MalaysiaAir MH370 Response To Some Reader Questions…

We’ve seen a number of questions from readers prompted by the abundance of theories on what happened to MH370 so it may be productive to share some ideas with you all. The purpose is to help you understand the complexity of the search. It is an enormous undertaking. You can find our initial hypothesis here. We also continue to pray for the families that are suffering, struggling to cope with this enormous tragedy.

  1. First is the concern of the aircraft behavior as it runs out of fuel?
    1. To begin with, fuel, even in light aircraft, is not consumed evenly from all tanks, so it’s his highly unlikely the engines would have stopped working at precisely the same moment in time. In this situation, a pilot is put in a position where he or she must determine if there is enough fuel to fly the aircraft to the nearest landing field on a single engine. Consideration of runway length and condition goes out the window in this scenario and lading the aircraft is paramount. If the pilot is over water and too far from land, the pilot  is thinking about a water landing. He or she would use all available power to gain as much altitude as possible to setup a glide, while transmitting a May Day and position data.
    2. To execute a glide, the pilot establishes an attitude, depending on aircraft weight and other parameters, to maximize the amount of over ground travel.  The greater the altitude the longer the flight time and the further the aircraft would travel. Weight and balance are play an important role in this situation. It means setting up a descent at an appropriate airspeed. The pilot would allow the nose to drop to maintain a desired airspeed. At this speed, the wing still generates a sufficient amount of lift to keep the aircraft flying and all the control surfaces, like the ailerons, would provide control for a controlled decent and ultimately a water landing.
    3. If the aircraft makes a successful water landing, meaning little or no structural damage, there is enough time to open the emergency exits, deploy the slides and commence evacuation of the passengers.
    4. If on the other hand, the aircraft suffered structural damage there is a high degree of probability the aircraft would begin to flood. In heavy seas, that flooding would occur quickly and with sufficient force to prevent evacuation of the aircraft. It would sink impacting (note: not settling) on the ocean floor. In MH370’s case that’s anywhere from 10,000 feet to 14,000 feet depending on location.
  2. Why are there no crash signals being transmitted?
    1. The EPIRBs, of which there are several, and the ELTs transmit on UHF and VHF  frequencies at 400Mhz and 121.5 MHz (monitored and reserved for emergency comms). These are line-of-sight frequencies, so if the aircraft is below the water, and the EPIRBs were not released but still trapped in the aircraft, UHF and VHF frequencies would be so attenuated as to make them undetectable assuming the transmitters are able to work submerged. Even at LF and VFL (low frequencies or very low frequencies), depending on the depth of the aircraft, and at what depth these devices became active, a distress signal may escape detection; leaving only the acoustic ping of the flight and voice recorders operational.
    2. Those of you that have SCUBA experience know that as you go deeper, water pressure compresses your body and you become less buoyant. Even equipment that would normally float, like seat cushions may not make it to the surface for quite some time. The same is true for EPIRBs. A situation that is sadly true for the victims; many of whom are still secured by seatbelts.
  3. What efforts are currently underway?
    1. Very capable and professional assets are presently engaged in the search. Searchers are employing satellite imaging, visual and radar surveillance, passive and possibly active sonar. As sensitive as military passive sonars are, the flight recorder’s acoustic pings have a limited range and are hampered by thermoclines. A thermocline is a density and temperature differential that attenuates or masks submerged acoustic signatures. Thermoclines are often used by submarines to disguise their presence from surface ships and aircraft. Therefore, to have an effective and comprehensive search submarines are also being used. Active SONAR emits a variety of acoustic frequencies that bounce back to aid in detecting objects. A strong echo would suggest the presence of an object perhaps leading to determining a location of the wreckage.
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