From Page 27 of the report:
The 1825 and 2419 Arcs: Log On Requests
The 1825 and 0019 SATCOM handshakes were log-on requests initiated by the aircraft. A log-on request in the middle of a flight is not common and can occur for only a few reasons. These include a power interruption to the aircraft satellite data unit (SDU), a software failure, loss of critical systems providing input to the SDU or a loss of the link due to aircraft attitude.
An analysis was performed which determined that the characteristics and timing of the logon requests were best matched as resulting from power interruption to the SDU.
18:25 Log On Request took place shortly after its last radar reading at 18:22 and just before its 18:29 turn south. He may have inadvertently hit the wrong switch preparing for the turn south or hit it deliberately to cut power to disguise his turn south.
Then there is this:
18:39 — Unanswered ground to air telephone call #1 at 18:39 shortly after it would have come off autopilot at 18:29 for its turn south.
23:14 — Unanswered ground to air telephone call #2 at 23:13 shortly after it would have then come off autopilot again this time at 22:41 for its turn east.
Coincidence????
So let’s plug it all in to the timeline:
16:41 KLA N2.73E101.71 to points of turnaround IGARI [17:19] then to N7E103.5 [17:21] totalling 325 miles.
17:21 N7E103.5 on heading west
N5.3E100.3 250 miles Penang Island where it turns NW.
18:22 N6.6E96.3 289 miles NW of Penang Island. 539 miles covered by that point averaging 530mph.
18:25 — Log On Request
18:29 N6.85E95.45 [Turning Point] 61 miles @530mph.
18:39 Unanswered ground to air telephone call #1.
19:41 S2E93 634 miles @528mph
20:41 S9.75E92.5 536 miles @536mph
21:41 S17.5E92 536 miles @536mph
22:41 S25.25E91.5 536 miles @536mph [autopilot had to have been disengaged about here to slow the speed and/or change course eastward to the rising sun]
23:14 Unanswered ground to air telephone call #2.
24:11 S36E90.5 745 miles @496mph [same line slower speed]. Total to this point 3895 miles.
24:11 S30E97.5 527 miles @351mph [eastward and slower speed to search area]. Total to this point 3677 miles.
24:11 S27.5E100 583 miles @389mph [eastward and slower speed to search area]. Total to this point 3733 miles.
24:19 — Log On Request