What Happened to MH-370?

On 8Mar2014 Malaysian Flight MH370 took off from Kuala Lumpur for Beijing at 00:41am local time. Last voice contact with the aircraft occurred at ~ 1:15am; radar contact was lost at 02:15am. The plane was due to arrive in Beijing at 06:30am, but never made it. Fortunately Inmarsat personnel were able to receive “handshake” signals every hour until 08:11am. A ‘partial handshake’ was perhaps registered at ~ 09:00am. Ever since, the world has been searching the oceans.

Initially aircraft searches focused on the Gulf of Thailand, then the North Indian Ocean, and finally the South Indian Ocean. The aircraft recovery team, headquartered and led by the Australians, is run from the Perth area.  The plane is now believed to be down somewhere west of NW Australia. The team focused first on the Indian Ocean, some 1700nm SW of Perth. Next the search area moved to 900nm West of Perth, and now, augmented with a series of underwater pings from the plane, the focus is centered about 21.1S, 104E (1080nm NW of Perth). It’s certainly been a dramatic shift in search areas over the past month!

The team directs its searches based upon Inmarsat team analysis in UK and the detected locations of the sonic pings emanating from the lost sitting on the ocean bottom.

The Inmarsat search areas are calculated using a clever “Doppler-Shift” technique. Because the Inmarsat F3-1 is a GSO (Earth Stationary Orbit) satellite that rotates around the Earth every 24-hours (the same as the earth’s rotation), it appears to be suspended motionless in the sky above the same spot (called a subpoint) over the Earth at all times: zero Latitude (Equator) and 64.5-deg East Longitude. To achieve satellite and earth rotational synchronicity, it’s located almost three Earth diameters above the Equator over the Indian Ocean. See below.

The Inmarsat F3-1 satellite has responsibility for handling all sorts of Earth communications with Inmarsat that originates from the Indian Ocean area: ships/aircraft, etc.

Even though the MH370 shut down its data link with the world very early in flight, the Inmarsat team has been able to progressively refine the estimated location of the aircraft splashdown. It turns out the satellite never gave on the plane, even after it shut down all its transmissions. Every eleven minutes past the hour the satellite attempted to contact the plane. It would emit a ‘handshake’ signal (“ping”) to the plane to inquire if it were still there. Once the plane heard the ping, it automatically responded with a “Yes I am here” signal of its own. The plane knew nothing else to say, as its brain was no longer engaged with the world. The satellite received the signal about a tenth of a second later. (That’s how quickly the signals travel going at the speed of light.) The Inmarsat then down linked the ‘handshake’ signals to ground and in short order the ‘up/down’ communication was in the hands of Inmarsat Operation’s Centre in England.

First the team analyzed each of the handshake signal trip times from satellite to MH370 and back again. They were then able to estimate where the plane was at eleven minutes past each hour, until the plane finally splashed and sank (after the 08:11am handshake) in the Indian Ocean. For each handshake they constructed a circular ring, centered on the 3F-1’s Earth’s sub-point (Lat 0.0, Long 64.5E). They repeated this procedure for each handshake (ping). The final result was a series of concentric circles, indicating the plane’s distance from the sub point as a function of time. By itself, this was not very insightful data. Next we assume that the plane was flying at low altitude flight conditions, say 315 KTAS at 35,000-ft (35kft).

(Note, I’m using the units of measure that pilots use.  KTAS (Knots True Air Speed, it has units of nautical miles per hour, or nm/hr.)  This unit of speed is similar to mph, but uses a nautical mile (nm = 6067ft) rather than a statute mile (sm  = 5280ft).

Also we assume the pilot flew a series of one-hour, straight-line segments. In one hour the plane could reach anywhere along the dotted, white circle, as shown. We look for an intersection between the dotted circle and the handshake arcs. A straight line is drawn from the initial location to the the intersection point. We repeat the process for each handshake. In this way, we can create a possible MH370 flight path consistent with both constraints.

Our results, shown below, have evolved slowly as better data and refined assumptions were input. Observe that the assumed aircraft speed makes a very large impact on where its position is at the 08:11am handshake. 

Still it took three weeks before they estimated the plane’s splashdown occurred 900nm West of Perth. Then on  5Apr2014, the Chinese detected a sound ping from one of the black boxes. That detection turned out to be erroneous. But, several days later, Australian ships detected four clustered sound pings emanating from the sunken aircraft, off NW Australia (see above). It is the 300KTAS (dotted, yellow track) that I will show best matches the flight scenario. But, to date no one has suggested this low speed?  It is this speed uncertainty that first got my attention. Apparently there was a range of 300-450KTAS to place the plane at one of the suspected splash areas. Interestingly the B-777 cruises comfortably at between 450-475KTAS. So what is going on?

And that is where the situation stands today, 11April2014. The expectation is that further triangulation of the sound ping’s origin will further reduce and refine the search area. At such time, UAVs (Underwater Autonomous Vehicles) will slowly map the sea floor, eventually locating the aircraft and its all-important black boxes (voice and data recorders).

While this scenario plays out, I am attempting to further examine the MH370 flight path and its flight characteristics to see if additional clues might suggest themselves as to what the plane might have been up to on that fateful night.

I have poured over numerous reports/charts/maps during the past month to learn all I could. I’ve listed key events that I hold to be mostly  ‘true.’

·   MH370 proceeded normally until it reached the middle of the Gulf of Thailand

·      Final voice contact from Pilot ~ 1:07am local time

·      Someone turned off plane’s transponder and other data links by 1:15am

·      Then the plane made an abrupt left-hand turn, heading back over      the Malaysian Peninsula

·      During this leg, it climbed to above 40kft and then descended to under 5kft.

·    Changed course again turning to a NW heading toward the Andaman Islands, at low altitude, but was unseen by ship traffic in the Malaccan Straits.

·      Malay ground radars tracked the plane ~ 180nm NW of Panang until losing it at 02:15am

·      Doppler-shift analysis suggests the plane made one more left hand turn around 03:35am probably near the Equator and then proceeded on a fairly straight path southward until splashdown (after 08:11 and before 09:00am).

·      Plane flight path was never detected again by ground radar, probably staying West of the island of Sumatra

·       No aircraft debris has yet been located on the sea surface

·      Recent acoustic triangulation places the plane crash site near 21.1S, 104E

·       Splash down occurred after sunrise

My goal has been to pin down the plane’s location when radar track was lost at 02:15am and then to calculate possible flight paths the plane might have taken such that at around 08:11am it (1) was in the vicinity of the latest sonar pings; (2) was along the proper Inmarsat ring; (3) was flying at a reasonable speed and altitude; and (4) had not already run out of jet fuel. Of course, this is not any different than the Australian/Inmarsat search team has been doing.

First, the ping location and Inmarsat 08:11am ring are on top of each other. That’s very comforting. This implies that the plane must have splashed at very close to the 08:11am handshake or that the plane circled over the area for another 45-minutes before crashing at the 09:00am partial handshake. 

The other piece of data I used was a Doppler-Shift analysis to understand when and how fast the plane was approaching/moving away from the Inmarsat's sub point. Positive Doppler velocity means than the plane is moving farther away; negative doppler velocity, it's approaching. Note that the aircraft flies away from the satellite up until ~1:20am local, when it suddenly executes a sharp turn back (-500 KTAS). For the next hour and a half, MH-370 performs a series of slight turns, but continues to approach the satellite sub point. Then the plane's motion begins to approach a zero doppler condition, when it remains at approximately the same distance from the sub point. The plane then makes a left-turn at about 03:35am, implying the plane began flying in a slightly more SSE heading toward the splash area. As the plane enters the Southern Hemisphere, the Doppler  becomes positive, meaning it is now moving away from the satellite. The Doppler remains positive until aircraft splash down. 

After combining these factors, I estimated that MH370 must have averaged about 300KTAS (Knots True Air Speed) along this 2000nm route. This is far slower than the normal 470KTAS (540 MPH or Mach 0.82) usually flown on commercial air routes. If the pilot had flown at his normal speed he would have arrived at the splash down location several hours too early. Alternately, the pilot would have needed to take a very zigzag route at the higher speed to get there on time. The Doppler analysis indicates that this did not happen. Observe the long straight-line flight path segment in the chart extending from 03:35am until splash down.

If he indeed flew the plane at 300KTAS (345MPH), how did he accomplish it? Commercial jets cruise most efficiently at high altitude (~35kft) at ~ 470KTAS (Mach 0.82). Of course slower speeds are permitted, but the pilot must be careful not to cruise too fast or too slow, especially at this high altitude. Too fast and the plane approaches the high-speed buffet boundary; too slow, and it approaches the low speed buffet limit (See chart below.). This low speed boundary indicates the aircraft, as it slows down, no longer has sufficient wing lift to keep the plane from stalling, and thus falling out of the sky. This may become very dangerous, quickly, as the plane can enter an uncontrollable spin toward Earth. This is very bad!

Infact, the B-777 and all commercial jets cannot cruise at 300KTAS at 35kft, as this speed is well below their stall speed boundary. The chart depicts the safe flight envelope for this aircraft. I have plotted both the low and high-speed boundaries as a function of aircraft speed (KTAS) and altitude Flight altitude kft--thousands of feet above sea level. Note how the two boundaries approach each other as the flight altitude increases. At 35kft observe how narrow the pilot’s speed choices are to remain in the safe fight regime, barely 50 KTAS above/below the recommended speed. 

So what routing did the plane take to get there? The figure below shows my estimate of the plane’s flight path during the first 3.5 hours of the scenario. I assumed that the 02:15am radar break lock occurred prior to the north of the tip of Sumatra at Lat7.5N, 94.5E. 

This is the vicinity where many analyses place the aircraft at the moment it began its flight southward to the splash site. We also know that no radars along the north and west coasts of Sumatra detected the aircraft. In particulate, the large radar at Banda Aceh, on Sumatra’s northern coast did not detect MH370; rather strange to say the least, as the plane should have been within its range at normal flight altitudes.  But MH370 was not at normal altitude.

Radar detection range is in general a function of the aircraft’s flight altitude. Radars typically are instrumented to see out to ~180nm for highflying aircraft, but can only detect  ~85nm for an aircraft flying at 4kft (radar range limited by curvature of the Earth).

For the pilot to cruise at my calculated 300KTAS suggests the plane must have been cruising near 10kft altitude. This would not have been very comfortable ride for the pilot or passengers (?). If true, this is an amazing finding. The flight would be very bumpy/choppy and the pilot would need to continually monitor how close he was the plane’s low speed boundary. One reason to be at this low altitude might have been that no Oxygen would be needed for the pilot/passengers. Does this suggest that the plane had lost cabin pressurization or that the oxygen had been turned off intentionally early in the flight?  Perhaps the pilot also turned off all aircraft lights!

It’s also interesting the plane, even at these very strange flight conditions, would have exhausted his fuel at 08:11am. The plane would have splashed  with the early morning sun shinning. 

Additionally, for some part of his slow flight across the Southern Indian Ocean, the pilot would be nearly on Air Route M641, which is often used for flights between Perth - Colombo, Sri Lanka, and the Persian Gulf.  But at such a low altitude the plane would go unobserved by any commercial plane using that route, especially with all lights off. And there would be no threat of aircraft collision, because of the large altitude separation.

Finally, the splash location is in water that is relatively deep, some 14,000 feet.

 What have I learned doing this? My key findings are summarized below:

 

·          The pilot most probably flew the aircraft all the way to splash down

·       He carefully planned the flight so its loss would not be found, ever! No one assisted him. He  was alone in the cockpit.

·          He may have de-pressurized the cabin to kill the passengers/crew

·      He flew the plane to over 40kft for a short time to insure that everyone was dead. Several minutes would be sufficient

·      There may have been an equipment failure after depressurization, and he was unable to get the Oxygen flowing again

·      So he descended to low altitude so he would not require the plane’s oxygen, He turned off all aircraft lights to avoid being seen over the Malaccan Straits or any where else

·      He piloted the plane to skirt the tip of Sumatra, out of range of the Banda Aceh radar, and then headed south

·      Upon crossing the Equator he turned the aircraft to a heading of 160 deg (SSE) toward NW Australia. I’m not sure why this direction?

·       He flew for 5+ hours along this track at ~300KTAS/10kft.

·      He may have intercepted Air Route 651 for the last portion of the flight

·      Although heading toward Perth, he knew that the plane could not reach it. But he had already planned to splash the aircraft shortly after sunrise off NW Australia. He probably knew/believed that the ocean swells would not be too troublesome at this time and location

·      He executed a power on landing to enhance his probability of success. And importantly, the landing would occur after sunrise. He believed he could execute a pretty smooth intact landing: tail low and plane at normal sink rate at touch down. It was his strong intention to minimize any plane debris/break up on the ocean surface. This was a big gamble, as it would not take much of a swell/chop to cause aircraft break up upon landing. If this happened, there would be debris all over he ocean surface.  He wanted the aircraft to sink intact, descending to the bottom some 14000 ft below, and a very agonizing death for the pilot!

·      If the plane were never discovered, no one would know where/how/why the plane disappeared or who was behind it...

·      In this way his family would receive his insurance money and he could mask why he did it to the world…. Illness or an illicit affair/etc. Wikipedia says:

Shortly after Flight 370's disappearance, media reports revealed that Captain Zaharie Ahmad Shah's wife and three children moved out of his house the day before the disappearance and a friend claimed that Capt. Shah was seeing another woman and the relationship with that other woman was also in trouble. Claims of domestic problems have been denied by Capt. Shah's family. A fellow pilot and long-time associate of Capt. Shah stated the captain was "terribly upset" that his marriage was falling apart.

·                I suspect that he studied/analyzed how best to execute his plan for some time. But apparently he didn’t do (need) much flight simulator time practicing at home.

So that’s my take on this bizarre flight. Obviously there are other possibilities that have merit, too. The real scenario details await the recovery of the MH370 black boxes. Time will tell….