"Possible turn" at about 18:25?
 

18:22 Last primary radar contact, aircraft heading NW
18:25 Log-on request initiated from the aircraft terminal
18:28 First 'handshake' arc, BTO and BFO indicate aircraft heading south

Between 18:25 and 18:28 there were 4 exchanges between the ground terminal and the aircraft terminal. The recorded BTO and BFO values for those exchanges varied considerably, which may be attributed to either the non-stabilized operation of the aircraft terminal or the turning of the aircraft. After 18:28 the BTO and BFO values consistently indicate a southern heading, so there must have been a turn after the last radar contact. Between the first and the sixth arc the BTO and BFO values show a steady progression, then there is another 'jump' to the final arc. The final arc is from a log-on request initiated from the aircraft, probably after a power interruption.

EDIT:
The 'jump' between the sixth and the seventh arc may have been due to the airplane descending at the time of the seventh arc.

Katherine states on page 6 of her thread that:


'The GPS time updates automatically. At no stage did we move beyond Thailand time. I don't know when it switched to Thailand time.'

The GPS track of the yacht was exported almost 3 months after being recorded (when the skipper wrote up the journey for a blog). The track would have been recorded in UTC but the skipper exported it in local time of the location where he wrote the blog. I think he was only interested in the track for the purposes of plotting a map and at the time didn't care about timestamps.

He doesn't seem to be talking online about the incident (in my view probably quite wise) and his wife is so bad at communicating facts that probably only a forensic analysis of the recorded data files would reveal the truth.

But in any case what's the point? She only filed a report after armchair experts elsewhere noticed that the yacht had been close to the estimated aircraft track. Up until then she hadn't connected the two events. It was dawn, she saw strange colours and that time of day always creates unusual lighting effects in the sky).

Had she kept a diary and filed a report sooner it may have helped the ATSB with it's construction of an estimated flight path. As it is her story, even if true, adds absolutely nothing to the investigation.

exeng
 

From FL350, you'll travel about 85nm. At Vmd (ca 240kt IAS), you'll set off at about 410kt TAS. By FL150, your TAS will have dropped to about 300kt. For tha complete descent your average TAS will decrease from about 7nm per min at TOD, down to 4 nm per min as you reach the Indian Ocean.

You'll do those 85 miles in about 15 mins.

At Vmd.

That is based on a lot of assumptions. Such as a pilot controlling the aircraft descent. Several thousand posts back someone reported testing an uncontrolled engine off descent in the SIM and reported a series of phugoids rather than a controlled descent. If a pilot is assumed then perhaps a dive maintaining speed to provide some controllablility at low level for a minimum wreckage ditching.
Or to put it another way, we are dealing with SWAG, anywhere within maximum glide range of the last 'Ping' position could be the ocean entry point. It could even be under the last ping if 'the pilot' had spiralled down

Ian W
 

I agree. The original discussion centred on how long it would take to glide from FL350 to sea level. Anything other than a controlled descent at or about Vmd would take less time.

I should have said 'not more than' 15 mins or 85nm or so.

Ian W,

Just to be pedantic, and while there is not much else to discuss -

In a phugoid the airplane maintains an approximately constant AoA, i.e. constant L/D. While it is cyclically exchanging potential and kinetic energy, it does not lose total energy more rapidly than in a constant-speed descent, so the total range and time would not be affected.

Maybe that's the case with the engines failed producing no thrust at all but only drag, but on idle thrust the time to glide from FL350 to sea level would exceed 20 minutes at Vmd at low weights (I know, low weight doesn't really influence gliding distance significantly but it doest influence gliding time).

If it really was an intentional glide I see no reason why the glide would have been conducted with engines failed due to fuel starvation rather than very low fuel remaining.

exosphere:


Just another "what if."

Looks Can Deceive.
 

With reference to the woman who may have seen the flight from a boat. I've been around aircraft all my life, but back in the 1990's, an odd incident occurred which illustrates a point;-
One summers afternoon, a friend rushed into my house to tell me to 'come and see the plane on fire'. Hastily going outside, my perception was of a light-aircraft at perhaps 500 - 800' agl coming towards me soundlessly. I could see the flames licking around the fuselage. However, after perhaps 15 secs, I realised that something was very wrong with my perception. There was still no sound, and the a/c wasn't any closer.... I then realised that the a/c was MUCH further away and very high. Later, radio and TV reports told of people about 70m away reporting it as 'overhead.....so it was very high. Many thousands of people saw it. (ATC at Birmingham reported no plot. There was much speculation, UFO, SR71, Aurora, you name it, not that it's relevant here.)
What was so amazing was how convincing the a/c was at looking much MUCH closer. It had something to do with the speed of the movement of the flames.
Whilst I'm not supporting her report directly, I am saying that, in clear air, flames, even at a great distance can look MUCH closer. My point is that a seasoned observer can be deceived, then it may explain a 'lay' witness not describing that which we 'expect' them to see, as I can attest.

Does anyone know why the USN pinger locator system doesn't use an array of transducers to determine the bearing to the back box acoustic pinger? There are many commercially available systems which use transponders to measure range and bearing to determine positions of underwater targets like ROV's. You can't get range from a free running pinger but you can get bearing. An example Ultra Short Base Line (USBL) system is covered in the link below.

USBL - All Systems

From the description.

"The second is that the bearing can be determined by knowing the discreet difference in phase between the reception of the signal at the multiple transducers present in the transceiver. This allows the USBL system to determine a time-phase difference for each transducer and therefore calculate the angle of the arriving signal."

All you would need is a compass on the fish along with the derived angle to get the bearing. This would allow the pinger to be found MUCH faster. Using a single transducer seems to be very inefficient.

3 million reward offered by families.
 

$3 million reward offered by families for whistleblower to come forward with information regarding missing flight MH370.
https://uk.news.yahoo.com/malaysia-a...3.html#CnWhrz1

Kiwi loses job after MH370 email | Stuff.co.nz

NZ oil rig worker who reported seeing burning aircraft, Mike McKay, was sacked for his trouble.

I don't believe he or British sailor Katherine Tee saw MH370 burning, but I would like to see some explanation for this phenomenon.

Tarko1

would that be the angle in 2D or 3D. ie bearing or bearing and elevation,and what about all these weird underwater effects we are told about

the article actually says:

So we was about to head home anyway, but got a 5 day early mark, and was paid for the 5 days.

Question... At 250 knots glide speed ( no power) on a 777 what would be the approx sink rate? 30 fps?

oldoberon

Normally, it would be the horizontal angle or 2D. The horizontal angle would not be affected too much unless you were tracking a reflection in which case, the angle would be to the reflection point. You could get a 3D solution by having more transducers vertically separated. I would guess the 3D would be affected more by the underwater effects but would still be useful.

The horizontal angle would the get pinger location down to a few meters.

Kiwi loses job after MH370 email | Stuff.co.nz Sounds like a reliable chap, worked there for 35 years and sent home early complaining contracts mean nothing. But he didn't get the sack. Nudge nudge wink wink.

Relative to the errors in estimating distance:

I have observed six Space Shuttle launches from my community, Albany, GA, USA which is about 350 miles from the flight path as the Solid Rocket Boosters were completing their burn. If I had not known better I would have said they were ten or fifteen miles away and the flickering flames were a thousand feet long. In reality, they subtended about three degrees of arc, which made them close to 20 miles long.

Regarding flames, Katherine Tee said she didn't see any as such. (Page 12, CruisersForum)


'And no, I didn't see any flickering that looked like flames. Just an orange glowing thing that I thought was a plane with orange lights.'