Strength in Numbers: The crash of National Airlines flight 102

Note: this accident was previously featured in episode 29 of the plane crash series on March 24th, 2018, prior to the series’ arrival on Medium. This article is written without reference to and supersedes the original.

The last moments of National Airlines flight 102 were captured by a dashboard camera. (CNN)

On the 29th of April 2013, a Boeing 747 cargo plane evacuating military equipment from Bagram Airfield in Afghanistan abruptly pitched up, stalled, and plunged into the ground, triggering an earth-shaking explosion seen, felt, and heard by thousands of people. By the time emergency crews arrived, all that remained of the 747 was a smoking field of wreckage, through which were scattered the twisted remains of the five massive armored vehicles that made up its cargo. None of the seven people on board had survived.

Before long, a video of the crash spread around the world, generating intense interest in the dramatic accident and the complex sequence of events which had led to it. As investigators worked in difficult conditions to solve the case, suspicion fell on the cargo itself. Somehow, an armored vehicle had come loose, rolled back, and smashed its way through critical flight control systems, leaving the pilots as passengers aboard their own plane as it plunged to its doom. How they figured it out was a story all of its own. But so was the deeper cause, which turned out to be a fundamental misunderstanding of physics, math, and geometry, enabled by a dangerously misleading manual and a lack of technical education for those whose job was to read it. These findings, and the new rules which they precipitated, would change the way American cargo airlines train their staff and load their freight — but the reforms would also leave one glaring vulnerability that could yet kill again.

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The seal of the United States Transportation Command. (US Department of Defense)

America is famous for its ability to project military power into even the remotest corners of the world, but this capacity is built upon a foundation which gets little press: the United States Transportation Command, a vast network of both military and civilian assets which are coordinated at a high level in order to move weapons, troops, and supplies to the location of any major military operation. Perhaps the most complex mission in the department’s history was to supply the US war in Afghanistan, a 20-year conflict fought in a landlocked country on the other side of the world surrounded by America’s geopolitical adversaries. But the differences between the system which brought weapons to Afghanistan and the system which brings you your Amazon packages may be fewer than you think: in fact, much of the logistical capacity of the Transportation Command belongs to commercial cargo airlines which carry military supplies and equipment under contracts doled out by the Department of Defense.

N949CA, the aircraft involved in the accident. (Luis David Sanchez)

By 2013, a surge in US troop levels in Afghanistan, initiated in 2010, was drawing back down, as were the parallel operations by several of America’s allies, including the United Kingdom. Of course, almost as important as the task of getting the military equipment to the war zone was the task of getting it back again, and it is during this phase that we pick up the story of a particular blue-and-silver Boeing 747 and its ill-fated crew.

One of the companies contracted to haul equipment out of Afghanistan on behalf of the US Transportation Command was National Airlines, a commercial cargo carrier which specialized almost exclusively in DoD contracts. The airline’s fleet of converted Boeing 747 freighters was a frequent sight at major bases in Afghanistan, both American and otherwise, as several other countries in the coalition also employed their services. One of these planes, registered as N949CA and nicknamed “Lori,” arrived empty at Camp Bastion, the only remaining British base in Afghanistan, on the 29th of April, 2013, after a flight from Châteauroux, France.

Left: an Oshkosh M-ATV (Wikimedia user PEOSoldier); Right: a Cougar (public domain image).

National Airlines had been informed of the mission just three days earlier by its load planning contractor, an entity called National Air Cargo, or NAC, which was owned by the same parent company. The relationship between the two companies would later be described as “you call, we haul,” and the airline was not in the habit of asking too many tough questions. So when an NAC representative called National Airlines’ chief loadmaster on April 26th, informing him that they planned to load N949CA with five large armored vehicles at Camp Bastion in three days’ time, go-ahead was given after little more than a quick check of the cargo’s expected weight.

The cargo consisted of two different types of mine-resistant ambush-protected vehicles, or MRAPs. These hulking conveyances are coated in heavy armor designed to protect their occupants from landmines and improvised explosive devices, and even the smallest among them dwarf the now-obsolete Humvees which once shepherded US troops around war zones in the Middle East. Two of the MRAPs scheduled for removal from Camp Bastion were M-ATVs (pronounced “mat-vees”), designed for travel on any terrain, and weighed twelve tons apiece. The remaining three were even larger Cougars, each of which clocked in at a whopping eighteen tons. The vehicles, which stood nearly 3.3 meters in height, were too large to fit onto the 747’s built-in cargo loading and securement system, so special measures would have to be taken to get them safely aboard.

A M-ATV being secured aboard a cargo plane at an unspecified date and time. (Unknown author)

At Camp Bastion, NAC personnel tied each MRAP to a double-stacked pallet using chains, and placed shoring under the wheels in order to more evenly distribute the load and avoid exceeding the structural capacity of the cargo bay floor.

Normal cargo which could be placed in standard containers could be loaded onto the 747 using its Telair cargo loading system, which featured tracks in the main deck floor designed to fit the containers, as well as built-in locks to hold them in place once properly positioned. The MRAPs, on the other hand, would have to be secured using tie-down straps by the National Airlines loadmaster, who was arriving with the airplane.

N949CA reached Camp Bastion on the morning of the 29th with seven crewmembers on board. For the next leg of the journey, which would take them to Dubai, the flight crew was to consist of 34-year-old Captain Brad Hasler and 33-year-old First Officer Jamie Lee Brokaw, who were joined by loadmaster Michael Sheets, two mechanics, and two relief pilots. None of them had ever flown MRAPs before, although this was far from their first time in Afghanistan.

Upon arrival, the MRAPs were loaded into the cargo hold by NAC personnel, with the three Cougars in the middle and the M-ATVs on the ends. Meanwhile, loadmaster Michael Sheets calculated that they would need 24 tie-down straps for each M-ATV and 26 for each Cougar. He based his calculations off of the National Airlines cargo operations manual, which stated that the number of straps required to secure the cargo against in-flight excursions of up to 1.5 G laterally and 2.2 G vertically could be reached by dividing the weight of the cargo by 3,750 pounds (1,700kg), the strap load limit. The tie-down straps were actually rated to carry up to 5,000 pounds (2,270kg) each, but National Airlines employed a 75% safety factor for good measure. Based on these procedures, Sheets determined that each M-ATV could be secured by 12 straps in the front and 12 straps in the back, with each set of 12 reacting against 45,000 pounds (20,400kg) of force in the fore and aft directions respectively, while all 24 straps would react against up to 90,000 pounds (40,800kg) of force in a vertical direction.

Readers who have studied physics might see the problem already. In fact, there were three main issues with the procedure which was used to determine the method of restraining the MRAPs. For one, the calculations did not take into account the strength of the strap attachment points, which was often lower than the 3,750-pound allowable load limit of the straps. Second, and more importantly, the actual load capacity of a tie-down strap depends on its angle relative to the force which it is reacting against, and thus the capacities of straps at different angles are not the same, and straps which react against a lateral force cannot be counted as reacting against a vertical force, and vice versa.

Simplified diagram of why strap angle is important. (Own work)

Consider, for example, a 5,000-pound load which may roll forward or backward. Now imagine that a single strap, rated to hold 5,000 pounds, is attached to the front of the load. If this strap is then connected to an attachment point such that it is parallel to the floor (i.e., its angle relative to the floor is zero degrees, as shown in the above diagram), then it will be able to prevent the load from rolling backward without any trouble, as it is reacting directly against the opposite force with its full tensile strength. In fact it would be able to hold back considerably more than 5,000 pounds, because the load ratings used for the 5,000-pound tie-down straps assumed that the strap was angled 30 degrees relative to the floor.

Now consider the same strap attached to the same cargo, but rising directly upward from the floor at a 90-degree angle. In this case, if the cargo were to roll backward, the amount of force against which this strap could react is actually zero. Cargo secured by a strap angled vertically will roll back without any initial resistance, because the strap is only reacting against forces in a vertical direction. As such, if the cargo were to suddenly move upward, this strap would react with its full 5,000-pound capacity, but it will not counter a lateral motion at all. Therefore, to summarize another way, a strap lying flat will react against a lateral force; a strap stretching vertically will react against a vertical force; and a strap at 45 degrees will react at partial capacity against both.

Tie-down straps are placed at many overlapping angles to react against forces in multiple directions. (NTSB)

This meant that the loadmaster’s calculation of how many straps he needed to secure a M-ATV was heavily dependent on the angle at which the straps were installed. If he installed all the straps laterally, they would be sufficient to prevent the vehicle from moving forward or backward, but would be useless in preventing the load from slamming into the ceiling were the plane to suddenly drop. Conversely, if he attached all the straps vertically, the load would never rise off the floor, but would easily roll away as soon as the plane tilted backwards on takeoff. And if he attached them all at 45 degrees, the load would not be sufficiently restrained in either direction, because he had counted each strap’s full capacity toward both lateral and vertical motion, when in fact a strap’s ability to react in one direction is inversely proportional to its ability to react in the other. As such, the practice of simply dividing the total weight by the capacity of the straps to determine the required number of tie-downs was useless at best and dangerously misleading at worst.

A Cougar is loaded onto the N949CA at Camp Bastion on the day of the accident. (NTSB)

The exact configuration of the tie-down straps used to secure the MRAPs on board N949CA is not known, but it was mathematically impossible to reach the required level of restraint using only 24 straps for each M-ATV and 26 for each Cougar. Despite this fundamental deficiency, however, the cargo was declared secure, and the flight crew prepared to depart Camp Bastion sometime after noon.

The next leg of the flight was supposed to take them to Dubai, but that plan had to be significantly modified due to political roadblocks. American military flights into and out of Afghanistan are often forced to take indirect routes in order to avoid airspace belonging to unfriendly nations, in particular Iran, which lies directly between Afghanistan and Dubai. The original plan was for N949CA, operating flight 102, to head southeast across Pakistan before doubling back, but shortly before the flight the airline learned that Pakistan had not granted permission to use its airspace. At Camp Bastion, which was in an advanced state of disassembly, it was not possible to uplift enough fuel to fly around Pakistan too, so an additional stop was added at Bagram Airfield, a massive US base in northern Afghanistan, in order to take on more fuel before the trip to Dubai.

The possible route of National Airlines flight 102. Dashed portion is presumed; flight plan data was not available. (Google + own work)

Despite the improper cargo loading, flight 102 departed Camp Bastion without incident and landed in Bagram at 13:53, after approximately 100 minutes in the air. Ground crews then set about refueling the plane, while the pilots chatted in the cockpit and the loadmaster inspected the cargo. What he found was disturbing: a strap had broken, and one of the MRAPs had moved. The pilots’ conversations related to this discovery were captured on the cockpit voice recorder, beginning at 14:27.

“There’s your trouble, Brad,” First Officer Brokaw could be heard saying, presumably displaying the broken strap.

“What is it?” Captain Hasler asked. Upon seeing the strap, he exclaimed, “What the hell was that from?”

“One of those fucking straps is busted,” Brokaw replied.

“No, no, I know that,” Hasler said. “No, I know, but — “

“Give you one guess what was right there,” said Brokaw.

“What was right where?”

“Right here,” Brokaw said, perhaps pointing to the broken part of the strap.

“A knot?”

“Uh huh.”

“So you going putting more straps on shit?” Hasler said.

“Well it just shifted barely,” said Brokaw.

“There was a bunch of them first… that first truck,” chimed in the relief Captain, Jeremy Lipka.

“Did it move?” Hasler asked. “Shit moved?”

“Yes. Just tightened up on the straps,” said Brokaw.

“Like, tightened those straps up, uh, quite a bit on the first one,” said Lipka.

“You know how that… well, they had a bunch like this, to keep them from moving backwards, a bunch like this [to keep them from] moving forward?” Brokaw said. “All the ones that were keeping ’em from moving backwards were all fucking loose.”

“What the hell do you think’s gonna happen when you fucking slam it on the runway and slam on the fucking brakes and don’t use reverse!” Lipka joked.

Captain Hasler laughed.

“There ain’t nothing you could have done about that,” said Brokaw.

“I’m putting it on the motherfucking board, I’m getting off this plane, I’m scared,” Lipka said, his voice dripping with sarcasm.

“I hope instead of, rather than just replacing that strap I hope he’s beefing the straps up more,” Hasler said.

“Just in that one spot.”

“Yeah.”

“All the rest of them are fine,” someone said.

“He’s cinching them all down,” Brokaw added.

Some of the crewmembers of flight 102. (CBS News and the Brokaw and Sheets families)

Fifteen minutes of non-pertinent conversations ensued before loadmaster Michael Sheets entered the cockpit and the topic returned to the cargo.

“What’s up, dude?” said Hasler.

“Did you throw the other strap away?” Brokaw asked.

“What did you — did you put a couple more on? How far did it move, a couple inches?” said Hasler.

“Yeah, they just moved a couple inches, cause you know, it’s nylon ya know, so,” said Sheets. He seemed to believe that the inherent stretchiness of the nylon tie-down straps was the reason why one of the MRAPs had moved during the flight.

“You throw some numbers in here?” Brokaw asked.

“That’s fucking scary,” said Hasler. “Without a lock for those big heavy things — man, I don’t like that. I saw that, I was like shit, I never heard of such a thing.”

“I’d be kinda interested to… wish I could put a camera down there and watch it, see what they do,” someone said.

“You’d probably shit yourself,” said Brokaw.

“Those things are so fucking heavy you’d think though they probably wouldn’t hardly move no matter what,” said Hasler.

“They always move,” said Sheets. “Everything moves. If it’s not strapped — ”

“No, no, I — “

“ — It’ll roll on them things, brrrrrrr,” Sheets concluded.

Sheets’ impression of a motor elicited laughter. But the discussion ended there, and the conversation never seriously touched on the cargo again.

By 15:20, flight 102 was on the roll, taxiing to the runway for takeoff. In the cockpit, Captain Hasler and First Officer Brokaw prepared the plane for departure while chatting with relief Captain Lipka.

“Is Rinku there?” Lipka asked, referring to the relief First Officer, Rinku Shumman. “I haven’t seen him. I hope he’s in the bunk.”

“Yeah, that’d be better if he was,” said Brokaw.

“He didn’t get off,” said Hasler.

“No.”

“Yeah, he’s in there,” said Lipka.

“Shit, do a nose over and put him through the ceiling,” Hasler joked.

“Yeah uh. Him and those, uh, those MRAPs,” said Brokaw, betraying just a hint of apprehension.

The conversation soon turned to duty times. All the crewmembers had been on duty for many hours at this point, including the loadmaster, and they were all looking forward to resting in Dubai.

“That’s right, we earned it as far as I’m concerned, man,” said Hasler. “I don’t think — min[imum] rest, I’d be dead tomorrow, man.”

“Yeah. I think I would have to agree with that sentiment,” said Brokaw.

“I’m dead right now,” Lipka joked.

Traffic was heavy, and they spent several minutes waiting in line, but at 15:25, flight 102 finally received takeoff clearance. The pilots pushed the thrust levers forward, and the 747 began to roll down the runway, all parameters appearing normal as it gathered speed. They reached decision speed, then rotation speed, and Hasler called out “Rotate.”

Six seconds later, he noted, “Positive climb.”

“Gear up,” said Brokaw.

“Keep on that [unintelligible],” Hasler warned. And then both flight recorders simultaneously went dead.

This animation of the MRAP rolling backward appeared in Mayday season 16 episode 10: “Afghan Nightmare.”

In the main deck cargo hold, the rearmost MRAP suddenly broke loose as the plane rotated for liftoff. The 12-ton M-ATV slid backward, crashing into the rack containing the flight recorders, before plowing straight into the aft pressure bulkhead, the hemispherical wall separating the pressurized cargo deck from the unpressurized empennage behind it. Severing numerous hydraulic lines in the process, the M-ATV then burst through the bulkhead and slammed into the jackscrew which controls the horizontal stabilizer.

The impact damaged hydraulic systems 1 and 2, and possibly system 3, and severed the jackscrew from its drive motor, pushing the entire stabilizer around five units toward the nose up position. With the stabilizer now at 9 units nose up instead of four units as the crew had intended, the plane began to pitch up alarmingly, almost certainly prompting the pilots to apply full nose down pressure using the elevators. But with hydraulic fluid from two or three of the plane’s four systems unable to reach the tail due to the breach in the aft pressure bulkhead, the elevators had lost between 50 and 75 percent of their pitch authority. No matter how hard they pushed, the plane kept climbing ever more steeply, driven inexorably upward by the power of the horizontal stabilizer. Witnesses heard the pilots accelerate the engines to maximum power, and they probably tried to push the stabilizer toward nose down using the electric switches, but with the drive motor no longer connected to the jackscrew, they were powerless to move it. Whether the crew realized it or not, flight 102 was doomed.

The final seconds of flight 102 were captured on this dashcam video. (CBS News)

As dozens of people looked on in horror, the huge plane rose to a height of perhaps 1,000 feet above the ground, reaching an extreme nose up attitude that appeared almost vertical. For a moment, it seemed to hang stationary in the air, its engines screaming in a futile effort to keep it aloft, before it abruptly spiraled inward around its right wing and began to plunge toward the ground. Banked nearly 90 degrees to the right and falling fast, there was no time to attempt a recovery. The pilots managed to level the wings, but before they could even think of pulling out of the dive, the fully loaded 747 plowed nose-first into the ground, disappearing into a tremendous wall of flame. The fire billowed outward, then upward, wreathed in pitch-black smoke, until it towered like a mushroom cloud above Bagram Airfield, engulfing the shattered wreckage of the airplane and its unfortunate crew.

Although the full video has not been released, this still was taken from a security camera on the base. (NTSB)

Although thousands of people either saw the crash, heard the explosion, or saw the smoke, there was nothing any of them could do to help. Rescuers hurried to the scene and firefighters tackled the blaze within minutes, but all seven crewmembers had died instantly on impact. Little remained of the plane, save for the tail section and the mangled carcass of a M-ATV; most of the rest of the aircraft had been reduced to charred rubble, strewn across a field and a road and into several temporary buildings.

Shortly after the crash, a video appeared on the internet, uploaded by a US military contractor, which captured the final moments of flight 102 in shocking detail from inside a car traveling on the airport perimeter road. The video soon racked up millions of views and was replayed by news stations around the world, extending the impact of the crash far beyond the dusty outskirts of Bagram Airfield. Under intense public scrutiny, National Airlines was soon forced to go on the defensive, and within hours New Zealand paused the withdrawal of its equipment from Afghanistan in order to arrange transport with other carriers. Multiple governments were now demanding to know: could they count on US cargo airlines to get their equipment out of the country intact?

An aerial view of the crash site. (Unknown author)

Under international law, responsibility for the investigation lay with Afghanistan’s Ministry of Transportation, which opened an investigation that same day. Investigators from the US National Transportation Safety Board also traveled to Afghanistan to assist. Although the NTSB is widely credited with leading the inquiry from the start, Afghanistan was at least nominally in charge throughout most of the investigative process, until the investigation was officially delegated to the NTSB in October 2014, more than a year after the crash.

Although the Taliban opportunistically claimed responsibility for bringing down the plane, US military experts quickly ruled out any kind of terrorist attack due to lack of evidence, and a problem with the aircraft’s cargo soon became the leading theory about the cause of the accident. However, the black boxes, which otherwise would have provided important data about the aircraft’s performance, cut out just three seconds after liftoff, forcing investigators to go back to basics, examining the wreckage itself for clues.

Impact point of the M-ATV tire on the aft pressure bulkhead. (NTSB)

The number of clues hidden in the wreckage proved to be substantial. For one, several pieces of the plane were found on the runway, including a piece of fuselage skin, a section of tubing from hydraulic system 2, and part of the antenna assembly from a M-ATV. At the crash site itself, the aft pressure bulkhead was found shattered into several pieces, but when reassembled they showed a clear circular impact mark which lined up perfectly with the location of the spare tire mounted on the back of the rearmost M-ATV. This mark could only have been made by the M-ATV rolling backward on takeoff, because the impact of the subsequent crash was largely vertical and would have sent the M-ATV into the ceiling, not into the bulkhead. The M-ATV’s antenna assembly also showed traces of orange paint consistent with that used on the flight data recorder and cockpit voice recorder, which were mounted just in front of the bulkhead at a point which corresponded to the height of the M-ATV’s antenna. This finding made it immediately obvious why the flight recorders had failed on takeoff.

From there, the presence of hydraulic tubing on the runway showed that hydraulic lines inside the aft pressure bulkhead must have been damaged as the M-ATV rolled backward. Hydraulic system 2 was known to have failed based on examination of the runway debris, while video footage of the crash from multiple angles helped fill in the rest. In various photos and videos of the plane in flight, some of its landing gear was observed to be extended while some was retracted — a configuration that could only have been the result of a partial hydraulic failure. The left wing landing gear had retracted successfully, indicating that system 4 was working, while the body gear and nose gear were still extended, indicating that systems 1 and 2 were not. None of the videos showed the underside of the right wing, so the integrity of system 3 could not be established.

On top of all this evidence, the jackscrew which controls the horizontal stabilizer also provided telltale clues. The massive screw had been sheared off in a rearward direction a few centimeters above the drive motor, a failure mode inconsistent with the primarily vertical forces involved in the final impact. The position of the jackscrew was such that it would have been struck by the M-ATV’s spare tire after passing through the aft pressure bulkhead, strongly indicating that this was what caused it to break.

How the M-ATV punched through the aft pressure bulkhead (APB) and impacted the jackscrew. (NTSB)

The NTSB carried out a number of simulations in order to determine which combination of failures, chosen based on this wreckage analysis, resulted in a flight path which most closely resembled that captured on the dashcam video. They found that even with all five MRAPs shifted backward, causing the center of gravity to move out of limits, but without any damage to systems, control could be recovered within five seconds by applying full nose down elevator. Control could also be quickly regained with three MRAPs shifted back and three failed hydraulic systems, or four MRAPs shifted back and two failed hydraulic systems, because the 747’s four separate elevators were each powered by a separate hydraulic system. Control would however be lost if two or three hydraulic systems failed and all five MRAPs rolled backward, because the remaining elevator control would be insufficient to overcome the shift in center of gravity.

However, evidence suggested that it was more likely that only one MRAP shifted backward during flight 102’s ill-fated takeoff. Only one MRAP had moved during the previous flight; furthermore, it would probably have taken more than three seconds after liftoff for a chain reaction dislodging all five MRAPs to escalate to the point that the flight recorders were knocked offline. Assuming only the rearmost MRAP moved during the flight, then the only way to produce the observed flight path was to assume a failure of the jackscrew resulting in a 5-unit increase in the nose up stabilizer position, consistent with the displacement observed on the jackscrew wreckage, in addition to the failures of at least two hydraulic systems. In this case control would be lost if the stabilizer jammed in a nose up position, because the remaining elevator authority would be insufficient to overcome it. Control also would almost certainly have been lost if the stabilizer became free-floating, because aerodynamic forces associated with nose down elevator inputs during the attempted recovery would drive a free-floating stabilizer farther into the nose-up position. The NTSB therefore concluded that the damage to the jackscrew, in combination with damage to at least two hydraulic systems, resulted in an uncontrollable climb, stall, and descent from which recovery was impossible.

Damage to the jackscrew after the crash vs. its normal mounting position. Both the screw and its drive motor were rotated upward into the structural beam on impact, but the rearward separation of the screw from the motor must have occurred before that. (NTSB)

At the same time, NTSB and Afghan investigators interviewed NAC cargo loading personnel, consulted other National Airlines loadmasters, and reviewed the National Airlines cargo operations manual in order to understand why the rearmost M-ATV came loose during takeoff from Bagram. What they found was a lack of knowledge of proper cargo restraint procedures which was staggering in its totality.

Because the MRAPs would not fit in standard cargo containers, they were considered “special cargo” which had to be tied down according to non-specific “special cargo” instructions in the cargo operations manual. The basic issue, as explained earlier, was that this manual presented the determination of tie-down requirements as a simple division problem when it was not. It did not explain that the load capacity of a tie-down strap depends on its angle, did not explain that straps cannot react at full capacity in multiple directions at once, and neglected to mention that some strap attachment points may not be as strong as the straps themselves. In fact, if one followed the procedure in the manual without knowing about these items beforehand, it was trivial to arrive at a figure of 24 straps for each M-ATV and 26 for each Cougar, the exact numbers given to the NTSB by the NAC cargo loaders at Camp Bastion after the accident. The loadmaster had produced these numbers in the belief that each strap could react against 3,750 pounds of force in both the horizontal and vertical directions, which was untrue, and without considering that their rated load only applied if the angle of the strap relative to the direction of movement of the cargo was 30 degrees or less. While the exact angles of the straps as actually installed are not known, it is certain that some were not pulling their weight. The fact that a strap broke during the flight from Camp Bastion to Bagram Airfield proved that the few straps which were actually restraining the cargo were being overstressed in their efforts to make up for the other straps which were doing nothing at all.

The M-ATV which caused the accident was still recognizable even after the massive impact. The fact that its rear end was completely flattened was evidence that it was positioned beneath the tail on impact, and the vertical stabilizer came down and crushed it. (NTSB)

During the stopover in Bagram, the loadmaster informed the pilots that a strap had broken and an MRAP moved several inches. However, evidence on the cockpit voice recording suggests that the pilots believed the strap itself was faulty, perhaps because it had a knot in it. Furthermore, the loadmaster seemed unperturbed by the movement of the MRAP, noting that “everything moves.” Investigators noted that while the pilots seemed uncomfortable with the cargo, they were not trained on cargo loading techniques and it was not common practice for them to inspect the manner in which the cargo was restrained; as such, they would have had no reason to distrust the loadmaster’s calculations and no means to judge whether he had restrained the cargo correctly. Other National Airlines pilots confirmed that they were expected to trust their loadmasters unconditionally when it came to restraining the cargo. Although their jokes about the situation now appear tragically prescient, the pilots would have had no way of knowing how much danger they were truly in. Consequently, the NTSB determined that the pilots’ actions did not contribute to the crash, nor could they have reasonably averted it.

Diagram of the crash site and debris found near the runway. (NTSB)

The trickier question was whether the loadmaster should have known better. Obviously the manual was faulty, but could his training have given him the knowledge he needed to angle the straps correctly? The answer, as it turned out, was no.

In the United States at that time, regulations did not define the position of “loadmaster” and personnel responsible for loading and securing cargo were not required to be certificated. The Federal Aviation Administration did not mandate what loadmasters should be taught during training, and airlines could hire anyone off the street, subject them to a company-designed training course, and release them for work without the FAA being involved at any step of the process. In the case of National Airlines, the training program was created by the airline’s Chief Loadmaster without input from the training or safety departments, based on the cargo operations manual, which he also wrote. The NTSB called this training “highly questionable” because it was based on the same cargo operations manual already established to be dangerously misleading.

The Chief Loadmaster told the NTSB that he assembled the cargo operations manual by borrowing bits and pieces of other manuals, including the Boeing cargo manual, the manual for the Telair cargo loading system, and the cargo operations manuals of other airlines. Somehow during this process he thought it was a good idea to turn the cargo restraint calculations into a basic division problem. Why he failed to understand that this would not work is a vexing question which lacks a clear answer. The consequence, however, was that every future loadmaster at National Airlines was trained to use incorrect procedures that would inevitably result in cargo coming loose at some point down the road. The only reason it took as long as it did is because most cargo could be locked in place using the built-in Telair system without resorting to tie-down straps.

How a single M-ATV should have been secured if Boeing guidelines for tall, rigid cargo were followed. (NTSB)

The NTSB also noted that, according to the Boeing and Telair cargo loading manuals, the MRAPs would have been considered “tall, rigid cargo,” requiring special restraint mechanisms to prevent it from slamming into the underside of the upper deck passenger compartment during a 9-G deceleration, which the cabin is required to withstand during a crash landing. Tall, rigid cargo must either be restrained such that it will not move during a 9-G deceleration, or must be positioned behind loose, frangible cargo sufficient to stop it before it impacts the upper deck passenger compartment. According to Boeing’s interpretation of these requirements, it was only possible to carry one M-ATV at a time due to the number of tie-down points or the amount of frangible cargo required to shield the cabin under such a deceleration. The much heavier Cougars could not be carried aboard the plane at all. Telair, the manufacturer of the cargo loading system, interpreted the rules slightly differently and concluded that neither M-ATVs nor Cougars could be carried. In any case, however, the requirements for tall, rigid cargo were omitted from the National Airlines cargo loading manual, so the loadmaster could not have noticed that the 747 could not legally carry five MRAPs.

Flight 102’s horizontal stabilizer is recovered after the crash. (NTSB)

In summary, therefore, all cargo loading procedures and knowledge at National Airlines stemmed from an incomplete and misleading manual and training course developed by one man who was not legally required to know what he was doing. Because of this failure at the highest levels of the airline and the regulatory system itself, loadmaster Michael Sheets almost certainly could not have realized that much of what he thought he knew about the use of tie-down straps was wrong. As such, it was unfair to blame him for the accident, and the NTSB concluded that it was the manual itself, rather than Sheets’ faithful execution of its contents, which caused the crash.

Smoke rises over Bagram after the crash. (Albert Ramirez)

The NTSB also criticized a number of organizational issues at National Airlines, from its lack of oversight of the activities of its sister company National Air Cargo, to the absence of a cargo operations manual available to the NAC personnel at Camp Bastion, to its failure to conduct a risk analysis before accepting transportation of large military vehicles. At the same time, the NTSB criticized the FAA for not catching on to the problem sooner. This was caused in part due to a lack of clarity about which FAA inspector was responsible for ensuring that cargo loading was carried out correctly, and a lack of guidance and training for inspectors regarding what correct cargo loading was supposed to look like in the first place.

Furthermore, the FAA inspectors assigned to National Airlines were not able to monitor the company’s operations in Afghanistan due to US State Department restrictions on travel to the country by US government employees. At that time, National Airlines was not operating anywhere other than Afghanistan, prompting the NTSB to raise concerns about whether existing rules were creating a situation in which an airline was essentially not being monitored by the FAA. In practice, the FAA inspected National Airlines’ operations by having the company fly a 747 to the US and hop around between different cities with no cargo on board, which did not allow the inspectors to discover the airline’s dangerous cargo loading practices. The FAA did learn in early 2013 that National Airlines was hauling large military vehicles, but the Principal Operations Inspector assigned to the airline declined to conduct a risk assessment, because in his opinion “the manual seemed sufficient,” and “if they were following their manual, there should not be an issue.” Obviously in hindsight this turned out to be incorrect.

Overview of the crash site, with locations of aft pressure bulkhead fragments labeled. (NTSB)

As a result of these findings, numerous steps were taken to try to improve the safety of cargo airlines in the United States. The US military, for its part, stopped using civilian contractors to transport heavy military vehicles. National Airlines also rewrote its cargo operations manual and training program, created a team to evaluate loads and plan their securement, and began training pilots to recognize incorrect cargo loading. But substantive changes would have to come from the FAA.

Initially, the FAA reacted by issuing an operations bulletin explaining the mistakes made by the National Airlines cargo operations manual, as well as urging airlines to use FAA-approved materials to develop clear procedures for restraining “miscellaneous” cargo and to use “qualified loadmasters.” The NTSB noted that this bulletin conflicted with a previous FAA advisory circular, which was still in force, stating that airlines could develop their own independent procedures for restraining cargo types not mentioned under FAA regulations. They also noted that there was no such thing as a qualified loadmaster per the FAA’s own rules. Instead, the NTSB urged the FAA to put in place a certification requirement for loadmasters, something it had previously recommended after the similar crash of Fine Air flight 101 in 1997. The military had recognized this responsibility long ago, as military loadmasters are considered full crewmembers who must be certificated, and in the NTSB’s opinion it was unconscionable that in 2014 there was still no such requirement in the civilian sector.

Pieces of flight 102’s tail section lie in the desert after the crash. (NTSB)

The FAA did not immediately respond to this recommendation, but it did set up a permanent “cargo focus team” whose mission was to provide technical support to FAA inspectors who oversee air cargo operations. The cargo focus team subsequently initiated an in-depth analysis of the cargo operations manuals of every US cargo airline, fixing any flaws that were discovered in the process. The team ended up putting out a large amount of guidance for inspectors to use when evaluating an airline’s cargo loading procedures.

But while the FAA did study the possibility of certifying loadmasters, it ultimately declined to establish a certification requirement, opting instead to implement a long list of “risk mitigations” intended to ensure that cargo loading was conducted in a safe manner regardless of whether loadmasters were certificated. The NTSB strongly protested this decision, but in February 2022, it was forced to give up its efforts, just as it had after the 1997 Fine Air crash. In a bitter reply to the FAA’s final letter on the subject, the NTSB wrote: “Without creating a certification for loadmasters, we are unsure how you would ensure that air carriers’ programs include the procedures [and] training… consistent with other safety-sensitive, certificated positions.” Their point is a valid one: as long as there remains no FAA-enforced qualification standard for loadmasters, there is no direct assurance that loadmasters will possess the knowledge needed to load cargo safely.

One last look at the accident sequence. (CNN)

Although cargo operations in the United States were made safer because of the reforms stemming from the crash of flight 102, the continued lack of a legal standard of qualification for loadmasters is troubling. For the moment a repeat accident is unlikely, but in the long term, the informal conditions which precipitated the accident may return unless the FAA takes an active role in certifying each and every loadmaster as it would a pilot, mechanic, or dispatcher. The FAA’s decision to do everything but this most critical step suggests that the agency fears the costs associated with creating certification infrastructure for loadmasters. Unfortunately, it will probably require another cargo-related accident for the FAA to work up enough courage to ask Congress for the money.

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Analyzer of plane crashes. Contact me via @Admiral_Cloudberg on Reddit, @KyraCloudy on Twitter, or by email at kyracloudy97@gmail.com.

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Admiral Cloudberg

Analyzer of plane crashes. Contact me via @Admiral_Cloudberg on Reddit, @KyraCloudy on Twitter, or by email at kyracloudy97@gmail.com.