The Last Mission: The crash of the B-17 “Nine-O-Nine”

An aerial view of the wreckage of the B-17 Nine-O-Nine after it collided with a de-icing station. (Hartford Courant)

On the 2nd of October 2019, a WWII-era B-17 Flying Fortress carrying paying passengers on a “living history” flight landed short of the runway at Connecticut’s Bradley Field. The warplane veered off to the right and crashed headlong into a de-icing station, where it burst into flames, triggering a mad rush to escape. Six people crawled from the mangled plane, but seven died in the rapidly spreading inferno. The loss of the plane and the loss of lives shocked the antique warbird community, which relied on revenues from paying passengers to keep the old bombers in airworthy condition. Everyone wanted to know: what had gone wrong?

The National Transportation Safety Board eventually found that poor maintenance and poor decision-making came together to prevent the plane from reaching the runway, despite the fact that a safe landing was possible. But the Collings Foundation, the non-profit which operated the B-17, had long been a disaster waiting to happen. The pilot who made those fatal errors was the Collings Foundation’s chief B-17 pilot and its director of maintenance, a veritable one-man army who ran the B-17 program almost single-handedly. Everything, it seemed, had fallen to this one 75-year-old man, who didn’t have time or energy to keep up with the level of safety demanded by regulations. In fact, the situation with the B-17 was symptomatic of widespread decay in safety standards throughout the Collings Foundation, which in turn arose due to shocking negligence all the way at the top, in the Federal Aviation Administration itself.

B-17s on a mission in WWII. Artwork by Stu Shepherd.

For many aviation enthusiasts, there are few things more exciting than the opportunity to ride aboard a Boeing B-17 Flying Fortress. The powerful and sturdy B-17 was the pride of the American Air Force during the Second World War, when hundreds of the four-engine bombers ran sorties throughout the European and Pacific theaters. Many were lost in battle; others returned home to be scrapped in the years after the war. But a precious few have been preserved in airworthy condition to this day, mostly by non-profit organizations that collect, display, and operate antique military aircraft — referred to in the industry as warbirds.

Warbirds are obviously not designed to carry passengers and are equipped with few, if any, of the systems that make modern airline travel so safe. But in the United States, as in many other countries, you can buy a ticket to ride on some of them, thanks to a Federal Aviation Administration rule called the Living History Flight Experience exemption. The exemption grants non-profit organizations the right to fly paying passengers on limited sightseeing flights using antique military airplanes operating under part 91 of the Federal Aviation Regulations, a set of rules normally reserved for private, non-commercial flights. The exemption also ensures that these operators don’t need to make safety upgrades that can be impossible to install on such old aircraft.

The aircraft involved in the accident, painted to resemble the original Nine-O-Nine. (Collings Foundation)

One of many organizations operating warbirds under the Living History Flight Experience exemption was the Collings Foundation, a non-profit established in 1979 to preserve antique airplanes and vehicles. Among the ten warbirds in their fleet by 2019 was a B-17 Flying Fortress built in 1945 under the military serial number 44–83575, although it had been repainted to look like its more famous sister ship 42–31909, nicknamed the Nine-O-Nine. (The original Nine-O-Nine was scrapped shortly after the end of the war.)

This particular B-17 had a long and storied history of its own, however. After WWII, it served as a search and rescue reconnaissance aircraft; was used for weapons testing by the Air Force Special Weapons command, during which time it was subjected to three nuclear explosions; was sold as scrap for $269; and was restored and flew for 10 years as a firefighting water bomber until the Collings Foundation acquired it in 1986. Having been restored to its original configuration and renamed in honor of Nine-O-Nine, the B-17 spent the next 33 years touring the country, to the delight of countless thousands of aviation enthusiasts.

Mac McCauley works on the Nine-O-Nine in Spokane sometime prior to the accident. (Spokane Spokesman-Review)

In October 2019, Nine-O-Nine was on tour again, crisscrossing America under the command of respected B-17 Captain Ernest “Mac” McCauley. The 75-year-old old McCauley was around the same age as his plane, and with over 7,000 hours logged in the Flying Fortress, he was possibly the most experienced living B-17 pilot in the world. He flew nearly all the B-17 flights for the Collings Foundation, and the brief trip out of Bradley International Airport in Windsor Locks, Connecticut on the 2nd of October was to be no different.

His first officer that day was 71-year-old Michael Foster, a veteran pilot with over 22,000 total hours but only 23 on the B-17, for which he was not type-rated (nor was he required to be). Rounding out the crew was 34-year-old Mitch Melton, an all-purpose mechanic, cabin attendant, and general helper on the job who did virtually everything except fly the plane. (For brevity’s sake, he will be referred to as the loadmaster.) McCauley, Foster, and Melton would be in charge of ten passengers, who had paid substantial sums of money for the opportunity to ride on a B-17.

Passengers board Nine-O-Nine on the day of the accident. Within an hour, half the people in this photo would be dead. (Debbie Riddell)

When the pilots tried to fire up the engines that morning, not everything went smoothly: the #3 and #4 engines — the two engines on the right side — refused to start.

The B-17 Flying Fortress predates the development of turboprop engines; instead, it is powered by four radial piston engines, which are considerably less reliable. Failures on old radial engines are a fact of life. In this case, McCauley and his crew suspected a likely cause: moisture in the magnetos. Each engine had two magnetos, which are essentially small generators that produce electricity to be distributed by the spark plugs. It had rained the night before the flight and the crew assumed water had gotten into the magnetos on engines three and four, preventing them from starting. Loadmaster Mitch Melton got out and blew compressed nitrogen through the magnetos on the affected engines, a technique he had learned from Mac McCauley.

After “blowing out the mags,” as warbird pilots called it, both engines started, and McCauley did a run-up at 1,700 rpm to check that everything was working. Apparently he was satisfied, because a few minutes later they taxied to the runway for takeoff.

Although blowing out the mags was enough to get the engines to start, the problem wasn’t just moisture: they were in poor mechanical shape as well. The magnetos on the number four (rightmost) engine were of particular concern. The left magneto’s P-lead, which connects the magneto to the cockpit switches, had over time been pulled out of its housing due to an insufficient length of safety wire on the nut that was supposed to lock it in place. This caused the P-lead to contact the magneto housing, shorting the magneto. The right magneto was in only marginally better shape, and was so worn that it produced only a weak spark in eight of the engine’s cylinders and no spark at all in the 9th. No moisture would have been needed to cause trouble starting this engine, given that it was trying to initiate combustion using the electricity produced by a single, dying magneto.

(NTSB)

Having somehow gotten the engine running, McCauley prepared to take off on the first of two sightseeing flights that day. On the air traffic control tapes, copilot Foster sounded relaxed — maybe a little bit too relaxed. When the controller asked him for his weight class (light, medium, or heavy) he replied, “Ah, we’re about 44,000 pounds… we don’t carry bombs anymore.”

At 9:47 a.m., Nine-O-Nine lifted off from runway 6 and began climbing out to the northeast. But within a minute, possibly less, it became clear that something was wrong. Due to the extremely degraded state of its magnetos, engine four was struggling to keep combustion going at a rate sufficient to maintain climb power. By the time the local control center contacted the B-17 shortly before 9:49, the pilots were already dealing with the problem, and Foster told air traffic control to “standby.”

Having concluded that the magneto was “running rough,” McCauley decided that they would need to return to the airport to troubleshoot it on the ground. He certainly didn’t think that the situation was serious. At 9:49 and 19 seconds, Foster told ATC, “Departure, ah, Boeing nine three zero one two we would like to return to the field.” By this time they were already in a right turn, preparing to come around to land on the same runway from which they departed.

“November nine three zero one two, do you need any assistance?” the controller asked.

“Negative,” said Foster. This decision might have had fatal consequences later.

“And what’s the reason for coming back?”

“We have a rough mag on number four engine and we would like to return to blow it out,” Foster replied.

On board the plane, loadmaster Melton returned to the cockpit, where he witnessed McCauley instruct Foster to lower the landing gear. Nobody knows why he chose to do this so early, but the effect of this decision would later make the difference between life and death.

Moments later, McCauley announced that he was shutting down engine four, and without consulting with Foster, he reached up, turned it off, and feathered its propeller, skipping several steps in the shutdown procedure.

Route of the plane with timestamped events. (NTSB)

In order to balance the loss of thrust on the right wing, McCauley accelerated engine three to compensate­ — but he was unaware that engine three was suffering from an equally serious problem. The electrodes in its spark plugs were too close together, which caused them to spark with excessive enthusiasm at high power settings. This resulted in premature ignition of the fuel air mixture, which manifested in the form of continuous detonations that rocked the combustion chamber. This had a serious negative effect on the engine’s power output, and if left unchecked would eventually damage the engine.

Despite the fact that both engines on the right wing were now losing power, the transmissions from the pilots gave no indication that they felt they were in an emergency situation. Foster used hedging language, telling the controller that “I kinda would like to be on the ground as soon as possible,” and neither he nor McCauley ever declared an emergency. As the plane proceeded onto the downwind leg, paralleling runway 6 before the final turn to land, the controller clearly suspected that the situation was more serious than the pilots were letting on, and he made sure the B-17 would have a clear path to get on the ground as quickly as possible.

When the controller asked the crew for their progress, Foster started to give a generic reply, but McCauley picked up the mic and talked over him: “We’re getting there,” he grunted.

“…midfield downwind now,” Foster concluded, the rest of his transmission cut off by McCauley.

A video taken by a witness captured the B-17 flying low and slow on the downwind leg. (NTSB)

On board the plane, the situation was becoming far more serious than anyone suspected. With engine four shut down and engine three losing power, the B-17 began to lose speed quite rapidly. As their speed dropped, they began to fall into a terrifying bootstrapping problem. In order to keep their speed up, the pilots needed to accelerate engines one and two to max power, but this would cause a severe thrust asymmetry that needed to be countered using the rudder. However, rudder authority decreases at lower speeds, which meant that as their speed dropped ever lower, McCauley had to decrease thrust on engines one and two to prevent the thrust imbalance from overcoming his rudder inputs and putting the plane into an irrecoverable spin. This caused their speed to drop even more, further exacerbating the situation and creating a deadly negative feedback loop. The only way to get out of the situation was to pitch down into a descent, trading potential energy for kinetic energy, but at a height of just 400 feet above the ground the pilots must have been reluctant to do this.

The path of the plane after striking the approach lights. (NTSB)

By the time the B-17 made its final turn to line up with runway 6, its low speed had caused it to bleed altitude at an alarming rate, and witnesses could easily tell that the plane was coming in too low. The plane barely cleared the treetops at the edge of the airfield before coming down well short of the runway, striking the approach lighting system more than 300 meters back from the threshold. The plane lurched forward another 150 meters before slamming hard onto the grass, quite probably throwing both pilots forward against the dashboard, as they weren’t wearing their shoulder belts. Without anyone in a position to intervene, the thrust imbalance immediately began to turn the plane to the right. Completely out of control, the B-17 careened across a concrete pad before the start of the runway, missed the threshold entirely, slewed off into the grass again, crossed a taxiway, and plowed directly into the airport de-icing facility, where it exploded in flames.

The B-17 and surrounding buildings and vehicles burn shortly after the crash. (Dave Colavecchio)

The impact with the de-icing tanks caused severe injuries to most of those on board, and at least three passengers and possibly the copilot were killed outright. And with flames erupting from the ruptured fuel tanks and smoke pouring into the mangled fuselage, the window of survival for those who remained could be measured in seconds. One of the five passengers in the waist gunner area in the tail quickly managed to open the rear door; another passenger followed him out. A third passenger, having been thrown forward on impact due to a faulty seat belt, regained consciousness and escaped through this same door, which was by then blocked by fire. After bursting through the wall of flames, his life was saved by the passengers who had escaped ahead of him, who managed to tear off his burning clothes.

Toward the front, loadmaster Melton came to his senses in the area behind the cockpit, having survived despite sitting on top of the turret on impact without a seat belt or even a seat. Surrounded by fire, he realized that the only way out was up: thinking quickly, he popped open the plexiglass enclosure around the roof turret and climbed out onto the top of a de-icing tank, followed shortly thereafter by two passengers who had been seated behind the pilots. By this time witnesses were hurrying toward the burning plane to help, including a construction worker who scaled a three-meter-tall barbed wire fence to render assistance. When emergency services arrived a few minutes later — delayed due to the fact that the crew hadn’t requested fire trucks — the plane was already fully consumed in flames, and there was little hope for anyone else still on board.

Drone view of the wreckage. In addition to the plane, two buildings, two de-icing tanks, and three vehicles sustained major damage. (Hartford Courant)

As the six survivors were rushed to hospital, five of them with serious injuries, it became clear that the other seven people on board had not been so lucky. Both pilots were dead, along with two of the five passengers from the waist gunner area and everyone in the radio room — none of the three people seated there lived to tell what happened. Three or four of those who died, including Captain Ernest “Mac” McCauley, survived the impact but perished from burns and smoke inhalation before they could escape the plane. One of these was transported to the hospital with weak signs of life but soon died.

The loss of Nine-O-Nine, Mac McCauley, Mike Foster, and five passengers horrified the tight-knit warbird community in the United States. Although accidents and incidents involving warbirds are fairly common, a crash killing fare-paying passengers is much rarer, and demanded a full investigation. The accident also came at a time when questions were increasingly being asked about the future of the warbird industry in the wake of the crash of a WWII-era Junkers Ju 52 in Switzerland in 2018, in which all 20 people on board were killed.

NTSB investigators examine the number four engine, which was thrown partially into a building. (NTSB)

Although much of the early speculation about the cause of the crash of Nine-O-Nine centered on the plane and its condition, investigators found that while mechanical problems did play a central role, the flight would have been entirely salvageable if not for the actions of the pilots. The issues began with the poorly maintained engines on the right wing, including the problem with the spark plugs on engine three and the problems with the magnetos on engine four. When he couldn’t start the engines, McCauley believed that there must have been moisture in the magnetos, which may have been true, but in any case was only part of the issue. It was also worth noting that the technique of blowing out the magnetos with nitrogen to clear the moisture was not an approved maintenance procedure and had apparently become common practice through word of mouth alone. Furthermore, after blowing out the magnetos, McCauley conducted the engine run-up tests at too low an RPM: the B-17 manual called for a rate of 1,900–2,000 RPM while checking the functioning of the magnetos, while he used 1,700 RPM. The Collings Foundation’s official procedures differed from the manual, but he didn’t use their figure either. By conducting the run-ups at too low an RPM, he missed a chance to detect the fact that both engines three and four were in no condition to operate at higher power settings.

Another view of the wreckage, much of which initially came to rest on top of one of the tanks of de-icing fluid. (ABC News)

Instead, McCauley found this out the hard way while trying to climb away from the airport. Engine four probably began running rough before they even got off the ground, but McCauley must have been convinced that it would somehow sort itself out. Evidently, it didn’t. Realizing that they would need to get back on the ground to give the engine a more thorough check-up, he decided to return to the runway he took off from, clearly expecting the stakes to remain rather low. Indeed, at this point there wasn’t any real cause for concern: losing one engine on the four-engine B-17 happened quite regularly, and there were plenty of stories about B-17s struggling back to base during the war after losing two or even three engines.

However, as soon as McCauley accelerated engine three to compensate for the loss of thrust on engine four, this engine’s own gremlins revealed themselves in the form of continuous detonations and heavy vibrations. And yet, the pilots didn’t seem to appreciate that they were now in an emergency situation: the radio transmissions from the first officer gave no hint that anything was seriously wrong. Although the exact reason for this lack of urgency is not known, some have speculated that McCauley thought the vibrations were coming from engine four and never even realized anything was wrong with engine three.

NTSB investigators at the crash site. (NTSB)

The next critical link in the chain of events was the decision to lower the landing gear very early in the approach. Dropping it so early increased drag right at a time when they needed to extract maximum performance from the plane. With two engines out, the B-17 was still easily capable of making it to the airport, and the crew still had several options. They could have declared an emergency and immediately turned in to land on runway 33, which was closed at the time but could’ve saved them in an emergency situation. This would have prevented the crash, but they flew past it well before realizing they were in an emergency. Now they were at an altitude of around 400 feet and still had several kilometers to go to reach runway 6. To get the plane that far, they needed to keep their rate of descent in check. According to other B-17 pilots, that meant maintaining a speed of at least 193km/h (120mph), which would have required them to pitch down, converting potential energy into kinetic energy. Paradoxically, pitching down would therefore result in less altitude loss than trying to maintain a level attitude, which resulted in constantly decaying airspeed, an ever-increasing angle of attack, and a greater rate of descent. This is what put McCauley into the negative feedback loop where he had to keep reducing power on his remaining engines to prevent a spin, as the ability of the rudder to counter the asymmetric thrust decreased proportionally with their airspeed. Critically, had the pilots not lowered the landing gear until they were lined up with the runway and ready to land, their airspeed would not have decayed to the point where this feedback loop became dangerous. Calculations by the NTSB showed that this change alone would have allowed them to safely reach the runway.

Aerial view of the crash site shortly after the fire was extinguished. (CNN)

In the event, their airspeed kept getting lower and their rate of descent kept increasing until they struck the approach lights 300 meters before the start of the runway. The hard landing may then have turned into a loss of directional control because the pilots weren’t wearing their shoulder harnesses (even though this was required), causing them to be thrown against the control panels in front of them.

This sequence of events showed that the pilots were unaware of the precariousness of their plane’s energy state until very late in the flight, if they realized it at all. Furthermore, the condition of the engines was well outside the manufacturer’s limitations and betrayed a pattern of shoddy maintenance, since all of the issues should have been caught during routine inspections. And a number of other discrepancies throughout the brief flight also raised investigators’ eyebrows, including several mistakes during radio calls, ad-hoc troubleshooting measures, poor cockpit communication, faulty seat belts, and inadequate passenger safety briefings. Collectively, these issues gave off the impression that the Collings Foundation was not exactly running an airtight operation. Further examination of the organization would prove those suspicions correct.

Long-distance view of the wreckage from across the airport. (New York Times)

It turned out that not only was the 75-year-old McCauley the foundation’s chief pilot for the B-17, he was also director of maintenance and was personally responsible for maintaining the plane in addition to flying it. The reason it was in such poor shape was because this was just too much for one man, even with sporadic help from the loadmaster and a couple of other contracted mechanics. The B-17 was 74 years old and wasn’t exactly the epitome of reliability even when new, let alone in 2019, and it needed constant love and attention that a team of one could not provide. A similar dynamic had carried over into the cockpit: interviews revealed that McCauley flew the plane “99% of the time,” hardly ever handing over control to his first officers. Nor did he usually solicit their input, as evidenced by his unilateral shutdown of engine four during the accident flight. The fact that McCauley could be heard on the radio talking over Mike Foster further reinforced the notion that he was doing everything himself, since it’s normally the non-flying pilot’s job to handle the radio calls. Once again, one-man-army Mac McCauley was doing far more than his fair share of the work in a situation that required careful concentration and teamwork.

The left wing and tail were the only parts of the plane to escape the post-crash fire. (NTSB)

The examination of the Collings Foundation turned up a number of other problems as well. Most notable was the state of the foundation’s Safety Management System, or SMS. An SMS is a program designed to collect information about problems with the fleet, identify recurring safety issues, and organize corrective action. Certainly the crash had revealed a number of items that should have grabbed the attention of a properly functioning SMS.

Although the Collings Foundation wasn’t required by law to have an SMS, the FAA had asked for one in 2017 as one of the conditions for its biannual renewal of the organization’s Living History Flight Experience exemption. Thus, in order to keep operating warbirds under the exemption, the Collings Foundation needed to show the FAA that it had a functional SMS that was working proactively. But the SMS really only existed on paper. The program was run by a single part-time volunteer, and most pilots didn’t report problems to him anyway: during the entire period between May 2017 and January 2020, he received just 33 safety reports, of which only two were related to the B-17. This represented only a tiny fraction of the reportable events that a fleet of ten antique warbirds would normally experience in that timeframe. The problem was that the SMS had been set up to comply with the FAA order, not to actually improve safety, and the Collings Foundation had made no effort to make filing SMS reports part of its piloting culture.

One of the B-17’s severed landing gear bogies. (NTSB)

This left investigators wondering why the FAA had allowed the Collings Foundation to keep operating this woefully inadequate SMS, despite it being the basis of its approval of the foundation’s exemption. Here the NTSB uncovered another bombshell. For matters related to the exemption and other regulations, the Collings Foundation communicated with the FAA via a point of contact, who turned out to be an inspector based at the FAA’s regional offices in Orlando, Florida. But this inspector died in a plane crash in late 2016 or early 2017 and was never replaced. The fact that he had been overseeing the Collings Foundation somehow slipped through the cracks in the busy office without anyone noticing. When the Collings Foundation asked who was supposed to take their regulatory questions, another inspector told them to use the office’s general email address, which they did. But every email they sent to this address went unanswered, so eventually the Collings Foundation simply stopped attempting to communicate with the FAA. As a result, their proposal for a safety management system was never reviewed by the agency — and yet, in February 2018, the FAA renewed the Collings Foundation’s Living History Flight Experience exemption on the basis of that very same SMS which no FAA inspector had seen!

Wreckage from the airplane came to rest up against two warehouses at the de-icing station. (NTSB)

It was now clear that the ad-hoc culture at the Collings Foundation had been allowed to develop due to a complete lack of FAA oversight, as no one was assigned to oversee them. There is probably an interesting story to be told about the sequence of events within the FAA’s Orlando offices that caused the agency to literally forget about one of the operators under its purview, and then later rubber-stamp their permission to fly antique warplanes without anyone apparently noticing the problem. But that story, although there is surely someone who can tell it, has not yet been told.

As a result of the NTSB’s findings, the FAA revoked the Collings Foundation’s Living History Flight Experience exemption in March 2020, and later denied an appeal by the foundation to get it back. But this came too late to save the lives of seven passengers and crew aboard Nine-O-Nine, whose deaths stand as yet another monument to the FAA’s purely reactive approach to safety.

The B-17 Nine-O-Nine takes to the skies sometime before the crash. (CNN)

In light of the B-17 crash and numerous other accidents, the NTSB issued several recommendations and a detailed report calling on the FAA to require safety management systems at all operators carrying fare-paying passengers under Part 91 of the federal aviation regulations, including those conducting living history flights. It also called on the FAA to enact rigorous oversight of these programs once established. At the time of this writing, the reports into the crash and into the safety of all Part 91 revenue operations are only a few weeks old, and it remains to be seen how and whether the FAA will take action to address the NTSB’s concerns.

The long-term effects of the accident on the warbird industry are also unclear. After the accident in Switzerland in 2018, that country moved to restrict the ability of operators to carry fare-paying passengers on vintage airplanes, but so far there haven’t been any signs that the USA is preparing to take similar measures. Nevertheless, it should be clear to operators that they cannot afford a repeat of the loss of the Nine-O-Nine. The best way to proactively guard against such an accident would be to recognize a hard truth: that in the 21st century, it is irresponsible to operate, maintain, or fly an antique warbird like it’s still 1945. The way things were done when these planes were new bears no resemblance to how things are done today, and while it may be tempting to believe that what was good enough for the Greatest Generation is good enough for us too, this just isn’t true. In 2021 we are capable of operating planes like the Flying Fortress at a much higher level of safety than could be achieved 75 years ago. The question is, will we?

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Analyzer of plane crashes and author of upcoming book (soon™). Contact me via @Admiral_Cloudberg on Reddit or by email at kylanddempsey@gmail.com.