tl;dr: MH370's radio communications

NB 23 January 2022: When I first wrote this post in March of 2015, I intended it to be a tl;dr version of "What really happened to MH370?", geared more towards pilots and other aviation geeks. FWIW I worked in aerospace and I was a flight instructor for many years. As with the companion article I've updated this post to fix formatting issues and to repair broken links. Given the perspective of time, I do want to write a follow-on article about MH370 and MH17, and eventually I will. There are things that I got right and things that I got wrong, but I'm gonna stick with my basic thesis, presented here, that MH370's radio communications offer subtle clues about what happened all those years ago. I'd be happy to hear from any pilots or aviation geeks who'd like to offer up their opinions. May the souls of MH17 and MH370 rest in peace.

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Let's start with the final exchange between ATC and MH370 (the transcript uses the ICAO designation for Malaysian Airlines, “MAS.” “MH” is the designation used by the IATA): 

01:19:24 ATC Malaysian Three Seven Zero contact Ho Chi Minh 120 decimal 9 Good Night 

01:19:29 MAS370 Good Night Malaysian Three Seven Zero 

The crew’s final response marks the only time during the flight that they failed to completely read back a controller’s instructions. For example, shortly after takeoff, the Kuala Lumpur tower instructed MH370 to contact departure control: 

12:42:52 ATC Malaysian Three Seven Zero contact Lumpur Radar One Three Two Six good night

MAS 370 Night One Three Two Six Malaysian Three Seven Zero 

In this case the crew properly acknowledged the directive to contact departure control on a frequency of 132.6 MHz by reading back the frequency along with their flight’s call sign. 

There is another slight oddity in the transcript involving communications about altitudes. After takeoff, Kuala Lumpur departure control issued two altitude assignments to MH370. The first was a directive to climb to “flight level two five zero”: 

12:46:51 ATC Malaysian Three Seven Zero Lumpur radar Good Morning climb flight level two five zero 

12:46:54 MAS370 Morning level two five zero Malaysian Three Seven Zero 

Note that the crew’s response properly included a read-back of the altitude assignment along with the flight’s call sign. A few minutes later, departure control directed the flight to climb to its desired cruising altitude of FL350: 

12:50:06 ATC Malaysian Three Seven Zero climb flight level three five zero
12:50:09 MAS370 Flight level three five zero Malaysian Three Seven Zero

Once again, the crew's read-back of instructions from ATC followed standard procedure. Eleven minutes later, MH370 reached its assigned cruising altitude, and the crew reported that fact: 

01:01:14 MAS370 Malaysian Three Seven Zero maintaining level three five zero
01:01:19 ATC Malaysian Three Seven Zero 

The slightly odd nature of that transmission is that it was superfluous. The ATC directive didn't include the phrase, “report reaching”, but the pilots chose to report it anyway. That fact in itself isn't so very odd, but what happened six minutes later is. The crew repeated their verification that they had reached FL350, in spite of the fact that the controller acknowledged their earlier, already-unnecessary report:

01:07:55 MAS370 Malaysian...Three Seven Zero maintaining level three five zero
01:08:00 ATC Malaysian Three Seven Zero 

Both communications may be innocuous, but given what happened to MH370, they merit extra scrutiny. Why would the crew repeatedly transmit unnecessary altitude information? One possible explanation is that they were soliciting an early hand-off from Malaysian to Vietnamese air traffic control. If there were no other aircraft in the area, the Malaysian departure controller could conceivably have been prodded into an early hand-off to the next area controller in Ho Chi Minh City. In any event, the final transmission between MH370 and Kuala Lumpur occurred eleven minutes later, during which the crew failed to read back the frequency assignment during hand-off to Ho Chi Minh City. It may be nitpicking, but the final transmissions from the cockpit of Flight MH370 do appear to have a deliberate component – And that is that they were designed to sow the seeds of confusion. 

The oddities in MH370’s final radio transmissions support the theory that someone in the cockpit wanted the flight to disappear, and that they chose the moment of the hand-off to initiate an intentional evasion. Less than two minutes after someone uttered the words, “Good Night Malaysian Three Seven Zero,” MH370’s transponder as well as its ADS-B, were turned off. At about the same time, the aircraft turned sharply west across the Malaysian Peninsula and headed towards the Bay of Bengal. I'm very curious to know if other pilots find the frequency omission and the superfluous altitude reports to be at all odd... 

Known flight path of MH370. From the Wikipedia article about its disappearance. No licensing terms specified by the author:
https://en.wikipedia.org/wiki/Malaysia_Airlines_Flight_370#/media/File:MH370_flight_path_with_English_labels.png

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