Malaysian Airlines MH370 contact lost
Join Date: Dec 2006
Location: Florida and wherever my laptop is
Posts: 1,350
Likes: 0
Received 0 Likes
on
0 Posts
Much discussion has centred around heading changes and the complications of entering these into the FMS.
I am not familiar with Boeing practice (777 pilots please comment) but many aircraft have a large 4 position knob on the centre console which simply changes the current heading in 90 degree steps. This is used when flying a holding pattern.
In the event of a depressurisation or other serious event it would make sense to simply turn the knob 90deg right, wait a short time to clear the airway then right again to head for home. No complicated FMS entries required.
Is the heading flown to the Indian Ocean 180deg to a heading which the aircraft would be expected to be flying during its normal route ?.
I am not familiar with Boeing practice (777 pilots please comment) but many aircraft have a large 4 position knob on the centre console which simply changes the current heading in 90 degree steps. This is used when flying a holding pattern.
In the event of a depressurisation or other serious event it would make sense to simply turn the knob 90deg right, wait a short time to clear the airway then right again to head for home. No complicated FMS entries required.
Is the heading flown to the Indian Ocean 180deg to a heading which the aircraft would be expected to be flying during its normal route ?.
To fly a different mode requires specific inputs either track mode or to a specified waypoint. Someone needed to be there to make those inputs after Malaysian radar had lost contact on the westward flying aircraft.
Join Date: Jul 2009
Location: Atlanta, GA USA
Age: 60
Posts: 183
Likes: 0
Received 0 Likes
on
0 Posts
Sheep Guts: The Frequency is 37.5 KHz which is on the Low Frequency LF band 30khz -300khz
Join Date: Mar 2009
Location: Perth Western Australia
Age: 57
Posts: 808
Likes: 0
Received 0 Likes
on
0 Posts
Perhaps the SAR world needs some sort of clearing house, a bit like Chatham House, where information from credible and classified sources can be pooled without disclosing where or how it was obtained. Maybe if this had existed on March 8th we could have saved lives, if there were lives still to be saved.
It is the only way to go, and yes some of that information will be wrong and will need to change there pattern as more information arises.
The Frequency is 37.5 KHz which is on the Low Frequency LF band 30khz -300khz
Frequency Spectrum definitions and description here
Frequency Spectrum definitions and description here
How many times, audio, versus electromagnetic
Bleve:
In alternate nav the CDUs do not have a navigation database. All new waypoints have to be entered by lat/long.
In alternate nav the CDUs do not have a navigation database. All new waypoints have to be entered by lat/long.
I've said this before. The FMC is not required (and Boeing does not have 90 degree options). In a premeditated event the whole scenario can be done on a mobile phone or ipad using an FMC app, then HDG SEL used to navigate by. It does not need pilot training to do that. Just follow the yellow brick (magenta) road. VNAV is the difficult bit.
I happened to be listening to Oz marine HF frequencies yesterday and seems around every 3 hours there is a pan pan broadcast re MH370 to remind ships entering the area to keep a lookout. Im on the east coast of Oz but the broadcasts were fairly clear.
Join Date: Jan 2008
Location: Australia - South of where I'd like to be !
Age: 59
Posts: 4,261
Likes: 0
Received 0 Likes
on
0 Posts
The Media (newspapers in Aus) are saying a major shift in the search area has occurred.
The search area for missing Malaysia Airlines flight MH370 has been updated after a new credible lead was provided to the Australian Maritime Safety Authority (AMSA).
As a result today’s search will shift to an area 1,100 kilometres to the north east based on updated advice provided by the international investigation team in Malaysia.
The Australian Transport Safety Bureau (ATSB), Australia’s investigation agency, has examined this advice and determined that this is the most credible lead to where debris may be located.
The new search area is approximately 319,000 square kilometres and around 1,850 kilometres west of Perth.
The new information is based on continuing analysis of radar data between the South China Sea and the Strait of Malacca before radar contact was lost.
It indicated that the aircraft was travelling faster than previously estimated, resulting in increased fuel usage and reducing the possible distance the aircraft travelled south into the Indian Ocean.
ATSB advises the potential flight path may be the subject of further refinement as the international investigative team supporting the search continues their analysis.
The Australian Geospatial-Intelligence Organisation is re-tasking satellites to image the new area. Weather conditions have improved in the area and ten aircraft are tasked for today’s search.
They include two Royal Australian Air Force (RAAF) P3 Orions, a Japanese Coast Guard jet, a Japanese P3 Orion, a Republic of Korea P3 Orion, a Republic of Korea C130 Hercules, a Royal New Zealand Air Force (RNZAF) P3 Orion, a Chinese military Ilyushin IL-76, a United States Navy P8 Poseidon aircraft, and one civil jet acting as a communications relay.
A further RAAF P3 Orion has been placed on standby at Pearce to investigate any reported sightings.
There are now six vessels relocating to the new search area including HMAS Success and five Chinese ships.
AMSA and the ATSB will hold a press conference at 1430 (AEDT) to provide more details on the new search area.
The search area for missing Malaysia Airlines flight MH370 has been updated after a new credible lead was provided to the Australian Maritime Safety Authority (AMSA).
As a result today’s search will shift to an area 1,100 kilometres to the north east based on updated advice provided by the international investigation team in Malaysia.
The Australian Transport Safety Bureau (ATSB), Australia’s investigation agency, has examined this advice and determined that this is the most credible lead to where debris may be located.
The new search area is approximately 319,000 square kilometres and around 1,850 kilometres west of Perth.
The new information is based on continuing analysis of radar data between the South China Sea and the Strait of Malacca before radar contact was lost.
It indicated that the aircraft was travelling faster than previously estimated, resulting in increased fuel usage and reducing the possible distance the aircraft travelled south into the Indian Ocean.
ATSB advises the potential flight path may be the subject of further refinement as the international investigative team supporting the search continues their analysis.
The Australian Geospatial-Intelligence Organisation is re-tasking satellites to image the new area. Weather conditions have improved in the area and ten aircraft are tasked for today’s search.
They include two Royal Australian Air Force (RAAF) P3 Orions, a Japanese Coast Guard jet, a Japanese P3 Orion, a Republic of Korea P3 Orion, a Republic of Korea C130 Hercules, a Royal New Zealand Air Force (RNZAF) P3 Orion, a Chinese military Ilyushin IL-76, a United States Navy P8 Poseidon aircraft, and one civil jet acting as a communications relay.
A further RAAF P3 Orion has been placed on standby at Pearce to investigate any reported sightings.
There are now six vessels relocating to the new search area including HMAS Success and five Chinese ships.
AMSA and the ATSB will hold a press conference at 1430 (AEDT) to provide more details on the new search area.
Satellites are poor search tools
Satellites are just as bound by optics constraints as earthbound photographers, so the resolution of an image 20+ miles square is not at the centimeter level. High resolution zooms can be had, but cover a very small field, so the problem becomes telling the satellite where to look exactly.
Drifting debris beneath partial clouds need to be pinpointed by human interpreters, but will have moved by the time that is done. Consequently the searchers cannot direct the higher resolution images a satellite could take fast enough to do any good.
A real time satellite image analysis with immediate high resolution targeting might be available to the military, but none of the commercial earth observation satellites have that. Hence the 2-3 day lag between the taking of the satellite pictures and the public finding of possible debris.
Drifting debris beneath partial clouds need to be pinpointed by human interpreters, but will have moved by the time that is done. Consequently the searchers cannot direct the higher resolution images a satellite could take fast enough to do any good.
A real time satellite image analysis with immediate high resolution targeting might be available to the military, but none of the commercial earth observation satellites have that. Hence the 2-3 day lag between the taking of the satellite pictures and the public finding of possible debris.
Join Date: Mar 2014
Location: Below glidepath
Posts: 15
Likes: 0
Received 0 Likes
on
0 Posts
There seems to be some confusion on the black box pinger.
The pinger on the black boxes use sound waves at 37.5 kHz, and require sonar detectors, which are essentially sophisticated microphones. Even though this falls in the LF band of 30kHz to 300kHz, the LF designation is for radio, or rf, signals, not sound. 37.5 kHz is ultrasound to us humans.
Sound signals are compression waves - they vibrate the molecules back and forth in the direction they are traveling. Radio, or light, waves are called transverse waves. They consist of an electric, or E field, and a magnetic, or H field, which are both at right angles to each other and to the direction they are traveling.
As they propagate out from a sound source, both sound and radio waves are attenuated by 1/(4*pi*r^2), which is the surface area of a sphere - this is the main reason why sounds or the brightness of lights get weaker the further one moves away from the source. In addition, in water, it appears that sound at 37.5 kHz is attenuated by an additional 0.1 dB/kilometer due to absorption, meaning that sound waves are barely affected by the water. Radio waves at 35 kHz are attenuated by about 6000 dB / kilometer due to the conductivity of salt water, which says the radio wave are essentially totally absorbed.(Underwater Radio Communication by Lloyd Butler VK5BR). This is why they use sound waves instead of radio waves.
However, this does not take into account thermoclines, which, from what I understand, can cause almost total reflection of a sound wave.
Hope this helps.
The pinger on the black boxes use sound waves at 37.5 kHz, and require sonar detectors, which are essentially sophisticated microphones. Even though this falls in the LF band of 30kHz to 300kHz, the LF designation is for radio, or rf, signals, not sound. 37.5 kHz is ultrasound to us humans.
Sound signals are compression waves - they vibrate the molecules back and forth in the direction they are traveling. Radio, or light, waves are called transverse waves. They consist of an electric, or E field, and a magnetic, or H field, which are both at right angles to each other and to the direction they are traveling.
As they propagate out from a sound source, both sound and radio waves are attenuated by 1/(4*pi*r^2), which is the surface area of a sphere - this is the main reason why sounds or the brightness of lights get weaker the further one moves away from the source. In addition, in water, it appears that sound at 37.5 kHz is attenuated by an additional 0.1 dB/kilometer due to absorption, meaning that sound waves are barely affected by the water. Radio waves at 35 kHz are attenuated by about 6000 dB / kilometer due to the conductivity of salt water, which says the radio wave are essentially totally absorbed.(Underwater Radio Communication by Lloyd Butler VK5BR). This is why they use sound waves instead of radio waves.
However, this does not take into account thermoclines, which, from what I understand, can cause almost total reflection of a sound wave.
Hope this helps.
Join Date: Oct 2008
Location: LAX
Posts: 68
Likes: 0
Received 0 Likes
on
0 Posts
AMSA: Due to a "credible lead", the search area is being shifted 1100 km to the northeast. Press conference at 1430 AEDT to discuss.
http://www.amsa.gov.au/media/documen...70Update23.pdf
http://www.amsa.gov.au/media/documen...70Update23.pdf
Join Date: Apr 2011
Location: Cork, Ireland
Age: 55
Posts: 54
Likes: 0
Received 0 Likes
on
0 Posts
Satellites are just as bound by optics constraints as earthbound photographers, so the resolution of an image 20+ miles square is not at the centimeter level. High resolution zooms can be had, but cover a very small field, so the problem becomes telling the satellite where to look exactly.
Drifting debris beneath partial clouds need to be pinpointed by human interpreters, but will have moved by the time that is done. Consequently the searchers cannot direct the higher resolution images a satellite could take fast enough to do any good.
A real time satellite image analysis with immediate high resolution targeting might be available to the military, but none of the commercial earth observation satellites have that. Hence the 2-3 day lag between the taking of the satellite pictures and the public finding of possible debris.
Drifting debris beneath partial clouds need to be pinpointed by human interpreters, but will have moved by the time that is done. Consequently the searchers cannot direct the higher resolution images a satellite could take fast enough to do any good.
A real time satellite image analysis with immediate high resolution targeting might be available to the military, but none of the commercial earth observation satellites have that. Hence the 2-3 day lag between the taking of the satellite pictures and the public finding of possible debris.