quinta-feira, 2 de outubro de 2014

Display Units on Boeing's Flight Deck MUST BE Updated for WI-FI Network



Displays Units on Boeings Went Blank Under Interference from In-plane WI-FI network.

  Airline equipment manufacturer Honeywell's new Phase 3 Display Units (DUs) reportedly blanked out during a test because of interference from an in-plane wi-fi network.

 The DUs blanked out while they were undergoing airline electromagnetic interference (EMI) certification testing for Wireless broadband.

 The test failure has prompted aircraft maker Boeing to stop installing in-flight wi-fi connectivity systems on all of its planes including widebody aircraft.

 Display blanking durations of as long as six minutes were observed during testing

 Boeing is using RTCA DO-307 - which covers Aircraft Design and Certification for Portable Electronic Device (PED) Tolerance - as guidance.

When a manufacturer goes through qual testing in the lab for RTCA DO-307 (as outlined in the FAA's advisory circular AC-20-164), it accounts for both the frequency and energy field value at levels well beyond what a cell phone or Wi-Fi would produce if its near that equipment.

The value covers a range between 100 MHz to 8 GHz. To put that into perspective, Wi-Fi operates at 2.4 GHz or 5 GHz and cell phones operates as low as 460 MHz and as high as 2.17 GHz. So yes, the levels tested far exceed all normal scenarios, but for good reason. Who wants people with malicious intent (oh, say, terrorists) to take RF aim at the cockpit? Uh, nobody, except the terrorists.

If the equipment passes muster, it is considered to be T-PED (tranmissing portable electronic device) tolerant, and that's what Boeing and others are working towards.

 


FAA AIRWORTHINESS DIRETIVE – AD

 This AD is effective [INSERT DATE 35 DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER].

 We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes, and Model 777 airplanes. This AD was prompted by testing reports on certain Honeywell phase 3 display units (DUs). These DUs exhibited susceptibility to radio frequency emissions in WiFi frequency bands at radiated power levels below the levels that the displays are required to tolerate for certification of WiFi system installations. The phase 3 DUs provide primary flight information including airspeed, altitude, pitch and roll attitude, heading, and navigation information to the flightcrew.

 This AD requires replacing the existing phase 3 DUs with phase 1, phase 2, or phase 3A DUs, and for certain replacement DUs, installing new DU database software.

We are issuing this AD to prevent loss of flight-critical information displayed to the flightcrew during a critical phase of flight, such as an approach or takeoff, which could result in loss of airplane control at an altitude insufficient for recovery, or controlled flight into terrain.

 Clarification of Cause of Unsafe Condition

 The cause of the unsafe condition stated in the Discussion section of this AD is a known susceptibility of the Phase 3 DUs to RF transmissions inside and outside of the airplane. This susceptibility has been verified to exist in a range of RF spectrum (mobile satellite communications, cell phones, air surveillance and weather radar, and other systems), and is not limited to WiFi transmissions.

This AD was prompted by testing reports on certain Honeywell phase 3 display units (DUs). These DUs exhibited susceptibility to radio frequency emissions in WiFi frequency bands at radiated power levels below the levels that the displays are required to tolerate for certification of WiFi system installations. The phase 3 DUs provide primary flight information, including airspeed, altitude, pitch and roll attitude, heading, and navigation information, to the flightcrew. We are issuing this AD to prevent loss of flight-critical information displayed to the flightcrew during a critical phase of flight, such as an approach or takeoff, which could result in loss of airplane control at an altitude insufficient for recovery, or controlled flight into terrain.

 (1) For Model 737 airplanes: Remove all phase 3 common display system (CDS)

DUs and replace with phase 1, phase 2, or phase 3A CDS DUs. If any phase 3 CDS DUs are replaced with phase 3A CDS DUs, replace the phase 3 CDS DUs and install new database software into the display electronics units, in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-31-1471,dated November 29, 2012.

 (2) For Model 777 airplanes: Remove all phase 3 DUs and replace with phase 1, phase 2, or phase 3A DUs. If any phase 3 DUs are replaced with phase 3A DUs, replace the phase 3 DUs and install the DU database software into the left and right airplane information management system core processor module/graphics generator, in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 777-31-0187, dated November 29, 2012.


terça-feira, 19 de agosto de 2014

Citation XLS - Stabilizer System Caution -





Cessna Citation XLS

Horizontal Stabilizer  Description
 
Descrição do Estabilizador Horizontal
The two-position horizontal stabilizer system
automatically repositions the aircraft’s horizontal stabilizer to improve flight characteristics.
 
O sistema de estabilizador horizontal de duas posições reposiciona o estabilizador horizontal da aeronave para melhorar as características do voo.
 
The horizontal stabilizer positions to one
of two positions: a +1 degree (cruise) or –2 degree (takeoff). The angle of incidence position depends on the flap handle position and airspeed by moving the entire horizontal stabilizer. When airspeed is greater than 215 knots ±10, the airspeed switch disables the arming valve preventing stabilizer movement to the –2° position.
As posições do estabilizador horizontal para uma das duas posições: uma de +1 grau (cruzeiro) ou -2 graus (decolagem). A posição do ângulo de incidência [ponpensação] depende da posição da alavanca dos flaps e da velocidade aerodinâmica ao movimentar o estabiizador horizontal inteiro. Quando a velocidade estiver maior do que 215 Knots  ± 10, o interruptor de velocidade incapacita a válvula de armar  impedindo o movimento do estabilizador para a posição -2°.


Airspeed Switch
 
Interruptor de Velocidade Aerodinâmica
The airspeed switch senses airspeed from the standby pitot static system and enables or disables the horizontal tail from downward movement towards the takeoff and approach position or upward movement towards the cruise position— based upon the airspeed sensed. The horizontal tail is enabled if airspeed is less than 215 ±10 knots; or disabled it if airspeed is greater than 215 ±10 knots. It is behind the copilot side panel, above the armrest.
O interruptor de velocidade aerodinamica detecta a velocidade do sistema de pitot estático auxiliar e habilita ou desabilita a cauda horizontal [estabilizador] do movimento para baixo na direção da posição decolagem e aproximação ou do movimento para cima na direção da posição cruzeiro — baseado na velocidade aerodinamica sentida. A cauda horizontal é habilitada se a velocidade estiver menor que  215 ± 10 knots; ou desabilitada, se a velocidade estiver  maior que 215 ± 10 knots. Ele [interruptor] está atrás do painel lateral do co-piloto, acima do apoio de braço.


The STAB MIS COMP light illuminates to indicate the horizontal stab position does not
agree with the flap handle position after 30 seconds of travel. (Unless the Landing Gear
is also selected, then the delay is 40 seconds).
A luz STAB MIS COMP ilumina-se para indicar que a posição do estabilizador horizontal não corresponde com a posição da alavanca de flaps após 30 segundos de movimentação dos flaps. (A menos que o Trem de Pouso esteja também selecionado, então o atraso é 40 segundos).




Stabilizer Monitoring System
 
Sistema de Monitoramento do Estabilizador
The two-position horizontal stabilizer control system is controlled by a flap-handle position and airspeed. With the flap-handle in the FLAPS UP detent position the horizontal stabilizer has an incidence of +1°. With the flap handle in any position other than the FLAPS UP detent and the airspeed no greater than 215 ± 10kts, the horizontal stabilizer has an incidence of –2°.
O sistema de controle do estabilizador horizontal com duas posições é controlado por uma alavanca de posição dos flaps e a velocidade aerodinâmica. Com a alavanca de flaps na posição do batente FLAPS UP [flaps recolhidos], o estabilizador horizontal tem uma incidência [desvio de compensação] de + 1°. Com alavancaa  de flaps em qualquer posição diferente  do batente  FLAPS UP e a velocidade não superior a 215 ± 10 knots  [398 Km/h ± 18 Km/h, uma margem entre 379 e 416 Km/h], o estabilizador horizontal tem uma incidência [desvio de compensação] de – 2°.
 
 
The horizontal stabilizer cannot
move down to an incidence of –2° if the
airspeed is greater than 215 ± 10 kts. It is prevented from moving in either direction if the landing gear is in motion. The two-position tailprinted circuit board (N2017) monitors the horizontal stabilizer position. The circuit board flashes the amber STAB MIS COMP annunciator and illuminates the MASTER CAUTION RESET switchlight under the following conditions:
 
O estabilizador horizontal não pode mover para baixo com uma incidência de –2° [menos 2°], se a velocidade for superior a 215 ± 10 knots. Ele [estabilizador]  é impedido de se mover em qualquer direção, se o trem de pouso estiver em movimento [recolhendo ou baixando) . A Placa de circuito impresso de duas posições (N2017) monitora a posição do estabilizador horizontal. A placa do circuito faz piscar a luz âmbar de anúncio STAB MIS COMP e ilumina a luz MASTER CAUTION RESET  sob as seguintes condições:
• Anytime the flap handle is not in the
“FLAPS UP” detent position and the stabilizer has not reached the incidence of
–2° within the predetermined time limit
of 30 seconds.
 
• A qualquer momento que a alavanca dos  flaps não estiver na posição do batente "FLAPS UP" e o estabilizador não tiver atingido a incidência de –2° dentro do limite de tempo pré-determinado de 30 segundos.
• Anytime the flap handle is in the “FLAPS
UP” detent position and the stabilizer has
not reached the incidence of +1 within the
predetermined time limit of 30 seconds.
 
• A qualquer momento que a alavanca de flaps estiver  na posição do batente  "FLAPS UP" e o estabilizador não tiver chegado a incidência de + °1 dentro do limite de tempo pré-determinado de 30 segundos.
• Anytime the PCB senses flap handle selected up and flap-handle is selected
down concurrently.
• Sempre que a Placa de Circuito Impresso sente o manuseio de flaps selecionado para cima e a alavanca  de flaps  estiver selecionada para baixo simultaneamente.


domingo, 17 de agosto de 2014

Citation PR-AFA - Non-Precison Instruments Approach Procedure


DOWNLOAD (com audio)



BLOQUEIO, é a primeira passagem da aeronave sobre a antena do auxílio à navegação quando  ela  chega da descida do nível de cruzeiro. Ela passa sobre a antena na altitude de início do procedimento de pouso por instrumentos e se AFASTA em determinado curso.

REBLOQUEIO, é a segunda passagem da aeronave sobre a mesma antena do auxílio à navegação quando ela retorna do AFASTAMENTO e via de regra passará numa altitude mais baixa e prossegue para o pouso.

Não se deve usar a terminologia REBLOQUEIO para uma aeronave que já está voando em órbita, pois cada passagem sobre a antena do auxílio,  estando orbitando, é um BLOQUEIO.

O termo REBLOQUEIO só existe para a aeronave que efetuou o AFASTAMENTO logo após passar pela primeira vez  sobre a antena ao descer do nível de cruzeiro.

Transcrição do trecho da fraseologia emitida a partir do Citation XLS PR - AFA:

"Papa, Romeo, Alpha, Fox[trot], Alpha,
 
vai fazer a ECHO UNO, é ... da pista Três, Cinco,
 
vai fazer o BLOQUEIO de Santos e o REBLOQUEIO, OK?

BLOQUEIO  e afastar direto".


O piloto usou a fraseologia internacional padrão para informar as intenções para pouso em aeroporto que possui somente rádio-estação de comunicações. As informações acerca das  intenções devem ser transmitidas para o órgão de controle de tráfego aéreo ANTES de inciar o procedimento de aproximação para o pouso.

Até o momento, os dados concretos da investigação são:

A rádio-estação do aeroporto de Santos, operada pela Aeronáutica, confirmou que o piloto declarou a "arremetida", e o operador da rádio-estação perguntou, "quais suas próximas intenções", e a resposta foi, "vou aguardar a melhoria de condições do tempo" (foram as últimas palavras com o operador). Foi confirmado também que os Flaps e Trem de Pouso estavam recolhidos após a arremetida.


No entanto, se os Flaps demorarem para recolher totalmente (alavanca dos Flaps na posição ZERO grau) e a velocidade ultrapassar 215 Knots ± 10 enquanto os Flaps ainda estiverem sendo recolhidos, o Sistema de compensação automática do compensador (Elevator) do estabilizador desabilita o estabilizador para se mover para posição  +1° (mais um grau), o qual serve para o voo após a arremetida e cruzeiro.

Esta situação é alertada no painel de anúncio de falhas pela iluminação da luz âmbar

STAB MIS COMP e isso dispara a luz de alerta MASTER CAUTION  RESET.

O próximo evento ocorre em milésimos de segundo.

O nariz da aeronave é 'derrumado' violentamente (NÃO pelo piloto) e sim, pela condição do estabilizador imóvel, e se inicia uma descida vertiginosa e por mais que os pilotos tentem levantar o nariz do avião, não conseguem, pois necessitariam de muita força, uma vez que o estabilizador não se ajusta automaticamente em Nariz para  CIMA. O mergulho abrupto em baixa altitude e a velocidade cada vez mais aumentando, teoricamente, só seria interrompido se, e somente se, houvesse espaço aéreo vertical abaixo da aeronave para proceder a recuperação do mergulho.

Se a situação ocorrer no solodurante a corrida de decolagem, um alarma sera emitido para não decolar.

 A aeronave faz o mergulho íngreme independente das asas estarem niveladas. Esta condição de o nariz da aeronave ser ‘derrubado’ violentamente é exclusivamente devido ao turbilhonamento do ar que deixa o bordo de fuga das asas  e atinge o estabilizador, o qual não está com o ajuste automático de compensação para ele, em +1°. Esse turbilhonamento do ar ao atingir o estabilizador, fluindo por baixo dele, força violentamente a cauda do avião subir, e consequentemente o nariz da aeronave desce violentamente.

 

Em outro acidente com aeronave da Suiça do mesmo modelo e tipo de aeronave, a ocorrência foi acima de 2000 pés sobre o mar e os pilotos conseguiram recuperar o voo normal na altitude de 914 pés.

 




domingo, 20 de julho de 2014

Theater In The Ukraine Skies

 

Exact moment one of the MH17’s Flight Data Recorders was found by pro-Russia demander self-nominated “Novorossiya"

Momento exato que uma das “Caixas Pretas”  do voo MH17 foi encontrada por um dos sapadores pro-Russian que se entitulam “Novorossiya”.
 


Rota do Voo 17

O avião estava na Aerovia L980, a qual tinha permanecido aberta acima de 32000 pés durante o conflito na Ucrânia.

Antes do Voo MH17 decolar, a RUSSIA fechou mais de uma dúzia de aerovias em várias altitudes.

A rota que o Voo MH17 teria seguido estava somente aberta acima de 32000 pés.

Áreas restritas a voos antes do acidente de Quinta-feira (Traçado em vermelho pela FAA e em azul pelo Eurocontrol)


It also emerged that flight MH17 had initially filed a flight plan requesting to fly at 35,000ft above Ukrainian territory. On entering Ukrainian airspace, however, the plane's pilots were instructed to fly at 33,000ft by the local air traffic control due to other traffic. Malaysia Airlines said the pilots had to follow the lead of the local authorities.
 
Também emergiu que o voo  MH17 tinha inicialmente apresentado um plano de voo, solicitando voar a 35.000 pés acima do território ucraniano. Ao entrar no espaço aéreo ucraniano, no entanto, os pilotos do avião foram instruídos a voar a 33.000 pés pelo controle de tráfego aéreo local devido a outro tráfego. A Malaysia Airlines disse que os pilotos tinham de seguir o comando das autoridades locais.
Malaysia's transport minister, Datuk Seri Liow Tiong Lai, told a press conference: "MH17's flight path was a busy major airway, like a highway in the sky. It followed a route which was set out by the international aviation authorities, approved by Eurocontrol, and used by hundreds of other aircraft.
 
O ministro dos transporte da Malásia, Datuk Seri Liow Tiong Lai, disse numa conferência de imprensa: "a rota de voo do MH17 era uma aerovia principal ocupada, como uma autoestrada no céu. Ele seguiu uma rota a qual foi estabelecida pelas autoridades da aviação internacional, aprovada pela Eurocontrol e usada por centenas de outras aeronaves.
"MH17 flew at an altitude that was set and deemed safe by local air traffic control, and it never strayed into restricted airspace. The flight and its operators followed the rules. But on the ground, the rules of war were broken."
 
"MH17 voava a uma altitude que estava definida e considerada segura pelo controle de tráfego aéreo local, e ele nunca se desviou para dentro de espaço aéreo restrito. O vôo e seus operadores seguiram as regras. Mas no solo, as regras da guerra foram quebradas".
Malaysia Airlines was one of more than a dozen that flew the route on Thursday. Its flight MH17 was only a few miles from an Air India Boeing 787 and a Singapore Airlines 777 when it was shot down. The only restriction placed on the route by the Ukrainian government was that aircraft must remain above 32,000ft.
 
Malaysia Airlines foi uma das mais de uma dúzia que voou a rota na Quinta-feira. Seu vôo MH17 estava somente a poucas milhas de um Boeing 787 da Air India e um B 777 da Singapore Airlines quando ele foi abatido. A unica restrição colocada na rota pelo governo ucraniano era que as aeronaves deviam permanecer acima de 32.000 pés.

quarta-feira, 2 de julho de 2014

MH370 - The Aircraft Experienced a Power Failure



29 Jun 2014


Inmarsat, the company that officially analyzed flight data from MH370, has confirmed the assessment but says it does not know why the aircraft experienced a power failure.
 
Inmarsat, a empresa que oficialmente analisou dados de vôo do MH370, confirmou a avaliação, mas diz que não sabe por que a aeronave experimentou uma falha de energia.
 
"It does appear there was a power failure on those two occasions," Chris McLaughlin, from Inmarsat, told The Telegraph. "It is another little mystery. We cannot explain it. We don't know why. We just know it did it."
 
"Parece que houve uma falha de energia nessas duas ocasiões," Chris McLaughlin, da Inmarsat, disse ao The Telegraph. "É mais um pouco de mistério. Nós não podemos explicar. Não sabemos o porquê. Só sabemos que foi isso. "
 
The Australian report released by Australian authorities has revealed that the Boeing 777 attempted to log on to Inmarsat satellites at 2.25am, three minutes after it was detected by Malaysian military radar.
 
O relatório australiano divulgado por autoridades australianas, revelou que o Boeing 777 tentou fazer log-on nos satélites da Inmarsat às 02:25 AM, três minutos depois que foi detectado pelo radar militar da Malásia.
 
This was as the plane was flying north of the Indonesian island of Sumatra. The aircraft had already veered away from the course that would have taken it to its destination of Beijing, but had not yet made its turn south towards the Indian Ocean.
Isto foi quando o avião estava voando ao Norte da ilha indonesiana de Sumatra. A aeronave já tinha se desviado para longe do curso que ele teria tomado para seu destino Pequim, mas ainda não tinha feito a sua vez para o Sul em direção ao Oceano Índico.
 
The aircraft experienced another such log-on request almost six hours later, though this was its seventh and final satellite handshake and is believed to have been caused by the plane running out of fuel and electrical power before apparently crashing, somewhere in the southern Indian Ocean. The other five handshakes were initiated by the satellite ground station and were not considered unusual.
 
A aeronave experimentou outra solicitação de  log-on quase seis horas mais tarde, embora este foi seu sétimo e último ‘handshake’ com o satélite e é acreditado ter sido causado pelo avião ficar sem combustível e energia elétrica antes de aparentemente se despencar, em algum lugar ao sul do Oceano Índico. Os outros cinco ‘handshakes’ foram iniciados pela estação terrestre de satélites e não foram considerados incomuns.
 
Asked whether the power interruption could have been caused by a mechanical fault, Mr Gleave said: "There are credible mechanical failures that could cause it. But you would not then fly along for hundreds of miles and disappear in the Indian Ocean."
 
Perguntado se a interrupção de energia poderia ter sido causada por uma falha mecânica, o Sr. Gleave disse: "existem falhas mecânicas críveis que causariam isso. Mas você não voaria depois ao longo de centenas de quilômetros e desapareceria no Oceano Índico".
 
Another aviation expert, Peter Marosszeky, from the University of New South Wales, agreed, saying the power interruption must have been intended by someone on board. He said the interruption would not have caused an entire power failure but would have involved a "conscious" attempt to remove power from selected systems on the plane.
 
Um outro especialista em aviação, Peter Marosszeky, da Universidade de New South Wales, concordou, dizendo que a interrupção de energia deve ter sido intencionada por alguém a bordo. Ele disse que a interrupção não teria causado uma falha de energia inteira, mas teria envolvido uma tentativa "consciente" para remover energia de sistemas selecionados no avião.
 
"It would have to be a deliberate act of turning power off on certain systems on the airplane," he said. "The aircraft has so many backup systems. Any form of power interruption is always backed up by another system.
"Teria de ser um ato deliberado de desligar a energia em determinados sistemas no avião", ele disse. "A aeronave tem vários sistemas de suporte. Qualquer forma de interrupção de energia é sempre sustentada por um outro sistema.
 
"The person doing it would have to know what they are doing. It would have to be a deliberate act to hijack or sabotage the aircraft."
"A pessoa fazendo isso teria que saber o que elas estvam fazendo. Issoteria que ser um ato deliberado para seqüestrar ou sabotar a aeronave."
 

Electrical Power

There are three individual power systems dedicated to the Primary Flight Control System, which are collectively referred to as the Flight Controls Direct Current (FCDC) power system. An FCDC Power Supply Assembly (PSA) powers each of the three power systems. Two dedicated Permanent Magnet Generators (PMG) on each engine generate AC power for the FCDC power system. Each PSA converts the PMG alternating current into 28 V DC for use by the electronic modules in the Primary Flight Control System. Alternative power sources for the PSAs include the airplane Ram Air Turbine (RAT), the 28-V DC main airplane busses, the airplane hot battery buss, and dedicated 5 Ah FCDC batteries. During flight, the PSAs draw power from the PMGs. For on-ground engines-off operation or for in-flight failures of the PMGs, the PSAs draw power from any available source.


Fault Tolerance

‘‘Fault Tolerance” is a term that is used to define the ability of any system to withstand single or multiple failures which results in either no loss of functionality or a known loss of functionality or reduced level of redundancy while maintaining the required level of safety. It does not, however, define any particular method that is used for this purpose. There are two major classes of faults that any system design must deal with. These are

 
·         A failure which results in some particular component becoming totally inoperative. An example of this would be a loss of power to some electronic component, such that it no longer performs its intended function.

·         A failure which results in some particular component remaining active, but the functionality it provides is in error. An example of this failure would be a Low Range Radio Altimeter whose output is indicating the airplane is at an altitude 500 feet above the ground when the airplane is actually 200 feet above the ground.

 


 One method that is used to address the first class of faults is the use of redundant elements. For example, there are three PFCs in the 777 Primary Flight Control System, each with three identical computing ‘‘lanes” within each PFC. This results in nine identical computing channels. Any of the three PFCs themselves can fail totally due to loss of power or some other failure which affects all three computing lanes, but the Primary Flight Control System loses no functionality. All four ACEs will continue to receive all their surface position commands from the remaining PFCs. All that is affected is the level of available redundancy.

Likewise, any single computing lane within a PFC can fail, and that PFC itself will continue to operate with no loss of functionality. The only thing that is affected is the amount of redundancy of the system.

The 777 is certified to be dispatched on a revenue flight, per the Minimum Equipment List (MEL), with two computing lanes out of the nine total (as long as they are not within the same PFC channel) for 10 days and for a single day with one total PFC channel inoperative.

Likewise, there is fault tolerance in the ACE architecture. The flight control functions are distributed among the four ACEs such that a total failure of a single ACE will leave the major functionality of the system intact. A single actuator on several of the primary control surfaces may become inoperative due to this failure, and a certain number of spoiler symmetrical panel pairs will be lost. However, the pilot flying the airplane will notice little or no difference in handling characteristics with this failure. A total ACE failure of this nature will have much the same impact to the Primary Flight Control System as that of a hydraulic system failure.

The second class of faults is one that results in erroneous operation of a specific component of the system.

The normal design practice to account for failures of this type is to have multiple elements doing the same task and their outputs voted or compared in some manner. This is sometimes referred to as a “voting plane.’’

All critical interfaces into the 777 FBW Primary Flight Control System use multiple inputs which are compared by a voting plane. For interfaces that are required to remain operable after a first failure, at least three inputs must be used. For example, there are three individual Low Range Radio Altimeter (LRRA) inputs used by the PFCs. The PFCs compare all three inputs and calculates a mid-value select on the three values; i.e., the middle value LRRA input is used in all calculations which require radio altitude. In this manner, any single failure of an LRRA that results in an erroneous value will be discarded. If a subsequent failure occurs which causes the remaining two LRRA signals to disagree by a preset amount, the PFCs will throw out both values and take appropriate action in those functions which use these data.

Additionally, a voting plane scheme is used by the PFCs on themselves. Normally, a single computing lane within a PFC channel is declared as the ‘‘master” lane, and that lane is responsible for transmitting all data onto the data busses for use by the ACEs and other airplane systems. However, all three lanes are simultaneously computing the same control laws. The outputs of all three computing lanes within a single PFC channel are compared against each other. Any failure of a lane that will cause an erroneous output from that lane will cause that lane to be condemned as ‘‘failed” by the other two lanes.

Likewise, the outputs from all three PFC channels themselves are compared. Each PFC looks at its own calculated command output for any particular actuator, and compares it with the same command that was calculated by the other two PFC channels. Each PFC channel then does a mid-value select on the three commands, and that value (whether it was the one calculated by itself or by one of the other PFC channels) is then output to the ACEs for the individual actuator commands. In this manner, it is assured that each ACE receives identical commands from each of the PFC channels.

 
 

sexta-feira, 27 de junho de 2014

MH370's New Search Area Far From Aircraft Fueled Range


Click on image to see it enlarged


"The new priority area is still focused on the seventh arc, where the aircraft last communicated with satellite. We are now shifting our attention to an area further south along the arc," Australian Deputy Prime Minister Warren Truss told reporters in Canberra.

We, professional pilots, can have this logical reasoning:

There wouldn’t be the seventh ping if there weren't the six previous pings, so researchers cannot force us to accept their calculations for the flight mileage totaling 4700 nautical miles, where they assume that the wreckage of the plane could be found.

Once the aircraft took off from Kuala Lumpur direct to waypoint IGARI, and it deflected westward (VAMPI waypoint), and from there it had its navigation to the first ping, and after this point it took heading to the South until it reaches the new search area on the seventh arc, thus totaling 4700 nautical miles of flight, but the plane was fueled for not flying  beyond 3200 nautical miles.

Why do they insist on searching the aircraft black boxes 1500 NM far from the plane fuel range?

We can think either the seven pings are INMARSAT false signals or the searchers have hidden crucial information about MH370 true flight path.