Independent Group member Bill Holland appears to have sorted out the head-scratcher concerning the location of the QZ8501 tail section. His explanation jibes with where we’d expect the plane’s fuselage to wind up, given the fact that just before it disappeared from radar it was descending with alarming speed. I’m pasting here Bill’s recent email in toto:
I think I have the tail GPS coordinates figured out…
I kept finding references to the tail being found that translate as:
The mapping experts who are in MGS Ship Geo Survey finds it precisely in the coordinate 03.3839S (South latitude) and 109.4343E (East Longitude).But, I searched and found a version that seems to make more sense:
Aga pun menyampaikan titik koordinatnya, yakni: Latitude 3;38;39S, Longitude 109;43;43 E.
…in English:
Aga also convey the point coordinates, namely: Latitude 3; 38; 39s, Longitude 109; 43; 43 E.The numbers being quoted are correct, … Only the punctuation was wrong!
-03° 38′ 39″ 109° 43′ 43″ (degrees minutes seconds)
This is about 2.5nm South East of the last SSR/ADS-B location (Google Maps measures 3.03 statute miles = 2.63nm)In my screen grab [above]:
– the lower yellow start marke the tail section (and the blue annotation is the distance from the purple star)
– the purple circle is the last lat/lon from the SSR (ADS-B),
– the purple star is the approx location from the primary radar image.
– The red box is supposed to be “Most Probable Area 2”,
– the black tilted rectangular outline is the left (Western) section of the “Underwater Search Area”.
– The yellow diagonal line is Route M635 between TAVIP to RAFIS.
– The black diagonal line is the FR24 estimated flight path (the inverted teardrops are individual extrapolations from FR24 after the last valid ADS-B data data they received)[ignore the white square, the blue square, the Northern yellow star, and the green diagonal line]
-Bill
Really, it’s remarkable that searchers didn’t scour this location right away, and instead spent a week searching far down-current. There appears to have been some confusion between the nature of floating debris, which disperses as it’s carried by currents, and debris on the seabed, which will tend to remain where it falls, more or less directly under the point where it impacts the water.
The latest news is that preparations are underway to raise the tail section and hoist it onto a ship. Hopefully, the black boxes will be found within, and the cause of the accident one step closer to being revealed.
@Oleksandr,
That one Trent 892 table I posted is all I have. There are no other notes on that page beyond what you see.
The altitude flown was steady at 35,000 feet from 17:01 to 17:19 per the ADS-B data. There is only scant, indirect evidence on the altitude flown after diversion, and arguments can be made both for and against 9M-MRO maintaining a high altitude. No one knows for sure, so without direct and reliable evidence to the contrary, many people have assumed the altitude did not change drastically. This issue is really only slightly significant, and that is due primarily to the extent that it affects the fuel burn during this period. The average air speed from 17:19 to 18:22 was ~Mach 0.84, and if there was a significant descent during this period while maintaining such high speed, I would expect the endurance to be measurably reduced. So, for me, the primary evidence against a significant descent from 17:19 to 18:22 is that either the average airspeed would be noticeably reduced or the endurance would be measurably shorter. Since I don’t see either of these effects in the data, I think it is more likely that 9M-MRO stayed at a high (but not necessarily constant) altitude during this period.
Yes, I have stated before that the curvy track until 9M-MRO was past Penang indicates to me that it was being manually flown until then. I don’t think they necessarily entered a highly complex route after then. IMO the minimum number of waypoints needed after 18:00 is three: (1) MEKAR or ANOKO entered ~18:00, (2) a waypoint to the north that was effected very shortly after 18:25 (to explain the 18:27 BFO and the 18:28 BTO data), followed immediately by (3) a turn to a waypoint heading southward.
If the cabin and flight deck were filled with toxic smoke, this would quickly incapacitate the passengers and most of the flight attendants. The drop-down oxygen masks only supply oxygen for about 8 minutes, and they are not designed to keep out smoke. The flight crew had full face masks with a longer-lasting oxygen supply. Perhaps even those ran out shortly after 18:30 (~1 hour 10 minutes). I will note that descending to low altitude wouldn’t do anything immediately beneficial to eliminate smoke inside the aircraft. The flight crew might have been more concerned with stopping the fire producing the smoke than in descending immediately (here I assume there was no depressurization). Perhaps they even turned off some equipment in the hope they could control an electrical fire and slow the smoke generation. Still, it’s a good question to ask why they did not land at the first airport they came to (Kota Bharu). Also, why did they continue on to Penang flying manually.
IMO the waypoints may have been entered (after Penang) singularly as certain decisions were made at three different times. I don’t think it is a coincidence that at least one and probably two turns were made in the immediate aftermath of the restoration of power to the SDU (and likely to other equipment as well) at ~18:23.
IMO the “final” turn could be a desperate attempt to land (at Banda Aceh, Maimun Saleh, or even possibly Car Nicobar), and the SIO route was an unintended consequence of incapacitation shortly thereafter.
@Matty-Perth,
Off the top of my head, the governments who have contributed significant resources (aircraft and ships) to the search for MH370 are Malaysia, China, Australia, and the United States. Perhaps there were others involved in the early days of the search.
The stated reason for the 4th ship is to look (with a sonar on an AUV) at areas that the towed sonars are not able to image adequately. Therefore it does not appear at this time that it will have a significant effect on the timeline for the towed sonars to complete the current search area. Its purpose seems to be to fill in a few difficult areas and make sure nothing is missed.
@felinenut.
I found your publication and will be reading it.
I never believed it ended in the SIO
But it’s time for my Maine Coon.
@ Myron
What? How did you know I have 2 Maine Coons outta my now 11 cats?/ LOL
@Gysbreght,
Perhaps it’s the titles of the ATSB’s Figures 2 and 3 that are causing the confusion. One says: “Figure 2: MRC boundary based on turn near the 1st arc – 1828”, and the other says “Figure 3: MRC boundary based on turn at time of telephone call – 1840.” I was interpreting the purple areas as the “MRC boundary” for the turn at the time listed in the title. I can see your point that it may only be the routes drawn in the figure that correspond to the stated turn time and not the purple areas (which may instead encompass all turn times between 18:28 and 18:40). That would explain why the purple areas don’t change between Figure 2 and Figure 3. It’s a sloppy presentation.
I would quibble that speeds are not given by the ATSB, but that is not really important. What is potentially important is that they assumed constant true air speed instead of a constant Mach number or Long Range Cruise. That will reduce the performance limit below what is possible with more efficient speed profiles.
Here is a scenario that explains my view of the LNAV situation:
At 17:19 9M-MRO is on AP going from IGARI to BITOD.
At 17:22 the plane is diverted, makes two left turns, and heads toward Kota Bharu under manual lateral navigation.
The plane continues past Kota Bharu and makes a wide turn south of Penang while being flown manually.
At ~18:00 the AP is engaged to head toward MEKAR (or perhaps ANOKO). All lateral navigation after this point is via waypoints using the FMS.
At ~18:25 the plane turns north to an unidentified waypoint.
At~18:28 the plane turns toward the south (through the west) to an airport (Banda Aceh or Maimun Saleh).
Before reaching the airport, the flight crew is incapacitated at ~18:30.
The AP continues south, after passing the last entered waypoint, until fuel exhaustion.
My response to Oleksandr from earlier today is also on this subject.
Thanks Dr Ulich – but I was more referring to the underwater search and not the initial one. Australia are paying for the seabed search, is any govt interested in doing another one? It might be good PR at home for the Chinese, but it might also be a token effort in some alternate place if we get one at all.
All: I would be careful about drawing conclusions about whether or not the plane was hand flown between IGARI and PENANG based on a curvy path. The only data we have about the path is what was supplied as Figure 2 of the June 26 ATSB report. There is significant scatter in the primary radar data that could produce curvy paths depending on how the radar blips are translated to a continuous curve. Also, in Figure 2, it appears that the plane was flying an overall straight course after PENANG to MEKAR. However, the military radar plot from the Lido Hotel meeting in Beijing on March 21 shows the plane shifted direction upon intercepting VAMPI and flew on airway N571 towards MEKAR.
The bottom line is I believe it is unwise to put much faith in the details of the path shown in Figure 2 of the ATSB report. In my mind, the figure should not be used as evidence that the plane was not in autopilot over the Malay peninsula.
If only we had the raw radar data, we could make more sense of this. But alas…
Victor
@ Myron…
here some kinfo graphics.. https://memarciniak.wordpress.com/2015/01/04/mh370-sar2-data-from-qz8501-showed-the-way/
If you need some info on the on infographics
You can ask here, but it’s likely twiiter will find me faster…
Dont hestitate to ask, cuz there is a lot of
crap that has to detailed to write a full report since the more crap that is published and misunderstood all has to be explained…
Yes… there is alot to clean up from the 10 months of crazyiness
;-)>
@ felinenut
@felinenut
-once a MC U know-
[@FelineNut, You are BANNED for being incomprehensible, rude, misinformed, delusional, and, let’s face it, probably drunk.]
Bobby,
Thanks for the table and comments.
With regard to the AP scenario (I do not discard other scenarios) I am almost on the same page as you.
I hardly believe in a smog scenario because of a number of reasons (you mentioned one of them). And you forgot about SDU: if it came back due to human intervention, this would mean somebody was alive onboard by 18:25. Why wouldn’t they make a call to report emergency as a first thing upon link restoration? Also you forgot about a minor turn at MEKAR (if is not an error of merging data), meaning that VAMPI was also entered, and it took place before 18:25. The heading of 180 deg would mean at least one more waypoint had to be entered after IGOGU or ANOKO, or some other northern point has to be ‘inserted’ after MEKAR. But so far I did not find any reasonable sequence of waypoints to approach either of the 3 mentioned runways, with the condition for the last two points to be at the same longitude. On top of it, if one considers a landing attempt, it would be logical to consider descent starting shortly after 18:25, right? In either case, if landing was intended then FMT would occur much later than 18:40.
@VictorI,
You may be right about the “curvy” paths plotted by the ATSB. If AP with waypoints was actually used, the one at Kota Bharu is probably GOLUD. I never could find one near VPG that matched the plot. The very wide turn shown there by the ATSB does not seem consistent to me with AP, assuming it is correct. Perhaps they approached Penang on AP, flew a wide turn to the south manually, and then went back on AP again. before reaching Palau Perak.
Flitzer_Flyer,
Regarding HEADING and TRACK modes, yes, some have suggested that the true/magnetic switch only controls the display whereas the actual heading or track is always true. I have not found a definitive, unambiguous statement in any documentation anywhere to either affirm or refute that conjecture. However, after a bit of research I am quite sure the switch does control the mode. The first evidence comes from reading various aviation boards, where it is emphasized that at a minimum, a pilot should always have a compass, a pitot tube, and an altimeter, so it is alway possible to fly a magnetic hold route. The second piece of evidence comes from reading about Korean Air Flight 007 – the Boeing 747 shot down over Russia. The Wikipedia page gives a detailed analysis of what happened, and says that “the aircraft had flown on a constant magnetic heading instead of activating the INS” (the latter apparently being the equivalent of LNAV mode on a 777.) An examination of the flight path map confirms this analysis – the true heading varies from about 260 degrees near Anchorage to 230 degrees over Sakhalin Island, which agrees in both sign and magnitude with the change in magnetic declination (+20 to -10 degrees) over that path. The constant magnetic heading would be about 240 degrees.
It would be most odd if a 777 could not fly a type of route that every other type aircraft (with which the 777 shares the skies) can.
Victor,
Re: “However, the military radar plot from the Lido Hotel meeting in Beijing on March 21 shows the plane shifted direction upon intercepting VAMPI and flew on airway N571 towards MEKAR”.
This is an example of selectively discarded ‘fact’ in favor of other ‘facts’, I criticized earlier.
– It did not fly on the airway N571. It flew along only one section of N571, between the two closest waypoints. I have headache to understand why this is sufficient to state MH370 flew along N571.
– It did not fly strictly via VAMPI and MEKAR. Close, but not exactly.
– If the minor turn is an artifact of the merging data from different sources, as I recently suspect, there is no evidence of following waypoints at all, not talking about N571. This, btw, can explain why ATSB has no change in the direction in their report: they simply used a correct transformation in ArcMAP. And this explains the initial mess.
– If you have doubts about horizontal accuracy prior to Penang, and discard altitude variations as white noise at all, why do you trust the data after Penang?
Oleksandr: You said, “This is an example of selectively discarded ‘fact’ in favor of other ‘facts’, I criticized earlier.”
Have you just realized that all the evidence is not completely consistent? I freely admit that I select some evidence over other evidence to build a scenario. You are being naïve if you believe you are not doing the same. The difference I admit it and you do not.
You said, “It did not fly on the airway N571. It flew along only one section of N571, between the two closest waypoints. I have headache to understand why this is sufficient to state MH370 flew along N571.”
I’m not going to battle you over semantics. The plane seems to have been flown over part of N571. It also seems to have changed direction at MEKAR along N571 as the BFO at 18:28 suggests an azimuth of around 297 deg.
If my statement about flying along N571 gives you a headache, take an aspirin and get better, and stop the melodrama.
You said, “This, btw, can explain why ATSB has no change in the direction in their report: they simply used a correct transformation in ArcMAP. And this explains the initial mess.”
The IG was informed that the radar data shown in the report was the only data the ATSB received from Malaysia. The ATSB was not even aware of the Lido Hotel radar image. The fact that the path was rendered by Malaysia should make you second guess the details of the path shown in the figure. Malaysia data has been consistently inaccurate in the details of the data it has shared.
You said, “If you have doubts about horizontal accuracy prior to Penang, and discard altitude variations as white noise at all, why do you trust the data after Penang?”
I said I don’t trust the details (such as the curviness) of the radar path shown in Figure 2. I do trust the trend of the path, and I also do trust the radar blips shown in the radar image (even if some of the text added by Malaysia was inaccurate). As for altitude variations, Malaysia itself has dismissed the validity of that data. On top of that, the distance and time interval of the radar path suggests a plane flying at cruise speeds, and therefore at cruise altitudes. Substantial changes in altitude would have lowered the average speed and burned more fuel.
Just a thought….
The Cpt. was born in 07-31-61 and was 52 years of age when he disappeared….
MEKAR – NILAM – IGOGU – ISBIX – 31°7’52″S, 90°00’0″E
Maybe, when the Cpt. did it, it might be thinkable that he entered his own birthdata into the FMS as his last waypoint ~ 450 mi before MH370 chrashed along the 7th arc.
On this route, MH370 might be really close to the IG-Impact-Location.
Just a thought
@LouVilla – I initially laughed when I read your post.
However, if the plane was sent to a random location, there’s a remote possibility it wasn’t really random, for the same reason people use their birthdays as PIN numbers.
It’s a long shot, but not impossible.
However, I’d suggest not birthdays but round numbers. Just like people tried to fit waypoints into their models, rounded values for heading and lat/long should also be tested because there should be at least some bias towards round numbers when data is keyed in. For somebody wishing to lose a plane in that part of the SIO, I highly doubt they’d even bother to enter a decimal, either with heading or lat/long.
A path that intersects or continues to a point Y.00000 lat and X.00000 long would be very curious. (I don’t know whether coords are entered D/M/S or decimal, but it doesn’t really matter.)
In fact, I’d even go a step further: if a path can’t be related back to SOME magic number or published coordinate (such as a waypoint), you can pretty much rule out human input.
@sk999: There was a lengthy discussion on this issue around 19 Dec, so I’m not going to start going around the complete loop again.
Try these references
Honeywell B777 FMS Pilot’s Guide.
“Only the active waypoint course can be referenced to magnetic north because the ADIRU can provide magnetic variation only for present position. All subsequent waypoint courses are displayed as true
courses.”
“COURSE/HEADING
The computed course information is displayed in 1L through 5L between the waypoint identifiers. The current desired course on the ACT ALTN NAV LEGS page is relative to magnetic north (designated
byM). Computed course for other than active waypoint is relative to true north (designated by T). The CDU uses the same manual/automatic MAG/TRUE selection as the FMC.
And from the Digital Avionics Handbook, discussing Lateral Guidance – –
– – -“the course information is generally displayed as magnetic courses – – -. This historical-based standard requires the installation of a worldwide magnetic variation model in the FMS since most of the internal computations are performed in a true course reference frame. Conversion to magnetic is typically performed just prior to crew presentation.”
@JS – When you suggest round numbers don´t be surprised when IGOGU – 31°7’52″S, 90°00’0″E is equal on heading 186° going south.
Operations manual, section 10:10:30
Heading Reference (HDG REF) Switch
Pushing alternately selects the heading reference for the PFDs, NDs, AFDS, and
FMCs.
There are also multiple instructions like this:
If the airplane is operating in polar regions:
HEADING REFERENCE switch ……………………………………..TRUE
@all
Hi, Im not paying attention here too much, but reading all the discussions about FMT and reviewing the raw log again (plus Dr. Ulich trial #17 sheet now), I still can’t refuse to think about what I got as subgame occams razor when I saw the log first time – exactly two weird in-flight 0x10 log-on responses from plane and the gap in requests between 17:07 and 18:03 in log. Why there are not more unansvered requests?? When exactly engines stopped to respond? My idea was that they might climb (in spiral or so) here to gain energy and then GLIDE with engines-off (is this possible??) to mask north/south direction without any trackable response. Then since 18:25 with engines-on fly as quickly as possible somewhere to north arc and then just before approach/descent glide since 00:11, and then land with engines-on after 00:19:29, with final response at 00:19:37, where BFO (so in fact speed) is near to zero (although, read somewhere that first BFO/BTO values just after logon arent reliable at all). I simply dream that at this time the plane is not moving and is landed somewhere… I know that such plane can glide up to 200km or so, there was such cases in history, but I dont know if this is possible scenarion regarding the ACARS logons and lack of responses. Most crucial though is why the log has no more REQUESTS to plane after 17:07 … weird 🙁
Can somebody tell something about possibility to glide?? Or its nonsese??
and BTW, as Jeff noted, Indonesian military radars may really know far more
Another question: have pilots access to RX requests which we see in logs? Can they expect when there will be silence to fly without responses? Or is some extra handheld device able to show this in real-time?
@Bobby, Gysbreght:
The probability that Figs.2/3 purple area is the “stretched” 18:28-18:40 feasibility zone is 0.
Proof: Fig.3 18:40 paths CONTAIN this zone all by itself. It is the 18:40 zone.
It is made to LOOK like it accommodates an 18:28 FMT in Fig.2, via careful excision of all 18:28 path(-segment)s which would otherwise have stretched it properly to the west.
Confusing? Definitely. Sloppy? Not in my book.
@Brock: I think questions about the ATSB range calculations and presentation thereof comes down to why the 40,000 ft range calculation was not shown for the early turn at 18:28, which would have stretched the zone to the west. You think it was a deliberate omission. I would offer that there may have been technical reasons for believing the flight could not have started at 40,000 ft at 18:28.
The plane would be heavier at 18:28 than 18:40, and the highest altitude for MRC flight would be reduced. If you look at the LRC parameters in the table, you will see that there are no higher altitude values than 39,000 ft at 220 tons and 41,000 ft at 200 tons. I estimate the plane to weigh about 209 tons at 18:28 if it flew at LRC speeds and 35,000 ft up until that point. It may be that MRC is not allowed at 40,000 ft for the weight that ATSB has estimated for 18:28.
That said, I don’t trust the ATSB calculations. They say the calculations were performed for a constant airspeed. The MRC speed profile should be a function of Mach number, not airspeed, and the Mach number would vary with weight at a constant altitude. I have much more faith in the methodology adopted by some members of the IG and now also used by Bobby.
VIDEO: AirAsia Chief Investigator: other factors, not only weather, in QZ8501 crash
https://t.co/GshaVtULcN
@nihonmama, Wow! Thanks for this, I’ve tweeted it out, very significant. Not a huge surprise that investigators have concluded the crash was caused by a combination of weather and other factors (presumably mechanical and/or human factors) but great to hear that they feel that they now completely understand the chain of events. Big mystery now is when do the rest of us get to find out.
@Jeffwise:
My pleasure. Just saw your tweet. Thanks 😉
I’ll just say — that was an interesting interview…
@Victor: thanks for your comments. I concede every factual statement you make – and am glad you are skeptical of the ATSB perf limit – but disagree on two points:
1) No, it does not come down to JUST the FL400 path’s ommission. The FL350 path’s truncation is even more damning. The two paths should have nearly the exact same length in each graph – yet they are significantly different. The COMBINED effect of omission AND truncation is what concerns me.
2) Between Figs.2 and 3, all that is supposed to be changing is the FMT timing. For each FLxxx, ALL other attributes – speed, altitude, weight or fuel – should remain the same, both initially and over time.
Accordingly, the plane’s weight at time of FMT should have absolutely no bearing on the feasibility of any particular altitude/speed combination. If I can achieve FL400 by 18:40, then turn south and exceed the 7th arc by x nmi, then I can turn at 18:28, climb to FL400 by 18:40, and exceed the 7th arc by those same x nmi. Period.
@ Victor I:
” It may be that MRC is not allowed at 40,000 ft for the weight that ATSB has estimated for 18:28.”
The airplane does not have sufficient thrust to reach the altitudes that are blank in the table. The optimum altitudes are “shaded” in the original (lost in the copy), and the last field altitude is already sub-optimal range-wise.
@Brock: You said, “If I can achieve FL400 by 18:40, then turn south and exceed the 7th arc by x nmi, then I can turn at 18:28, climb to FL400 by 18:40, and exceed the 7th arc by those same x nmi. Period.”
I am not disagreeing with this statement. However, your scenario is not consistent with maintaining a constant altitude after the turn. I am not defending the ATSB’s rationale. Rather, I am trying to explain why they may have chosen to not include that scenario, as nonsensical as it may seem to you. As I said, I have more fundamental problems with their technical approach and so I ignore the results.
@Gysbreght: The blank entries are either related to insufficient thrust or just poor performance. The point is, the omission of the 40,000 ft curve for the earlier turn could be related to the higher weight at the time of the turn.
@ Victor I:
Second sentence – agreed.
If you consider insufficient thrust to be poor performance I agree also with the first sentence.
Victor,
I think these days paracetamol is the most popular medicine against headache (Tylenol is the most well-known) rather than aspirin.
You are probably mistaken about VAMPI, MEKAR and NILAM. You say “It also seems to have changed direction at MEKAR along N571 as the BFO at 18:28 suggests an azimuth of around 297 deg”. 18:28 corresponds to the time when MH370 was supposed to reach NILAM, shortly after the radar contact was lost (18:22), while the minor turn occurred earlier. Strictly speaking, MH370 followed only VAMPI->MEKAR section of N571, and it was heading to NILAM, which also belongs to N571. There is a chain of waypoints: IGREX, EMRAN, SAMAK, IGOGU, ANOKO, NOPEK, located at the same longitude west of NILAM, and ANOKO is the best candidate in terms of the heading. LAGOG, APASI and DOTEP are the next western candidates, among which LAGOG appears to be the most suitable for a landing attempt at Car Nikobar. Also I guess 18:28 is just a right time to initiate descent if the intent was to land at Aceh or Maimun Saleh. Due to almost symmetric Doppler at 18:28 (Z-component of Inmarsat satellite was small, 15-20 m/s), a turn to the North, or NW is also possible. The path NILAM->IGOGU->ISBIX suggested by IG conflicts with the logic. At least mine.
I understood the difference between us: I am trying to create a scenario that would be consistent with the data I am aware of, while you are trying to get rid of the data that do not match your scenario.
@Victor – If you concede that this is a nonsensical basis for omitting FL400, I will concede the JIT may have used it – in bad sense, but good faith.
Can we then turn to why they would dock FL350 several dozen nautical miles for the sin of turning 12 minutes earlier?
For the sake of anyone new to the convo: I’ve shown each of wind, sat drift, and earth’s shape to be immaterial in a prior thread.
Brock,
after Bobby’s comment, I would be pretty much interested to know how possible altitude changes 17:25-18:22 affect the remaining fuel. In contrast to IG, I don’t think 10-15 min at 7 km altitude would significantly affect the average airspeed. If you take a look at Bobby’s table, Mach = 0.77 is achievable at 25,000 ft. Take into account the air temperature, which affects Mach. But the remaining fuel could really be notably affected.
@sk999: I fear that you are mis-interpreting the Wiki report relating to Korean 007. I think also, that the insertion of the word “magnetic” in just a couple of places leads to that mis-interpretation.
If the ground track is depicted correctly [I’ll accept your 260 degT departing from Anchorage] then because the magnetic declination at that point was about 22deg E, the magnetic heading indicated should have been 292DegM [not 240]. Maintaining that heading over Sakhalin Island [where the deviation is about 8 Deg W] would put the True track at 300 deg. This does not fit with the track indicated.
What the report does not say, and I’m surprised, is that a heading hold track is subject to wind. The course deviation illustrated in the Wiki report is more likely the result of wind influences in the area at the time.
It would be perfectly normal to depart on a Mag vector under instruction from ATC, or as part of a standard procedure, because all instructions are given with Mag references. But there is no practical application for a magnetic heading or track hold, over an extended period of time.
Whoops, got my E and W mixed up while determining Mag deviation. Please disregard last post.
Flitzer_Flyer
I will not disregard your last post because it hits on a few useful points.
First, it took me 3 tries to figure out how a magnetic route would work. The third time I did it by visualizing the route with the aid of my old Boy Scout compass to measure azimuth, first pointing the big arrow on it to true North and getting an az of 260, then rotating it around to point towards Hudson’s Bay and … oh wait, the az is now 240. That’s the magnetic bearing.
The second point – I am not a pilot, so I have no first-hand experience, but if ATC is giving out instructions with Mag references, how does a B-777 pilot dial those in?
The third point – you say “… there is no practical application for a magnetic heading or track hold, over an extended period of time.” Exactly. I try to be a hands-on person, but I don’t have ready access to either a B-777 or a simulator to figure out what really happens. Where can one find an actual test of this impractical application of hold mode? That is when I stumbled on KA-007.
sk999: a couple of thoughts occurred to me while out for a cycle ride just now. The Wiki map is a Mercator projection. Is the course accurately depicted?
Carrying out ATC instructions is easy. Make sure the True/Norm switch is in the Norm position so that heading and track displays are referenced to Mag north. Then it is possible to turn onto a Mag referenced track or heading, possibly using Hdg Sel.
The Wiki report of the investigation into Korean 007 is pretty superficial. The FDR info ought to have given precise details of the aircraft configuration and the precise track should be known. And in this report the wind wasn’t mentioned. That is pretty important in a Hdg Hold mode.
The old boy scout trick works, if you know where true north really is. These days a smartphone app will allow you to select either true or magnetic. So does a GPS, and it is a lot easier following a GPS track whilst flying than trying to keep the mag compass steady.
@Gysbreght,
Airliners such as 9M-MRO can and routinely do 4,000 foot step climbs. That is, when the aircraft is 2,000 feet below the ideal altitude in Long Range Cruise, it will climb 4,000 feet so it is (temporarily) 2,000 feet above the current ideal altitude. Thrust is sufficient to do this maneuver without risk. That is why there is always an entry in the table for an altitude 2,000 feet above the ideal LRC altitude.
At the time of the FMT, the 209 MT total weight indicates a 38,000 foot ideal LRC altitude. A step climb to 2,000 feet above that level to 40,000 feet is not out of the ordinary. With no ability to communicate with ATC, and with the FMS routinely and periodically recommending an altitude change, it would be a simple matter for a pilot to concur with the recommended change and climb higher.
So what is a safer assumption – The Indon radar – demonstrably intact before and after MH370 went missing – wasn’t working on the night, or the plane dropped under it?
@Brock,
There are two geometric effects that change the Performance Limit for different Final Major Turn times. Let us assume the route continued past the last radar location at 18:22 at the same bearing of about 290 degrees at a ground speed of about 490 knots (8.2 NM / minute). Thus between 18:28 and 18:40 the aircraft traveled an additional 98 NM before the turn. At 290 degrees bearing, the aircraft moved 34 NM north and 92 NM west during this twelve minutes. Thus the 18:40 turning point was approximately 34 NM north and 92 NM west of the 18:28 turning point. From its turning point, the 18:40 route must also be 98 NM shorter than the 18:28 route from its turning point. So, to a first order approximation, the 18:28 route will be about 98 + 34 = 132 NM “longer” from an origin that is 92 NM farther east.
These calculations assume a single Final Major Turn. This assumption may not turn out to be correct, but the ATSB’s curves are based on the same assumption – that of “a turn shortly after the last radar contact”.
From a comparison of the ATSB’s Figures 2 and 3 for the 35,000 foot altitude cases, the plotted 18:28 route is at most 1 degree further south (~60 NM). This is less than ½ the expected 132 NM difference (2.2 degrees). So, along with other less than optimum assumptions by the ATSB in determining its performance limit estimates, there appears to be a significant disconnect between the expected latitude difference and their plotted end point latitude difference for 18:28 and 18:40 turns.
Using the same method as Victor and applying it to the Trent 892 engines, and allowing for an average 2% PDA, I have found Long Range Cruise routes that intersect the 7th arc as far west as 84.0E. So my best estimate of the Performance Limit intersects the 7th Arc as much as 2.5 degrees farther west in longitude than the current ATSB Search Area (which ends at 86.5E). This is approximately 150 NM further SW along the arc. My parametric studies have convinced me that this region is of comparable probability to the region currently being searched by the ATSB, and I recommend they extend westward to 84E longitude.
@Oleksandr,
If you read my post again, I said I thought the flight crew might have been incapacitated as early as ~18:30. You ask why they did not use the satellite phone to make a distress call at 18:28, when the SDU was booted up, Perhaps the normally simple act of breathing might have been their major concern at that point in time.
We also don’t know whether the satellite phone link was actually functioning then. Recall that it has been reported that the 18:40 call to 9M-MRO apparently did not connect sufficiently to actually ring in the cockpit. If the crew tried to place an outgoing call, how do we know it would have actually connected with the ground station? Perhaps some part of the system necessary for phone calls, but not necessary for logging on, was malfunctioning or without power.
Here is a tweet linking you to a comprehensive report summarizing my investigation of MH370 search leadership since April:
https://twitter.com/Brock_McEwen/status/556337243594317824
Thanks to all on this thread who helped (however indirectly) to write it, and to all who take the time and energy to read it.
@Brock
While I may disagree with some of your contentions, I have nothing but praise for your commitment to both the truth and the best interest of the families.
I really do admire your tenacity and your inquisitive mind.
The energy, drive and determination you have exhibited in an effort to further a greater transparency is very much appreciated!!!
Best regards,
Spencer
@ Bobby:
“That is why there is always an entry in the table for an altitude 2,000 feet above the ideal LRC altitude.”
No, I admire your inventiveness but that is not correct. The table you provided gives the LR cruise control data for the altitudes that can be reached at Maximum Climb Thrust with a residual rate of climb of 300 fpm. The optimum cruise altitude is within the shaded areas. For some weights an altitude above the shaded area can be reached, for others not.
Presumably the FCOM page preceding the page you provided gives the All Engine Long Range Cruise Maximum Operating Altitude.The FCOM also provides the following explanatory text:
“Long Range Cruise Maximum Operating Altitude
These tables provide the maximum operating altitude in the same manner
as the FMC. Maximum altitudes are shown for a given cruise weight and
maneuver capability. Note that this table considers both thrust and buffet
limits, providing the more limiting of the two. Any data that is thrust
limited is denoted by an asterisk and represents only a thrust limited
condition in level flight with 300 ft/min residual rate of climb. Flying
above these altitudes with sustained banks in excess of approximately 21°
may cause the airplane to lose speed and/or altitude.
Note that optimum altitudes shown in the tables result in buffet related
maneuver margins of 1.5g (48° bank) or more. The altitudes shown in the
table are limited to the maximum certified altitude of 43100 ft..”
@ Bobby:
P.S. I forgot to mention that above the flat-rated temperature the thrust-limited altitude varies with ambient temperature.
Hi Bobby,
I think a “simple act of breathing” can hardly be a reason, because of the following:
(1) It is hard to imagine somebody recovering SDU and entering WPs till 18:25 having severe difficulty to breathe to get incapacitated in as short as 5 minutes, and not attempting to land at Penang or even descent to acceptable levels to depressurize the cabin. As a matter of fact, the descent could really take place if you assume the radar altitude is correct.
(2) At 18:22 MH370 still was heading to somewhere else, not southward. If the last WP was entered after 18:22, the “simple act of breathing” is not convincing: they had time to enter at least two waypoints for some purpose, but did not have time to take care of the air to support lives or report emergency. If the last WP was entered before 18:22, the sequence of at least 2 last WPs does not make sense.
I agree, the phone call 18:40 could be too short, or even phone itself could be spoilt. What is interesting to me is that SDU came back shortly after AP was switched on. If you assume that the power was restored by ~18:00 as a result of human actions, this explains switching on AP around this time, followed by SDU. Initially I thought AP/FMS can come back automatically on the power restoration, but Mike says it will not. In case of hijacking, unanswered call 18:40 could also be explained. However, in both these scenarios, there is no reason to suggest the crew was incapacitated by 18:30 or even 18:40. It could happen much later, even after 19:40. In other words, the phone call 18:40 could be unanswered for the same reason as why a potential call at 18:25 was not made.
@Brock: I will agree that if the ATSB omitted the 40,000-ft case for the early turn based on the weight at 18:28, it is nonsensical.
I do not understand the methodology for how the ATSB came up with their maximum range paths. You ascribe any errors in the results to deception. I think it is more likely that the errors are unintended. I don’t think either of us can definitively prove the other wrong.
I think it is helpful for you to show any inconsistencies in the ATSB’s logic, and ask the ATSB to respond. I choose to ignore their range results and replace the results with a methodology I think is more accurate.
@Gysbreght: Can you provide a link to the FCOM document you cite? For the RR engines, most of us have nothing but the LRC table. The more complete documentation would be very helpful. (We have the more complete Flight Planning and Performance Manual for the GE version of the B777-200ER.)
@Jeff
something OT(?):
back to your nice article about brave swimmer, tweeted on Jan/15 goo.gl/ip4yX3
everytime I see any motivation and personal development websites, not to mention any references to Cruise, I am now probably paranoid to some extent and my dashboard starts flashing with red-alerts… can you comment on this too?
https://www.youtube.com/watch?v=EIy5hfgYxrA