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2014/03/27

MH370 misteries


Flight MH-370 may go down in history as one of most incredible aviation mysteries. The cruel reality is that even though we have a fair amount of information now, we still know so little.
Malaysian Prime Minister Najib Razak informed the families of the victims that the plane had crashed into the remote south Indian Ocean, and all 239 people onboard are presumed dead.
That tragic but not unexpected conclusion was based on data analysis by satellite company Inmarsat, which Malaysia now says was able to track Flight 370 until the signal ended very near where searchers are now hunting for plane wreckage.

The location tells a lot about what might have happened to the doomed flight while telling us not a single detail about why it crashed.
The presumed location of the wreckage makes it all but impossible for certain scenarios to have played out as many observers insisted they must have.
The first thing to understand is altitude is everything. A turbofan powered jet like the Boeing 777-200ER relies on altitude to make good on its ultra long-range capabilities. At its normal cruising altitudes from around 35,000 to 40,000 feet, the 777 can fly very long distances, in excess of 11,000 miles. But it seldom flies long routes.
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On its trip from Kuala Lumpur to Beijing, the plane would have had, according to investigators' projections, around seven hours of total endurance at a normal cruising speed of around 600 mph -- just enough to have flown its suspected flight path north for 40 minutes, west for around that much time again, and then south for many hours.
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At lower altitudes, turbofan engines like the Rolls-Royce engines on the Malaysia Airlines airplane, burn substantially more fuel than they do at typical cruise altitudes -- as much as twice depending on the altitudes one uses for comparison.
The increase in fuel burn will greatly reduce range, making it impossible for Flight MH-370 to have reached the southern Indian Ocean at a low altitude. It would need to have flown at a much higher optimum altitude in order to make it that far.
Pilots can reduce the power to cut back on fuel flow, of course, but that also reduces airspeed, which again reduces range.

There's no winning when it comes to flying a turbofan-powered airplane: If you want to fly far, you need to fly high. So the fuel required for MH-370 to have reached the presumed crash location around 1500 miles west of Perth, Australia, means that the airplane did not do a lot of climbing or descending after it deviated from its original planned route to Beijing while it was still an hour or so north of Kuala Lumpur.
So if there was a struggle for control of the flight -- whether it was mechanical issues or a hijacker -- it could not have lasted long or involved great altitude deviations.
This means it's hard, though not impossible, to explain the disappearance as being the result of a mechanical or electrical failure. Such a scenario, as I've been saying since the beginning of the mystery, would require a kind of mechanical magic bullet, an event that would have taken out the transponder and ACARS radio, as well as the voice communications radios. Why else would they not have communicated the emergency?

Pilot: How mechanical problem could have downed Flight 370
Then one must accept that such a failure chain could then allow the crew -- or skilled intruder-- to be able to drive the airplane around the sky for a protracted period of time, eventually pointing it south, in the opposite direction from where the airplane was originally headed.
Let's remember, too, that the airplane would have to maintain an altitude sufficient to allow it to reach the southern Indian Ocean. All this must also have left the 777 in good enough shape to fly for another six hours or so before crashing.
A failure of the pressurization system might account for the scenario, but only if the pilots completely mismanaged their response to the emergency. The 777's backup and emergency oxygen systems are just as intelligently designed as the rest of the jet's redundant systems.

It's also difficult, if not impossible, to explain how the jet could have made the turns it did if the crew were unconscious during that time. Were they desperately trying to find an airport before time ran out? If so, they would have done two things they didn't do: They would have communicated the emergency and they would have descended. Neither of those things happened. While it's horrific to imagine, a botched hijacking or failed pilot commandeering of the airplane are still the most likely scenarios.
Only when searchers have located and recovered the wreckage, as we all desperately hope they do, will we have our first good clues to what have might have unfolded on Malaysia Airlines Flight MH-370.

Since the disappearance of Amelia Earhart, no aviation search has garnered more attention than the loss of Malaysia Airlines Flight 370. The disappearance has become the mystery of the century. It is baffling both to the public and to aviation experts alike, myself included. First, let's not forget to find compassion for the families and friends of the passengers on board this flight. Accident investigations are aimed at finding them an answer, at discovering the cause of such tragedies and at preventing them from ever happening again.
Rather than delve into the numerous sabotage/terrorist theories, I'd like to focus on mechanical malfunction. Considering all the facts, or the accepted assumption of facts, a malfunction that overwhelmed the crew may still be a viable explanation. This makes the most sense to me, as a 30-year airline veteran.
Piecing together all the current information as of March 24, I'll describe a chronological scenario. The scenario is pure speculation on my part, and I have included commentary at various points.

0. The captain utilizes a PC-based flight simulator and deletes some files. So what? My take: This is a hobby. The captain is passionate about flying. Did he fly only the 777 in the simulator? He could well have flown other types of aircraft in the simulator, for his own purposes. Regardless, he wouldn't require this device to execute a nefarious plot. An 18,000-hour captain already has all the resources, i.e. charts and manuals, including his own experience.

1. The captain completes a cell phone call prior to takeoff. Judging by the distance from the main terminal to the runway, this cell phone call was most likely made after pushback from the gate at Kuala Lumpur. Yes, this was a violation of the sterile period (during which extraneous activity outside of aircraft operations should not occur) and not quite up to professional standards but not a big deal. Most likely, the captain made the call while the airplane had been safely stopped on a taxiway. It does not imply malicious intent. As of this writing, information has not been released regarding the details of the phone call.

2. At 12:36 a.m., Malaysia 370 contacts the Kuala Lumpur tower and receives a clearance to hold short of Runway 32R at the departure end, my translation from a non-verified transcript.

3. At 12:40 a.m., Malaysia 370 receives clearance to take off.

4. At 12:42 a.m., Malaysia 370 receives a clearance to climb to 18,000 feet and is directed to the IGARI waypoint, approximately 300 miles away, the entry point into Vietnam's airspace.
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5. Although the transcript timeline seems abridged, having eliminated communication with other aircraft that had to be on the frequency, it appears that the co-pilot reported the altitude level at 35,000 feet on three occasions. Apparently, this repeated report has caused concern. My colleagues will agree that the most diplomatic method to remind an air-traffic controller that you had requested a higher altitude would be to state your current altitude. It's a subtle hint in air-traffic control parlance. Maybe the original clearance was filed for a higher flight level than 35,000 feet.

6. At 1:07, ACARS (the Automatic Communication and Reporting System) gives what turns out to be its final report. Also at this time, it was alleged that an additional waypoint not on the original flight plan had been entered into the flight management computer. The implication is that someone in the cockpit had intent to veer off-course for nefarious purposes. I believe that if indeed a waypoint was entered -- and it seems difficult to verify with the ACARS no longer reporting -- it was entered as a means to identify an equal-time point. Such a point is a position on the route that indicates the flight is equal in time to two or more diversionary airports. It is a required dispatch calculation prior to departure but an optional entry on the flight management computer.

7. At 1:19, a Kuala Lumpur Center air-traffic controller instructs Malaysia 370 to contact Ho Chi Minh Center (Vietnam radar) on frequency 120.9. The co-pilot responds with the now-famous "All right, good night." Although the correct response would have been to repeat the frequency, the co-pilot was informal. Not a big deal. Crews that have flown that route know that the frequency doesn't change. It is printed on the en route chart.

8. At 1:21, the transponder ceases to send out its coded discrete signal that identifies the flight. Perhaps the beginning of a malfunction in the electronics and engineering compartment?

9. At 1:37, the automatic ACARS transmission does not give its 30-minute report. Had the problem become a full-blown emergency?

10. An undocumented report that a Narita, Japan-bound flight is asked by Ho Chi Minh Center to attempt contact with Malaysia 370. The Narita flight is approximately 30 minutes ahead but is unable to establish contact with Malaysia 370. This attempted "relay" would have been a typical procedure used by air-traffic control. Ho Chi Minh Center would have first attempted contact on the assigned frequency and then used the emergency frequency that all controllers and airlines monitor. There is cause for concern but no reason just yet to sound the alarm.

11. At 2:15, Malaysian military radar (disclosed one week after the disappearance) claims to have observed a primary target on the west side of the Malaysian peninsula, indicating that the flight flew a westerly course at some point after the last verbal transmission.

In my view, the above timeline only includes what appears to be the most credible assertions. Subsequent to this timeline, reports of satellite "pings" and engine data being transmitted indicate that the airplane may have remained airborne for an additional five to seven hours. Without verification and true understanding regarding the implications of these reports, it is difficult to speculate. In addition, raw data from another radar site indicated that the 777 may have climbed to an altitude above the airplane's certified ceiling and then quickly descended and climbed again. And now the most recent assertion has the airplane descending to 12,000 feet. If in fact the airplane descended to 12,000 feet, its fuel consumption would have been almost double that at the higher altitudes. In that regard, how did the airplane fly so far south into the Indian Ocean, as has now been announced emphatically by the Malaysian Prime Minister?

Assuming the airplane did indeed continue to fly, here is a hypothetical scenario:
A smoldering fire began to affect the components in the electronics and engineering compartment. The fire was insidious, producing smoke at a slowly increasing rate. As components began to fail, the crew followed appropriate checklists until it was determined that the primary concern was to land the airplane. The captain entered the waypoint identifier for a diversionary airport into the flight management computer. The autopilot turned the airplane toward the diversionary airport, a southwesterly direction.
In the meantime, the crew attempted to control an airplane that may have been losing portions of its electronic flight control systems. Primary flight displays on the instrument panel may have begun to shut down, making it difficult to interpret airplane attitude and airspeed. The crew donned their oxygen masks with the integral goggles, but toxic fumes, low visibility etc. eventually overcame them when the oxygen bottled was depleted due to the pilots both breathing rapidly in a high-stress environment and the mask switch most likely being selected to 100% at high pressure.

A degraded autopilot continued to steer the airplane toward the diversion airport at an altitude selected by the crew. When the airplane reached the last waypoint -- the diversionary airport -- the flight management computer functioned as designed and kept the airplane on its last heading. Fuel exhaustion caused the engines to flame out one at a time. Operating on one engine for a brief period may have caused a turn due to the differential power that couldn't be compensated by a degraded automatic system.
When the autopilot could no longer maintain the airplane at the selected altitude, it disconnected. The airplane would have begun a slow, erratic descent. When the last engine shut down, the ram air turbine would have deployed, providing both limited hydraulic power and limited electric power. Eventually, the airplane would have descended and crashed into the ocean.

A lot of focus has been on the fact that the crew did not communicate the problem. Maybe they did attempt to declare a "mayday." Had the primary radios been destroyed by fire? Or more likely, the communication went unheard because the airspace where the malfunction occurred was just out of the range of normal VHF communications, in addition to being just outside Ho Chi Minh Center's radar.
It is all pure speculation until the airplane is located. I'd like to keep an open mind. Regardless, perhaps I've explained some of the unexplainable.

Author's note: Les Abend is a 777 captain for a major airline with 29 years of flying experience. He is a senior contributor to Flying magazine, a worldwide publication in print for more than 75 years.


Pray for the passengers of flight MH370

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