Archive for November, 2018

New MH370 Debris Suggests a High Speed Impact

 

Blaine Gibson holds new MH370 debris, accompanied by a fisherman who found the part in Madagascar

Today Blaine Gibson and other MH370 family members delivered to Malaysian authorities five new pieces of debris that are believed to be from the missing aircraft. The parts were found as a result of a campaign led by Blaine and the families to make the residents of Madagascar more aware of debris from MH370 that has drifted across the Indian Ocean and continues to land on the shores of East Africa.

Blaine has provided photographs and descriptions of the five parts, which are made available here in a zipped file. More recent high-resolution photographs are available here. The most recently discovered part (Part 5), pictured above, was found by a local fisherman this past August.

One piece of debris (Part 3) was identified by MH370 Independent Group (IG) member Don Thompson as a shattered piece of the interior floorboard of a Boeing 777. The part’s location in the B777 and the nature of the damage is consistent with a high speed impact, and therefore has probative value.

Fragment of floorboard of MH370

Identification of the Floorboard Piece

IG members Don Thompson and Mike Exner assisted Blaine in identifying the floorboard piece, and Don documented his findings in a report. An important clue was the piece contained a portion of a placard with the identifying characters WPPS61. Don was able to determine that the full placard number is BAC27WPPS61. This type of placard is affixed to high strength panels of material specification BMS4-20, which is used as flooring  material in passenger compartments of commercial aircraft, including the Boeing 777-200ER. Amazingly, Don was able to find a similar placard affixed to the floorboard of wreckage from MH17, which was also a Boeing 777-200ER. This leaves little doubt that the piece recovered from Madagascar is from MH370.

Portion of floorboard placard showing characters WPPS61

Discussion

The new debris gives us additional insight about where and how the aircraft impacted the sea. In light of the past efforts to find the aircraft, there are three main possibilities that remain:

  1. The aircraft impacted the ocean relatively close to the 7th arc, but at a latitude further north than the area previously searched.
  2. The aircraft impacted the ocean at a latitude previously searched, but farther from the 7th arc than previously assumed.
  3. The aircraft debris field was in the subsea area previously scanned by sonar, but was either missed or misidentified.

Sources close to the previous search effort believe (3) is very unlikely, as there was a thorough review of the sonar data by multiple parties with high levels of experience, and because any “points of interest” were scanned multiple times to ensure the resolution was adequate to make a determination with a high level of confidence.

When considering the satellite data, the final two BFO values at 00:19 UTC are consistent with an aircraft at an increasingly high rate of descent. The new debris and some of the previously recovered debris also suggest that the aircraft impacted the ocean at high speed. That means that (2) is possible only if the aircraft first was in a rapid descent (producing the final BFO values), and then the pilot skillfully recovered from the rapid descent and glided some distance away from the 7th arc beyond the width of the subsea search, and then later the aircraft again descended at high speed and impacted the sea (producing the shattered debris). This sequence of dive-glide-dive is considered by many to be a very unlikely sequence of events, although it cannot be completed dismissed.

What is left is possibility (1). This suggests future subsea search efforts should proceed along the 7th arc, starting where the last search ended near 25S latitude, and continuing farther north. (In a previous blog post, I showed that an automated flight ending along the 7th arc at 22S latitude is possible.)

The part recovered in Madagascar in August 2018 was the latest in a series of finds that began with the discovery of the flaperon on Reunion Island in July 2015. Because of the wide range of discovery times, and because there is an undefinable delay between when a part arrives on a beach and when it is discovered, it is difficult to use the timing and location of debris discoveries to precisely pinpoint where to search for MH370.

Finally, the new debris finds illustrate the critical role of independent investigators in the search for MH370, and one investigator in particular. The local communications campaign to educate residents of Madagascar about debris washing ashore was spearheaded by Blaine Gibson with the help of some of the MH370 families. Blaine has also done a commendable job of developing a local network to help recover the debris after discovery. We have to wonder if additional debris is sitting on the shores of other countries like Tanzania, Kenya, and Somalia, where there were no similar campaigns to alert and organize the residents.

Links in this article:

Photographs and description of debris provided by Blaine Gibson

Additional high resolution photographs of debris

Identification of the piece of floorboard by Don Thompson

Reconstructed path ending near 22S latitude by Victor Iannello

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Ocean Infinity Finds Argentine Submarine, After Not Finding MH370

Sonar image of the debris field of the ARA San Juan (Armada Argentina).

About one year after its disappearance, one of Ocean Infinity’s (OI’s) autonomous underwater vehicles (AUVs) has detected the remains of the missing Argentine submarine, the ARA San Juan. From Ocean Infinity’s website:

Ocean Infinity, the seabed exploration company, confirms that it has found ARA San Juan, the Argentine Navy submarine which was lost on 15 November 2017.

In the early hours of 17 November, after two months of seabed search, Ocean Infinity located what has now been confirmed as the wreckage of the ARA San Juan. The submarine was found in a ravine in 920m of water, approximately 600 km east of Comodoro Rivadavia in the Atlantic Ocean.

Oliver Plunkett, Ocean Infinity’s CEO, said:

“Our thoughts are with the many families affected by this terrible tragedy. We sincerely hope that locating the resting place of the ARA San Juan will be of some comfort to them at what must be a profoundly difficult time. Furthermore, we hope our work will lead to their questions being answered and lessons learned which help to prevent anything similar from happening again.

We have received a huge amount of help from many parties who we would like to thank. We are particularly grateful to the Argentinian Navy whose constant support and encouragement was invaluable. In addition, the United Kingdom’s Royal Navy, via the UK Ambassador in Buenos Aires, made a very significant contribution. Numerous others, including the US Navy’s Supervisor of Salvage and Diving, have supported us with expert opinion and analysis. Finally, I would like to extend a special thank you to the whole Ocean Infinity team, especially those offshore as well as our project leaders Andy Sherrell and Nick Lambert, who have all worked tirelessly for this result.”

Ocean Infinity used five Autonomous Underwater Vehicles (AUVs) to carry out the search, which was conducted by a team of approximately 60 crew members on board Seabed Constructor. In addition, three officers of the Argentine Navy and four family members of the crew of the ARA San Juan joined Seabed Constructor to observe the search operation.

Ocean Infinity had committed to conduct the search operation for up to sixty days, and to take on the economic risk of the search, only receiving payment if the submarine was found.

Position Estimates from Acoustic Measurements

The debris field is centered at (-45.9499,-59.7730). Meanwhile, after analyzing the hydro-acoustic data from CTBTO sensors that was collected on Nov 15, 2017, the hot-spot was estimated to be centered at (-46.12,-59.69). That’s a distance of only 20 km, which is an impressive demonstration of the capabilities of the hydro-acoustic analysis.

There was a test explosion on Dec 1, 2017, that was used to calibrate and verify the position estimation model. The position error of the test explosion was 37 km. Therefore, the position error for the debris field was well within what was expected based on the test explosion.

An interesting description of the CTBTO’s hydro-acoustic analysis is presented here.

Implications for the Search of MH370

Unfortunately, the acoustics generated by the impact of MH370 on the ocean surface would not propagate along the “deep sound channel” (DSC) the way an underwater acoustic event does, so the impact likely was not detected by CTBTO sensors.

The San Juan’s debris field was detected earlier this month only after an AUV mission was conducted in a deep trench that was previously scanned from a higher altitude in September. The ability to skim about 100 meters above the challenging surface contour allowed the side scan sonar sensors in the AUV to collect data at the proper altitude to achieve the required image resolution. Because of its limited ability to glide above steep slopes, this resolution would have been very difficult to achieve using a “towfish”, which is a cable-towed underwater vehicle that is similarly equipped with side scan sonar sensors, but is much more limited in maneuverability than an AUV.

The initial seabed search for MH370 was conducted by the vessels Fugro Discovery, Fugro Equator, and GO Phoenix, each using a towfish. These vessels scanned about 120,000 square kilometers of seabed using this technology. Based on the failure of OI to detect the San Juan’s debris field until an AUV mission was conducted in a trench, we have to at least consider the possibility that that the debris field for MH370 was passed over in the initial search but was not detected due to challenging terrain.

In the coming weeks, we’ll learn more about what worked and didn’t work in the search for the San Juan. That knowledge should be applied to MH370 to determine if we can confidently eliminate all of the seabed that has been previously searched.

Update on November 18, 2018

The ATSB did provide statistics for estimating the confidence of detecting MH370 in the 120,000 square kilometers that were initially scanned primarily by towfish. Those statistics are presented in the figure below. About 97.4% of the total area had a detection confidence of 95%, based on the ability to detect a debris field with dimensions of 100 meters by 100 meters. About 2.1% of the area had a detection confidence of 70%, mostly due to difficult terrain, environmental conditions, or degraded data. About 0.5% of the area had no data. The aggregate probability to detect MH370 in the 120,000 square kilometers is therefore about 94%. Although this is high, it is not 100%.

Don Thompson and Mike Exner provided helpful comments for this article.

Area coverage statistics for the ATSB seabed search (ATSB).

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Crash Debris from Lion Air JT610 Provides Clues about MH370

Lion Air flight JT610, with 181 passengers and 8 crew, was climbing out of Jakarta on a flight to Pangkal Pinang (Indonesia) when control was lost at around 5,000 ft. Soon after, the Boeing 737-MAX 8 aircraft crashed into the Java Sea northeast of Jakarta. Although we don’t know the cause of the crash, there were some anomalies noted on the previous flight related to sensor disagreements for speed and altitude which required maintenance. Some suspect that these previous issues might have been related to the crash. Luckily, the flight data recorder (FDR), commonly known as a “black box”, was recovered, and the approximate location is known for the cockpit voice recorder (CVR), the other “black box”, so there is a good probability that the cause of the crash can be determined.

Investigators are now claiming they have recovered 69 hours of data from the FDR, which would be sufficient to analyze JT610 as well as the preceding flight which had the anomalous behavior.

The last ADS-B data that we have from Flightradar24 has the aircraft at an altitude of 425 ft, a groundspeed of about 360 knots, and a descent rate of 30,976 fpm. That translates to an approximate true airspeed of 472 knots and a descent angle of about 40 deg. That suggests the aircraft impacted the sea with very high energy. Similarly, the final BFO values for MH370 suggest a downward acceleration of about 0.7g over 8 seconds, reaching a descent rate of about 15,000 fpm. Unless a pilot was at the controls and skillfully recovered from this descent, MH370 also impacted the sea with high energy. Therefore, the debris produced from the JT610 crash gives us some indication of the types of debris probably produced from the crash of MH370.

Indonesia’s National Search and Rescue Agency (BASARNAS) is in charge of the rescue and recovery operation for JT610, which is in water about 100 feet deep, with efforts reportedly hampered by strong underwater currents and limited visibility. Already one volunteer diver has lost his life while recovering body parts.

The video at the top shows floating debris for JT610. If the objects shown are truly representative of the main field of floating debris, it is evidence that a high speed impact produces only small floating parts spread over a fairly limited area. Now admittedly, a B777 is considerably larger than a B737, and the floating debris field should be easier to find. However, the surface search for MH370 in the Southern Indian Ocean (SIO) from the air began weeks after the disappearance, and the dispersive effects of waves and currents in the SIO are strong. The combination of a dispersed field and small parts might explain the failure for the air search to detect floating objects along the 7th arc. The small size of the floating parts might also explain why satellite images along the 7th arc have not spotted aircraft debris.

Despite the likelihood of small floating debris, the underwater searchers for MH370 expect to find a fairly substantial debris field (bigger than 100 m) and substantial, distinguishable objects such as the landing gear and engines, consistent with the debris field of Air France 447. This is also consistent with the parts of JT610 that have already been found on the seabed. For instance, the picture below shows an engine and part of the landing gear of JT610.


To locate parts on the seabed, BASARNAS is using a combination of technologies, such as multi-beam echo sounders (MBES), side-scan sonar (SSS), magnetometers, and remotely-operated vehicles (ROV). The SSS technology has been the workhorse for the subsea search of MH370, used in both the towed vehicles and the underwater drones.

The video below shows divers helping to retrieve debris from the seabed.

The debris recovered from the crash of JT610 helps explain why no MH370 floating debris was spotted by air and by satellite along the 7th arc, and why we remain hopeful that it will be detected on the seabed with sonar sensors once the correct search area is selected.

Update on November 13, 2018

Here’s a Wall Street Journal story that discusses the stall-protection system that likely led to the crash of JT610.

Boeing Withheld Information on 737 Model, According to Safety Experts and Others

Data related to a new flight-control feature suspected of playing a role in crash in Indonesia

By Andy Pasztor and Andrew Tangel
Nov. 12, 2018 11:16 p.m. ET

Boeing Co. withheld information about potential hazards associated with a new flight-control feature suspected of playing a role in last month’s fatal Lion Air jet crash, according to safety experts involved in the investigation, as well as midlevel FAA officials and airline pilots.

The automated stall-prevention system on Boeing 737 MAX 8 and MAX 9 models—intended to help cockpit crews avoid mistakenly raising a plane’s nose dangerously high—under unusual conditions can push it down unexpectedly and so strongly that flight crews can’t pull it back up. Such a scenario, Boeing told airlines in a world-wide safety bulletin roughly a week after the accident, can result in a steep dive or crash—even if pilots are manually flying the jetliner and don’t expect flight-control computers to kick in.

That warning came as a surprise to many pilots who fly the latest models for U.S carriers. Safety experts involved in and tracking the investigation said that at U.S. carriers, neither airline managers nor pilots had been told such a system had been added to the latest 737 variant—and therefore aviators typically weren’t prepared to cope with the possible risks.

“It’s pretty asinine for them to put a system on an airplane and not tell the pilots who are operating the airplane, especially when it deals with flight controls,” said Capt. Mike Michaelis, chairman of the safety committee for the Allied Pilots Association, which represents about 15,000 American Airlines pilots. “Why weren’t they trained on it?”

One Federal Aviation Administration manager familiar with the details said the new flight-control systems weren’t highlighted in any training materials or during lengthy discussions between carriers and regulators about phasing in the latest 737 derivatives.

Boeing declined to immediately answer specific questions Monday. “We are taking every measure to fully understand all aspects of this incident, working closely with the investigating team and all regulatory authorities involved,” the company said in a statement. “We are confident in the safety of the 737 MAX.”

On Monday, an FAA statement reiterated that the agency had mandated flight manual changes to emphasize proper pilot responses to the new flight-control systems. “The FAA will take further action if findings from the accident investigation warrant,” the statement noted, but declined to comment further.

Boeing marketed the MAX 8 partly by telling customers it wouldn’t need pilots to undergo additional simulator training beyond that already required for older versions, according to industry and government officials. One high-ranking Boeing official said the company had decided against disclosing more details to cockpit crews due to concerns about inundating average pilots with too much information—and significantly more technical data—than they needed or could digest.

Minutes after takeoff from Jakarta in good weather, Lion Air Flight 610 experienced problems with airspeed indicators and a related system that feeds data to computers about the angle of the nose. The crash killed all 189 people on board.

Investigators haven’t described the precise sequence of events that caused the twin-engine jet to plummet into the Java Sea at a steep angle and high speed. But Indonesian authorities already have called for stepped-up pilot training and suggested they are delving into design issues. In the U.S. at least, substantial training changes will have to wait until new flight simulators are delivered to carriers.

The focus of the probe is shifting away from its early emphasis on individual system malfunctions and suspected pilot mistakes, according to people tracking developments.

Instead, these people said, U.S. and Indonesian crash investigators increasingly are delving into the way the MAX 8’s automated flight-control systems interact with each other, and how rigorously the FAA and Boeing analyzed potential hazards in the event some of them malfunction and feed incorrect or unreliable data to the plane’s computers. Swiftly turning off the automated feature is the solution in such cases.

Earlier 737 versions have different stall-protection systems, that don’t automatically drive down the nose even when other functions of the plane’s autopilot are turned off.

Yet operation of those older systems was highlighted in training over the years, and pilots had to memorize steps to counteract potentially dangerous unintended consequences. MAX 8 training materials don’t include a requirement to memorize the steps to turn off the stall-protection system.

Stepped-up scrutiny of the latest 737 MAX features applies to more than 200 of the models that have been delivered to customers around the world, including Southwest Airlines , American Airlines and United Airlines. Boeing’s 737 factory near Seattle currently churns out 52 planes a month.

“We’re pissed that Boeing didn’t tell the companies and the pilots didn’t get notice obviously, as well,” said Capt. Jon Weaks, president of Southwest Airlines Co.’s pilot union. “But what we need now is…to make sure there is nothing else Boeing has not told the companies or the pilots.”

Like Mr. Weaks, some FAA managers and industry officials aren’t satisfied with what they contend is Boeing’s belated candor.

Boeing is working on a software fix, according to industry and government officials, that would likely mitigate risks. On Saturday, the company went further than before in spelling out dangers pilots can face if they misinterpret or respond too slowly to counter automated commands.

In a message sent to all 737 operators, and reviewed by The Wall Street Journal, the Chicago plane maker explained in painstaking detail the engineering principles and operational parameters behind the latest automation.

That message was more detailed than the bulletin Boeing voluntarily issued earlier, alerting pilots about the potential hazard—and touching off debate over the stall-prevention system’s design. Within hours, the FAA followed up with its emergency directive mandating changes in flight manuals.

Such interim efforts “are very appropriate in the near term to increase pilot awareness,” said John Cox, a former 737 pilot and ex-crash investigator for North America’s largest pilots union who now consults on safety for carriers and business aviation.

Boeing’s latest communications with airlines prompted American’s union to alert its members. “This is the first description you, as 737 pilots, have seen,” the union pointedly told pilots in a memo, referring to the 737 MAX stall-prevention system. Noting the system wasn’t mentioned in American Airlines’ or Boeing manuals, the union memo added: “It will be soon.”

The ultimate way to counteract dangerous automated nose-down commands is basically the same for old and new systems, though checklists and procedures for the 737 MAX 8 entail more steps and take more time. Investigators and safety experts are convinced that as the emergency worsened, the Lion Air crew had barely seconds in which they could have diagnosed the problem and taken action to save the aircraft.

Shortly before the plane crashed, according to local Indonesian media reports, one of the pilots told air-traffic controllers about difficulties controlling the plane.

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