Aircraft Accidents and a Bad Act

Johnny Carson was the King of Late Night talk shows; he earned the title by keeping politics in their place and recognizing talent. Johnny personally started comedian careers, because his producers cultivated the up-and-coming talent, preparing them for The Tonight Show stage. But, every once in a while, one bad act got through, something that should, instead, have graced the recording studio for The Gong Show, and the audience knew a producer would have a bad day the next day. Despite this, Johnny Carson was an entertainer; his impact on America was to provide a good show and some laughs. His mistakes and missteps never hurt anyone, even unintentionally.

Malaysia Airlines flight MH370 is back in the headlines again. As per Emerging Technology from the ArXiv in a Technology Review article, new data analysis could help locate the missing airliner. The article states that, “a new mathematical model suggests searchers have been looking in the wrong place.”

Almost five years after the airplane, passengers and crew disappeared (March 8, 2014), a Danish engineer named Martin Kristensen at Aarhus University in Denmark, published new analysis from the original search data.

After recrossing over its own track, the airliner’s path became confused by hourly location requests by the geostationary satellite, Inmarsat 3F1; these were ignored by the airliner. MH370 crossed through seven circle areas, but the points in each circle where the airliner crossed were vague. Based solely on these satellite breadcrumbs, the two extensive search patterns were planned using these tenuous plots.

Kristensen suggested that the searchers were looking in the wrong place. Based on aligning airliner movement with satellite movement created several Doppler shifts. From here Kristensen’s science becomes intense resulting in four separate solutions, of which three have been discounted. The fourth puts the plane near Christmas Island in the Indian Ocean within a search pattern that is eighty-seven miles long by nineteen miles wide, thousands of miles from the original search areas.

The MH370 investigation was a collection of mistakes. A lack of proper leadership, too many experts floating their opinions without fact and overwhelmed search crews looking for a needle in a warehouse full of haystacks. For months following the disappearance, debris continued to wash up on surrounding island shores; the items arrived erratically and not all could be confirmed to be from the doomed airliner.

What is the harm in allowing yet another unproven act to follow the last bad acts in this tragedy? Aside from the tragedy of losing so many innocent lives, the families’ grief played out daily for months. False hope after false hope dashed victims’ family members’ expectations that answers to their loved ones demise would be found. This is not some small cross to bear; from the humanity standpoint, it is unnecessary and cruel.

Aircraft lost during war have been obscured from detection – often within months – by snow, ice and jungle overgrowth. Uneven land masses such as valleys or trenches have not only hidden the aircraft, but deformed them from anything recognizable, tearing off wings, empennages and engines. Indigenous tribes have stripped seats, unit load devices and exterior panels for making homes, while the animals have erased all trace of human remains. This is what happens to wreckage above sea level.

Aircraft lost beneath the waves are subject to worse mysteries. The ocean floor is as flat as the Rocky Mountains; crevasses and steep mountain peaks that rival Mount Everest can be found anywhere under the ocean surface. Ocean currents that are stronger than hurricane winds can move the parts of an aluminum and composite frame miles from conjoining parts of the same aircraft; these currents alter direction as one goes deeper.

The HMS Titanic was one such mystery that, even with technology at the time, eluded detection. Here was a ship that weighed, in total, 46,300 Gross Register Tons and it sank to a depth of 12,500 feet. The Titanic didn’t break up on the surface like an aircraft might; it slipped beneath the waves in two pieces, the bow 470 feet long by 92 feet wide, the stern 410 feet long and 92 feet wide. Currents had little effect on the two hull pieces, yet they managed to land one third of a mile apart. Despite the unquestionable makeup of iron material and the sheer size of each half, the ship avoided detection for decades.

The Boeing 777 is 210 feet long, 200 feet wingtip-to-wingtip, fully intact; it can weigh 600,000 pounds when operating. The structure is made mostly from aluminum and composite materials, very light. However, the fuselage is largely hollow, which makes it compressible.

Technically, impacting the ocean surface is akin to hitting something solid. Water is a liquid; it is not compressible; water does not give way as quickly as a gas, but, like a solid, resists motion. If MH370 had hit the ocean surface at an uncontrolled cruising speed of 550 miles per hour (MPH), the aircraft would have broken into many large and small pieces, depending on impact angle. As the fuselage’s forward momentum carried it below the surface, the tail was still moving at the impact speed. When the nose rapidly slowed toward zero; the hull collapsed nose to tail; the crown and belly explode outward, vomiting seats, luggage and electrical aircraft components in every direction. Each wing with its 11,000 pound engine, most likely separated from the hull, as would the vertical and horizontal stabilizers. Large sections of aircraft, weighed down by heavy components, e.g. landing gear or engines, would have sunk quickly, spiraling in their descent, sliding with the current.

On August 26, 2003, a Colgan Airways Beech 1900D, operating as US Air Express flight 9446, crashed shortly after take-off from Yarmouth, MA, airport. The aircraft hit the ocean surface at a steep angle, 300 yards from shore, with a speed of 115 MPH. Pictures in the accident docket for NYC03MA183 demonstrate the catastrophic results of an aluminum airliner hitting the ocean at one hundred MPH. The fifty-eight foot long airliner broke into multiple pieces. When laid out, wreckage took up a hangar floor section one hundred thirty feet long by eighty feet wide. The empennage was unrecognizable; the vertical stabilizer was twisted, compressed and folded along the tail. Insulation, wiring, seats and broken sections of wing or fuselage laid beside landing gear, engines and instrumentation.

Assuming Martin Kristensen is successful in determining the exact flight path of MH370, recovery of the wreckage will be impossible. Any human remains have long disappeared; if not dismembered by impact forces, any remains would never have survived intact after five years at sea. The fuselage sections have either been carried away by currents or given to erosion. According to the depth, they could be concealed by marine life or covered with silt. Other sections could have been lost between hills or fallen into underwater valley. The flight recorders’ flight data has become unrecoverable.

The theories for locating MH370 or any wreck should be tried; if nothing else, new discoveries in recovery will only assure future tragedies can be solved, that victims’ families will find peace of mind. However, these attempts to save the day with new technologies are better tested under less conspicuous conditions, without involving the whole world in a possible failed attempt. The original investigation was a bad act, fraught with failure. Do we have to drag the families through this again for someone’s fifteen minutes of fame?

Aircraft Accidents and Lessons Unlearned XX: LAS Registration Number HK-4246X

When Flying Tiger and Seaboard World premiered in the 1940s, air cargo carriers were considered the ‘Pinnochios’ of aviation, meaning they were never considered ‘real’ airlines by the aviation industry. Even with the dawn of Federal Express’s overnight package delivery, air cargo rarely enjoyed recognition from the passenger versions of the jet age. These are not bizarre statements; the lack of recognition extended to accident investigation, where cargo carrier safety was viewed as unimportant when compared to passenger carriers. The belief that, “It’s only three pilots and a bunch of boxes,” generated little concern and less attention. Indeed, air cargo accidents rarely made the front page.

At the turn of this century, the National Transportation Safety Board (NTSB) continued to downplay cargo aircraft accidents; victim count always fell below public notice. However, cargo aircraft accidents deserved the airline industry’s full attention; we ignored these air carriers at our own risk.

Why? Because air cargo accidents involve the same equipment used by passenger carriers, often under identical flight operating conditions. Because cargo profits were greater, many operational advances were developed in all cargo environments. Cargo airlines shined an embarrassing light on what issues made passenger operations less safe. Finally, accidents were often due to the unexpected; small anomalies that grew into larger issues. Some accidents took us in directions never imagined.

On December 18, 2003, a Lineas Aéreas Suramericanas (LAS) DC-9-15F, tail registration HK-4246X, crashed in the jungles between Bogota and Mitú, Colombia. Onboard were two pilots and a mechanic; the cargo was four 5000-pound pallets of bagged concrete. The thirty-seven year-old airliner (manufactured as a cargo aircraft) was approaching Mitú from the northeast, the aircraft suddenly plummeted from 23,000 feet after executing a right turn.

Because the crash site was in the jungle bordered by the drug cartel, rescuers were only able to remove the three bodies, the cockpit voice recorder (CVR) and the flight data recorder (FDR) – none of the aircraft was recovered. The NTSB only assigned one maintenance investigator (MI) as the sole accident investigation liaison to Colombia, to help them investigate the accident. A recorder analyst was also assigned to interpret both the CVR and the FDR. The Federal Aviation Administration (FAA) sent an experienced accident investigator, who took lead in dealing with the Colombian government in protecting the team from the drug cartel.

Since this investigation was supportive, it wasn’t accomplished like a normal launch; the three investigators first met with NTSB management and Colombian representatives. The recorder investigator presented early interpretations of the CVR and FDR findings, which showed a complete loss of all flight and engine controls. Since the accident aircraft was never recovered, the lack of physical evidence had to be compensated for by an onsite inspection of a sister aircraft in the LAS fleet.

After meeting with the Colombian officials, the NTSB Director resolved that, in order to prevent an imaginary Horizontal Trim Stabilizer Jackscrew failure ‘epidemic’, the LAS DC-9-15F’s horizontal trim stabilizer jackscrew ‘failure’ was the cause of the accident. The Director ordered the MI to include this fabrication into the NTSB’s report to support his unrealistic effort to pressure the FAA to require redundant jackscrews in all past and future jet aircraft.

NOTE: On January 31, 2000, Alaska Airlines flight 261crashed. The Alaska Air MD-83’s horizontal trim stabilizer jackscrew was serviced with an unapproved lubrication grease. This caused the MD-83’s jackscrew to seize in flight, thus contributing to the accident.

However, as the NTSB investigator, I could not corrupt the accident’s findings, even in the pursuit of another end. Instead, the FAA investigator and I went to Bogota to examine the LAS ramp and the sister DC-9-15F cargo aircraft that was there.

While observing the load and offload of the DC-9-15F, it became obvious that the DC-9-15F’s main cargo doorframe suffered damage. Normally, cargo doorframe damage is to the frame’s sides, e.g. torn seals or metal being scratched/bent by careless cargo handlers. In this case, the damage was to the main cargo doorframe’s upper edge. This would be from consistently raising the cargo loader too high during freight movement; normally not impossible, but very unlikely.

The two investigators looked under the cargo floor for anything that could have led to a complete loss of flight and engine controls. In pre-digital technology aircraft, the control cables for the flight controls and the engines ran under the floor, from the cockpit to wing box (ailerons, flaps, spoilers) to tail (elevators, rudders, horizontal trim, engines). Routing beneath the floor was the only place all the controls shared.

The underside inspection was, initially, a dead end; the floor was supported by structure. The floor’s cargo locks, which translate cargo loads into the aircraft’s structure, appeared to be in the correct positions; the locks looked to take the heavy loads properly … from what could be observed. However, when discussing the floor layout with the ramp supervisor, it was learned that the LAS DC-9-15F, leased from an American air operator: Kitty Hawk Airlines, had eight standard unit load device (ULD) positions on its upper deck cargo compartment. A standard ULD’s dimensions were: 88 inches wide by 125 inches long by 79 inches high.

The manufacturer of LAS’s leased DC-9-15Fs – McDonnell Douglas Aircraft – certified the DC-9-15F with seven ULD positions. A position had been added; this would require a review of any supplemental type certificate (STC), an alteration to the original manufacturer’s designs, to the cargo floor.

Before leaving Bogota, an inspection was made to the upper deck and why the ULDs were hitting the cargo doorframe’s upper edge. It was found that the floor was altered to allow an eighth ULD, but that a new floor was placed on top of the original floor and secured. This extra floor created the height that made the ULDs strike the upper doorframe.

The two investigators then went to Evergreen Airlines in Portland, Oregon; Evergreen owned the DC-9-15F that was manufactured next to the accident aircraft in 1966. Built as a cargo airliner, this aircraft had the original seven position floor layout. This allowed for floor measurements to be made, using the STC’s dimensions to check against the original design.

Comparing the original cargo floor plan, to the altered cargo floor plan with a DC-9 structural layout, it was clear that the accident aircraft’s cargo locks did not align with the aircraft’s structure; the stresses that were normally transmitted into the airframe, instead, were transferred to the weak floor; no structural strength had secured the cargo. Based on this STC data, the known cargo weights caused the floor to rupture. At that failure point, all engine and flight control cables were arrested. Without the accident aircraft to verify this, the only way to check this theory was to compare the CVR and FDR timelines.

In Washington, DC, a second meeting between the Colombian officials and NTSB management was held. The updated CVR and FDR data was compared. The CVR recorded a ‘bang’, a loud unnatural noise of structure tearing. The CVR technicians determined, employing digital analysis, that the loud sound was fifteen to twenty feet behind the cockpit bulkhead where the freight was. The ‘bang’ came the exact moment all control cable movement ceased. The MI and the FAA investigator tied the recorded noise and the seized cables to the STC engineering flaw that allowed the cargo locks to be unsupported by the aircraft’s structure, that one of these locations was most likely the point where the floor failed.

Since no formal NTSB report was written, NTSB management dismissed the findings since the horizontal trim stabilizer jackscrew failure was omitted as the cause. NTSB management refused to list this LAS DC-9-15F accident in the NTSB Archives. However, the FAA investigator pursued the STC engineering issue from the FAA’s side; there were sister aircraft with the error written STC being flown in the United States. They represented a safety hazard.

It was by a cargo aircraft accident that a major alteration of a common airliner was determined to be unsafe, indeed fatal. With airlines looking to fit as many passengers and freight inside the aircraft, this Lessons Unlearned proved that redesigns, when done incorrectly, can kill.