avert the clearly preventable crash? The answers would turn out to be surprisingly complicated.
Pinnacle Airlines was one of several names used by a regional carrier which offered connecting flights for Northwest and later for Delta. Founded in 1985 as Express Airlines I, it operated Northwest Airlink flights under a code-sharing agreement for more than a decade before becoming a wholly owned subsidiary of Northwest Airlines in 1997. From then on the airline changed its name multiple times, to Pinnacle Airlines in 2002 and then to Endeavor Air in 2012, after Northwest merged with Delta (if you fly Delta Connection in the Midwest, this is probably the company operating your flight). By the early 2000s, Pinnacle’s entire fleet consisted of over 100 Bombardier CRJ-200 regional jets, which were capable of carrying about 50 passengers.
But passenger jets don’t always fly with passengers on board. Sometimes an airline has to move a jet from one city to another for scheduling purposes, and this is what happened to one of Pinnacle’s CRJ-200s on the night of the 14th of October 2004. A previous crew in Little Rock, Arkansas had rejected the plane due to a mechanical issue, and it was taken in for maintenance for several hours so technicians could fix the problem. After the work was complete, however, Pinnacle still needed to get the plane to Minneapolis-St. Paul International Airport to fulfil its next scheduled flight. This ferry flight to the Twin Cities was to be conducted without passengers under Part 91 of the federal aviation regulations, which applies to private, non-revenue flights. The only people on board would be the two pilots, 31-year-old Captain Jesse Rhodes and 23-year-old First Officer Peter Cesarz. The two were known as competent pilots, and Rhodes had nearly 7,000 flying hours, although Cesarz was new to the CRJ-200.
At 9:21 p.m. local time, Pinnacle Airlines flight 3701 took off from Little Rock Airport and headed north toward Minneapolis. Several hours of boring night flying lay ahead of the crew — but they had no intention of being bored. It was an open secret among pilots at Pinnacle Airlines that Part 91 ferry flights were a great opportunity to have fun testing the capabilities of the nimble and sporty CRJ-200, and this is what Rhodes and Cesarz apparently decided to do that night. Shortly after takeoff, Captain Rhodes hauled back sharply on the controls, putting the plane into a zoom climb that subjected them to nearly twice the force of gravity. The plane only levelled off after losing considerable speed, triggering a stall warning and eventually the stick pusher, a safety system which automatically pushed the nose down to prevent the plane from stalling. After that, the climb was normal until an altitude of about 15,000 feet, where the pilots decided to switch seats — the captain in the right and the first officer in the left. With First Officer Cesarz now flying the plane, they pitched steeply upward once again, pulling 2.3 G’s and briefly achieving a climb rate of 10,000 feet per minute. This was followed by several large rudder inputs alternating between left and right. Although the cockpit voice recording had not yet begun and the exact reasons for these maneuvers cannot be known with certainty, it is thought that the pilots were experimenting with the full range of the jet’s performance, in blatant violation of basic professional standards.
At 9:35, the captain called the regional air traffic controller and requested permission to climb to 41,000 feet. 41,000 feet, or flight level 410, is the service ceiling of the CRJ-200, the highest altitude at which it can safely fly. The aircraft is rarely ever flown at this altitude, as operational reasons to do so are few. But at Pinnacle Airlines, pilots had created an informal group called the “410 club,” consisting of those pilots who had pushed the jet to its service ceiling, almost always on Part 91 ferry flights where no one was watching. Neither Rhodes nor Cesarz had joined the 410 club, and tonight they saw an opportunity to rectify that by taking their empty aircraft up to 41,000 feet over rural Missouri. The controller soon granted their request, and the plane began to climb.
Above about 37,000 feet, special care needs to be taken to keep the plane’s energy state within an increasingly narrow band of safe parameters. The minimum climb speed at these altitudes for the CRJ-200 was 250 knots (463 km/h); the resultant rate of climb was not allowed to be less than 300 feet per minute, or the plane would have to be leveled off. The empty jet was perfectly capable of meeting these guidelines, but instead of selecting a speed of 250 knots or greater and letting the plane climb at whatever rate resulted, the pilots selected a climb rate of 500 feet per minute and left airspeed as the dependent variable — a figure that would prove to be too high under the circumstances.
When operating at high altitudes, a mathematical concept called the “power curve” comes into play. The power curve is a parabolic line with airspeed on the X-axis and engine power on the Y-axis, marking the amount of engine power needed to maintain a particular airspeed given a plane of a certain weight at a constant altitude. At high airspeeds, high engine power is needed to keep the plane moving fast. As airspeed drops, the amount of required engine power decreases quadratically down to an optimum airspeed, below which the amount of engine power needed to maintain a given speed begins to increase again. This is because at lower speeds (particularly at high altitudes), the plane’s angle of attack — its pitch angle relative to the airflow — must be increased in order to maintain sufficient lift. A higher angle of attack increases lift, but it also increases drag, which must be countered with increased engine power. If the airspeed drops low enough, maximum power will be insufficient to overcome the extra drag from the high angle of attack, airspeed will drop, and the angle of attack will increase further, creating a feedback loop that can only be ended by pitching down and descending to a lower altitude. This feedback zone is called the “back side of the power curve,” and in order to avoid falling into it, pilots flying at high altitudes must always make sure their airspeed remains above the optimum point where the power curve reverses direction.
Ascending from 37,000 feet to 41,000 at a climb rate of 500 feet per minute was not sustainable — the only way to maintain this rate was to pitch up to a higher angle of attack, increasing lift but decreasing airspeed. At the beginning of the climb, their airspeed was only 203 knots, well below the 250 knots required to stay ahead of the power curve, but the pilots made no mention of this fact during the climb. Instead, they joked excitedly about the exigencies of climbing to this unusually high altitude. The cockpit voice recording began when the flight reached an altitude of about 39,000 feet, where it captured their childlike revelry.
“Look at that fucking fuel flow man!”
“Ah shit dude, they’re both almost under a thousand and flying in climb, that’s unreal!”
“That shit’s crazy!”
At 9:48, First Officer Cesarz revealed the reason behind their climb. “Man, we can do it,” he said. “Forty-one it!”
“Forty thousand, baby!” said Rhodes.
“Look at that cabin altitude, man!”
“We’ve saved a ton of fucking fuel.”
At last, the plane reached 41,000 feet, and Cesarz leveled off, commanding the autopilot to maintain altitude. “There’s four-one-oh, my man!” he said. “Made it, man! This is great!”
As the pilots celebrated their achievement with rambunctious laughter, they remained unaware that the reality of their situation was far from “great.” By the time they arrived at 41,000 feet, their airspeed had dropped to 163 knots, putting them deep in the back side of the power curve. In order to keep enough lift to maintain 41,000 feet at such a low airspeed, the autopilot had to increase their angle of attack, which caused airspeed to drop further, necessitating a further increase in angle of attack, and so on. With the engines already at max power, they couldn’t add more energy to stop the feedback loop; they would either have to descend, or the plane would eventually slow down too much and stall.
But neither pilot had caught onto the problem yet. At 9:52, Rhodes asked, “Want anything to drink?”
“Aw yeah actually, I’ll take a Pepsi,” said Cesarz.
“A Pepsi?” said Rhodes. “I thought you said a beer, man. Yeah I’d like one too, haha.”
“Is that seal on the liquor cabinet?” Cesarz joked.
Rhodes got out of his seat, in violation of standard procedures, to go back and get the sodas. About 15 seconds later, he returned.
“This is the greatest thing, no way!” said Cesarz.
“You want a can or you want a cup?” Rhodes asked. “We don’t have any ice.”
“They’re cold as fuck my dude.”
After popping open their Pepsis in what can only be considered the grimmest example of product placement in aviation history, they settled in to check out their instrument readings.
“Accelerating up at all?” Rhodes asked.
“It ain’t speeding up worth shit,” said Cesarz.
“Look how high we are,” Rhodes commented. “This fucking nose is — look at how nose high we are.” For the first time, it seemed to be dawning on them that their situation was not entirely stable.
At 9:53, the air traffic controller spotted the jet at 41,000 feet and was taken aback. “Flagship thirty-seven-zero-one, are you a RJ-200?” he asked.
“Thirty-seven-zero-one, that’s affirmative,” Captain Rhodes replied.
“I’ve never seen you guys up at forty one there,” said the controller.
“Yeah, we’re actually ah — we don’t have any passengers on board so we decided to have a little fun and come on up here.”
“This is actually our service ceiling,” Rhodes added. Turning back to his first officer, he said, “Damn thing’s losing it. We’re losing here. We’re gonna be fucking coming down in a second here, dude.” He paused. “This thing ain’t gonna fucking hold altitude. Is it?”
“It can’t, man,” said Cesarz. “We fucking greased it up here but it won’t stay.”
“Yeah that’s funny, we got it up here but it won’t stay up here.” Rhodes called the controller and said, “Yeah, it looks like we’re not even going to be able to stay up here… ah, look for maybe 390 or 370.” By this point the engines were working so hard to keep the plane aloft that the turbine blades in the number two engine literally began to melt.
Seconds later, with the speed dropping through 150 knots and the angle of attack rising past 7.5 degrees, the computer detected that the airplane was at risk of stalling and activated the “stick shaker” stall warning. Seconds later, the stall warning activated again, and this time the “stick pusher” also came online, automatically pushing the nose down to prevent the stall.
“Damn,” said Rhodes.
“I got it,” said Cesarz, pulling the nose back up and overriding the stick pusher. Over the next several seconds, the stick pusher activated two more times, and both times he manually overrode it. Predictably, the plane responded to his efforts by stalling.
As the plane stalled, its pitch angle increased to 29 degrees and the angle of attack skyrocketed until it literally went off the charts, surpassing the data recorder’s ability to measure it. The CRJ-200 lost lift and began to fall from the sky. Powerful buffeting rocked the plane as it rolled a terrifying 82 degrees to the left with its nose pointed almost straight up at the sky. The unusual attitude interrupted airflow through the engine inlets, and both engines flamed out like candles in the wind.
In between a series of “engine oil” warnings, Captain Rhodes could be heard cursing as he struggled to wrestle the plane into submission. “Declaring emergency, stand by,” Cesarz said over the radio as Rhodes rolled the plane level and pushed the nose down, skillfully forcing the plane out of the stall. But as engine power rolled back to zero, the lights went out in the cockpit, leaving only the captain’s side and standby instruments running off the emergency battery.
“We don’t have any engines,” said Cesarz.
“You’ve got to be kidding me,” said Rhodes.
At this point, the crew needed to execute the double engine failure checklist, which they were supposed to have memorized. One of the first items on this checklist was to pitch down and maintain an airspeed of at least 240 knots. On the CRJ-200, a speed of at least 240 knots was necessary to keep the engine cores rotating fast enough to later restart the engines. The reason for this minimum, which was not explained in the checklist, was that the General Electric CF-34 engines used on the CRJ-200 were vulnerable to a rare phenomenon called “core lock.” After a high altitude engine failure, hot engine components would cool at different rates, which sometimes caused the high pressure compressor section to bind against an air seal, preventing the engine core from rotating. However, this would not happen if the core never stopped rotating in the first place. The airspeed of 240 knots was designed to be fast enough that air rushing in through the engine inlet would keep the core rotating at a high enough rate to prevent core lock. But for some reason the pilots weren’t following the dual engine failure memory items, and, unaware of the critical reason behind this minimum, they allowed their speed to drop to 200 knots without any attempt to accelerate.
The next step was to relight the engines using a “windmill restart” technique. But it was not until 10:00, 79 seconds after they first recognized the dual engine failure, that Captain Rhodes began instructing First Officer Cesarz on the windmill restart procedure. The procedure first involved accelerating to 300 knots to spin up the engine cores. “Okay actually, push the nose over,” Rhodes said. “Push it over, let’s get to 300 knots.” But Cesarz pushed the nose down so timidly that their airspeed only increased to 236 knots before dropping again. Rhodes didn’t step in to correct him.
About a minute later, Rhodes checked his instruments and saw that there was no core rotation occurring. In light of this fact, he decided to try a different engine relight procedure instead: an APU bleed air start. This technique involves starting the engines like they would normally be started on the ground, by using the auxiliary power unit to pump air through the engine cores to get them rotating. But this was only possible below 13,000 feet where the air was denser. At that point they were still well above 20,000 feet, so they decelerated to the optimal glide speed of 170 knots and prepared to wait until they descended low enough to try an APU restart. The controller asked for the nature of their emergency, to which Rhodes replied, “Ah, we had an engine failure up there at altitude, uh… airplane went into a stall and one of our engines failed… so we’re gonna descend down now to start our other engine.” Incredibly, by stating that only one engine had failed, Rhodes was lying to the controller about the nature of their emergency in order to obscure the true consequences of their reckless behavior.
Beginning at 10:07, the crew attempted several times to perform the APU restart procedure, but all four attempts failed. The shutdown of the engines at a high power setting had thrust their extremely hot internal components into the bitter subzero air temperatures at 41,000 feet, causing parts to cool at different rates, as described earlier. The pilots’ failure to ensure the engine cores kept rotating during the descent allowed this thermal shock to lead to core lock. With the cores jammed in place, there was no way to restart either engine in the air, and they would be forced to make an emergency landing without power. Only now, five minutes after explaining to the controller that they lost an engine, did they tell her the truth: they had actually lost both.
By this point, the only airport in range was Lee C. Fine Municipal Airport near the town of Lake Ozark. But neither the pilots nor the controller knew their actual range. Flight 3701 had already flown past Lee C. Fine and would have to turn around to reach it, while the much larger airport in Jefferson City, the state capital, was only slightly farther away and almost dead ahead. As a result, the controller cleared flight 3701 to fly to Jefferson City, and the pilots agreed, unaware that without engine power they would be unable to make it to the runway.
Gliding downward through the darkness, the pilots searched desperately for the airport, pleading with the controller for information about its location. 12 miles ahead… 8 miles… at last the airport hove into view, but it was apparent that it was too far away. “Dude, we’re not gonna make this damn thing,” said Rhodes.
“Think we’re okay?” Cesarz asked.
“Where is it now? I don’t know!”
“We’re not gonna make it man, we’re not gonna make it!”
“Is there a road?” Rhodes asked. “Tell her we’re not gonna make this runway!”
Cesarz keyed his mic and asked, “We’re not gonna make the runway, is there a road?”
“TOO LOW, GEAR,” announced the robotic voice of the ground proximity warning system.
“Let’s keep the gear up, I don’t want to go into houses here,” said Rhodes.
“Damn, road right there,” said Cesarz.
“Turn to your left, turn to your left!”
“TOO LOW, GEAR! TOO LOW, TERRAIN, TERRAIN!”
“Can’t make it.”
“WHOOP WHOOP, PULL UP! WHOOP WHOOP, PULL UP!”
“Aw shit, we’re gonna hit houses dude,” said Rhodes. His were the last words heard on the cockpit voice recorder. Seconds later, the left wing impacted the top of a tree and was shorn off, sending the plane banking sharply to the left. Rolling inverted, the CRJ-200 hit several more trees and slammed into the ground upside down, tearing a fiery swathe of destruction through six residential backyards and across a suburban street. By the time the burning wreckage came to a stop, both pilots were dead, killed instantly when the cockpit slammed into the ground. Witnesses rushed to the scene to save people, but they found the plane eerily empty, with nothing but vacant seats silhouetted against the flickering light of the flames.
Emergency services soon arrived on Hutton Lane in a quiet suburb of Jefferson City, where they found a bizarre scene: an empty plane torn to pieces, surrounded by houses that it somehow failed to hit. The only structures that suffered damage were some backyard fences, and no one on the ground was hurt, leaving Rhodes and Cesarz as the sole victims of their hubris.
The National Transportation Safety Board soon arrived at the crash site, recovered the black boxes, and began the investigation into the accident. Upon listening to the cockpit voice recording, the investigators were left utterly speechless. This was not a case of a mechanical failure or pilot error — this was willful misconduct. The pilots decided to fly to 41,000 feet in order to join the 410 club, fell behind the power curve, overrode three automatic stall countermeasures, stalled their plane (causing dual engine flameout), and then failed to follow the appropriate checklist, leading to core lock which prevented them from regaining power. How on earth could a pair of professional pilots act in such a manner?
First, however, several nitty-gritty questions about the flight needed to be answered. For example: CF-34 engines were all supposed to be tested before entering service to ensure they would not experience core lock. The tests involved idling the engine for five minutes, then shutting it down at 31,000 and leaving it off for 8 and a half minutes while the plane descended at 190 knots. If the engine could then be successfully restarted, it was deemed immune to the core lock phenomenon; if not, it was sent in for a special procedure to “grind in” the troublesome seal, creating grooves that would allow the core to continue rotating instead of getting stuck. Both engines had passed the core lock test on the first try, so why did they lock up on flight 3701? The NTSB eventually determined that the abnormally high temperatures inside the engines before they failed (recall that the right engine was literally melting) combined with the exceptionally cold temperatures at 41,000 feet to produce a larger thermal shock effect that could induce core lock even in an engine which passed the more mild tests performed by General Electric.
All that aside, the pilots could have prevented the core lock by following the dual engine flameout procedures. But neither pilot made any mention of the 240-knot minimum speed prior to attempting engine relight, and when Captain Rhodes ordered First Officer Cesarz to speed up to 300 knots for the windmill restart, he didn’t comply. The NTSB theorized that the pilots botched a procedure they should have had memorized for several overlapping reasons. Most significantly, they were jolted very quickly from a joyful reverie, to a stall and aerodynamic upset, to a dual engine flameout. On top of that, the captain was sitting in the first officer’s seat and his instruments went dark when the plane lost electrical power. The result was an extremely high amount of stress applied very suddenly, an event which is known to increase the likelihood of mistakes. On top of this, the pilots were probably executing the dual engine failure checklist for the first time. While they had been made to memorize all the items on it during ground school, they never practiced it in the simulator, so the actual circumstances in which they needed to apply it differed massively from those under which they had memorized it — a fact which also increased the probability of errors. Regarding Cesarz’s failure to accelerate to 300 knots, investigators noted that he was new to the airplane and had almost certainly never pitched a CRJ-200 to the 8–10 degrees nose down required to reach that speed. His hesitance to make such a large nose down input likely led him to undercontrol the airplane, explaining his failure to reach the required speed. The fact that Captain Rhodes didn’t immediately take over the plane and pitch down himself suggests that he had not achieved full situational awareness.
Another point that needed addressing was why the pilots overrode the stick pusher three times, allowing the plane to stall. Investigators noted that neither pilot had been trained in high-altitude stalls; rather, they were trained in low-speed, low-altitude stalls, because these are the most common type. A stall at low altitude can often be prevented by accelerating the engines and leveling the plane as soon as the stick shaker warning is activated. Although the pilots would have known in theory that a high altitude stall can be prevented only by pitching down to gain speed, investigators suspected that the pilots could have been attempting to perform the low-altitude stall recovery procedure instead. Without special training in high-altitude stalls, their instinctive reaction to a stall warning might have been to level off and accelerate to max power. But the engines were already at max power and the plane was already flying level. By making these inputs, they simply overrode the stick pusher that was trying to force them to descend, and allowed the plane to stall. This suggested that neither pilot was aware of the plane’s energy state. Ever since leaving 37,000 feet, flight 3701 had been on the back side of the power curve, with ever-increasing angle of attack and ever-decreasing airspeed, and a stall was inevitable if they didn’t descend. Had they followed proper procedures and set a target airspeed instead of a target rate of climb, they would have been able to fly at 41,000 feet without any trouble, but they did not. Although the pilots did comment that the plane didn’t want to stay at 41,000 feet, their subsequent actions showed that they never figured out their position on the power curve.
The third operational matter which the NTSB considered was whether the plane could have reached an airport. Investigators found that at the optimal glide speed, no less than six airports were in range at the time of the upset, including Jefferson City (although this one was the furthest away). Had the pilots immediately told the controller that they had lost both engines, the controller would have swiftly guided them to the nearest available airport. Instead, they waited until their only option was a small municipal airport that was already behind them and which did not present itself to the controller as an obvious destination. By that point Jefferson City was out of range. The pilots’ decision to deliberately deceive the controller in an attempt to hide the extent of their recklessness thus deprived them of numerous opportunities to make a safe landing.
The final and most important matter examined by the NTSB was the pilots’ extremely unprofessional behavior during the entire course of the flight. While their failure to follow checklists and poor understanding of the aircraft’s energy state contributed to the outcome, none of it would have mattered if the pilots hadn’t decided to take their jet on a joyride through the skies over Missouri. Neither pilot was incapable of flying safely; in fact, Captain Rhodes was a graduate of the prestigious Embry-Riddle Aeronautical University, had worked as an instructor there after graduating, and was described as a capable pilot by most people who knew him. (Few had anything negative to say about the young first officer either.) But while Rhodes was universally praised for his stick-and-rudder flying skills (exemplified by his quick recovery from the stall), at least one instructor did note that critical thinking and judgment were his weakest areas.
Those deficiencies may have left him particularly susceptible to a culture at Pinnacle Airlines which rewarded risky behavior. Enough pilots had already pushed their CRJ-200s to 41,000 feet to establish an informal “410 club,” which helped normalize deviant behavior on Part 91 ferry flights without passengers. Further contributing to this cultural problem was a key principle of Situational Control Theory, which holds that “the chance that someone will violate a rule increases when such a violation results in personal achievement and is likely to go undetected.” A senior pilot at another regional airline agreed, testifying at an NTSB hearing that “repositioning flights seemed to bring out the worst in their company’s pilots.” Flight data recorder readouts at this other airline showed that pilots frequently used ferry flights to attempt extreme maneuvers such as steep climbs, descents, and bank angles. Clearly this was a problem that existed in many regional airlines throughout the United States.
As a result of the accident, Pinnacle Airlines introduced widespread reforms, including simulator training on high-altitude engine failures, and a program to monitor FDR data to detect joyriding on ferry flights. Bombardier and Pinnacle Airlines also rewrote the CRJ-200 dual engine failure checklist to explain the consequences of failing to maintain at least 240 knots, to clearly indicate that a 300 knots was the absolute minimum airspeed for a windmill restart, and to explain that a large pitch down would be necessary to achieve this speed.
On top of these changes, the NTSB also recommended that airlines provide more comprehensive training on the high-altitude capabilities of regional jets; that airlines be required to provide training in high-altitude stalls; that all CRJ-200 operators incorporate the aforementioned checklist changes; that regional airlines more proactively encourage and monitor professional conduct on non-revenue flights, including through examinations of FDR readouts; that pilots’ unions provide educational materials referencing recent accidents caused by unprofessional behavior; that General Electric test CF-34 engines for core lock at high altitudes and power settings; that pilots be made aware of the possibility of core lock and how to prevent it; and several other recommendations.
The findings of the Pinnacle Airlines investigation still inspire much shock and head-shaking in the aviation industry. In its final report, the NTSB excoriated the pilots for their reckless behavior, describing it with phrases like “thrill-seeking,” “not consistent with the degree of discipline, maturity, and responsibility required of professional pilots,” “unprofessional operation,” and “willful misconduct.” They flew their jet like a stunt plane, laughed and cursed like a pair of friends out at a bar, and violated procedures left and right. While it’s sad that they lost their lives, their actions must stand as a cautionary tale. In order to amplify that message, Rhodes and Cesarz were among the 2004 recipients of the infamous Darwin Awards, a tongue-in-cheek website which hands out recognition to people who “remove themselves from the gene pool” through their own idiotic actions. The safety benefits of this publicity may be as great or greater than any of the NTSB’s recommendations: with most US pilots aware of the tragic fate of Captain Jesse Rhodes and First Officer Peter Cesarz, and the ridicule which they and their families had to endure after their deaths, few are likely to want to follow in their footsteps.
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