terça-feira, 6 de novembro de 2007

Airbus 320 - RESOLUTION no TCAS - vôo TAM










O chefe do CINDACTA -1 ( Brasília ) disse em entrevista para a imprensa que o fato dos radares do CINDACTA não terem detectado a outra aeronave que fez o avião da TAM fazer manobra evasiva no vôo de Palmas, TO para Brasília, DF, era algo impossível de ter acontecido, pois segundo ele não haveria condições do radar detectar somente um avião.

A insídia do chefe do CINDACTA-1 deixou os pilotos do avião da TAM como possívelmente tendo inventado o incidente aéreo.

Não é VERDADE o que o coronel disse.

Esqueceu-se o coronel da FAB que os pilotos somente fazem a manobra evasiva DEPOIS de receberem os alertas VISUAIS e SONOROS do sistema TCAS.

Está reproduzido abaixo a parte do Flight Crew Operation Manual do Airbus 320, provando que os pilotos fizeram a manobra corretamente e NÃO se tratou, como o chefe do CINDACTA-1, disse que os pilotos já estão tão temerosos e qualquer pequeno alerta se assutam e fazem manobras desnecessárias.

Tenho tal declaração como um total falta de conhecimento das normas que regem a aviação civil em se tratando da apresentação RESOLUTION.

FCOM Airbus 320

The TCAS (Traffic alert and Collision Avoidance System) :

Detects any aircraft, equipped with transponders, flying in its vicinity; Displays potential and predicted collision targets; Issues vertical orders to avoid conflict.

The TCAS is normally independent of the ground-based air traffic control system.

The TCAS detection capability is limited to intruders flying within a maximum range of
30-40 NM (depending on aircraft configuration and external conditions), and within a maximum altitude range of 9900 feet (above and below the threatened aircraft).

MAIN COMPONENTS

The system includes :
- a single channel TCAS computer two TCAS antennas two mode S ATC transponders, one active the other in standby.

These transponders allow :
- interface between the ATC / TCAS control panel and the TCAS computer communication between the aircraft and intruders equipped with a TCAS system an ATC /TCAS control panel.

PRINCIPLE

The TCAS interrogates transponder of intruders. From the transponder replies, the TCAS determines for each intruder :
- its relative bearing its range and closure rate

- its relative altitude if available (ATC mode C or S)

Then the TCAS computes the intruder trajectory, the Closest Point of Approach (CPA) and the estimated time (TAU) before reaching the CPA.

Each time the relative position of the intruder presents a collision threat, aural and visual advisories are triggered.

TCAS optimizes vertical orders to ensure a sufficient trajectory separation and a minimal vertical speed variation considering all intruders.

INTRUDER CLASSIFICATION

The intruders are classified in four levels :

TCAS MODES
The TCAS has 2 modes of operation :

- TA/RA: This mode allows the display of all intruders.

- TA: Can be selected by : the crew, on the ATC/TCAS panel, in case of aircraft degraded performance (engine failure, landing gear extended) or when operating near closely spaced parallel runways, or automatically, when the following messages are triggered :

- windshear (aural alert) stall

- GPWS messages Consequently :

- all RA are inhibited and converted into TA

TA threshold is set to TAU <= 20 seconds independent of aircraft altitude. No vertical speed advisories are indicated on the PFDs

- TA ONLY is displayed on the NDs If windshear, stall or GPWS messages are triggered, all the TCAS aural messages are suppressed.

ADVISORY INHIBITION
Some advisories are inhibited depending on the aircraft altitude:
- all intruders flying below 380 feet AGL when the own aircraft altitude is below 1700 feet AGL.
- all TA aural messages and all RAs below 1100 feet in climb and 900 feet in descent. In this case, the RAs are converted into TAs. "Descend" type advisory below 1200 feet AGL at takeoff or 1000 feet AGL in approach. "Increase Descent" RA below 1450 feet.

ND INDICATIONS (ND=Navigation Display)
The traffic is displayed in all ROSE modes and ARC mode when 10, 20 or 40 NM range is selected.

Only the 8 most threatening intruders are displayed. Veja Imagem.

TCAS MESSAGES

1 Mode and range messages

Following messages can be displayed to draw pilot's attention :

TCAS : REDUCE RANGE:

displayed when a TA or RA is detected and ND range above 40 NM

TCAS : CHANGE MODE :

displayed when a TA or RA is detected and ND mode is PLAN. Displayed amber or red depending on the advisory level (TA or RA).Flash 9 seconds then remain steady.

2 TCAS operation messages

- TCAS: displayed red in case of TCAS internal failure.Flashes 9 seconds then remains steady.

- TA ONLY : displayed white when selected by the crew.

PFD INDICATIONS (PFD=Primary Flight Display)

In case of RA detection, the PFD presents vertical orders on the vertical speed scale. The vertical speed scale background is normally grey, but may be partially replaced by green and/or red areas.

1 Red area Indicates the vertical speed range, where the risk of conflict is high.

2 Green area Indicates the recommended vertical speed range.

Note :
The aircraft can also fly in the grey vertical speed range without the risk of conflict (preventive RA).

The color of the vertical speed needle and the digits corresponds to the appropriate area.

3 TCAS message

- Appears in red when TCAS cannot deliver RA data, or in case of TCAS internal failure.

AURAL MESSAGES

TA/RA detection is associated with the following messages :

TRAFFIC TRAFFIC: only in case of TA detection.

CLIMB CLIMB CLIMB : climb at the vertical speed indicated by the green area on PFD.

CLIMB CROSSING CLIMB (twice) : same as above. Indicates that you will cross through the intruder altitude.

INCREASE CLIMB (twice) : triggered after CLIMB message if vertical speed not sufficient to achieve safe vertical separation.

REDUCE CLIMB (twice): reduce vertical speed to that indicated on PFD green area.

DESCEND DESCEND DESCEND: descend at the vertical speed indicated by the green area on PFD.

DESCEND CROSSING DESCEND (twice): same as above. Indicates that you will cross through the intruder altitude.

INCREASE DESCEND (twice): triggered after DESCEND message if vertical speed not sufficient to achieve safe vertical separation.

REDUCE DESCEND (twice): reduce vertical speed to that indicated on the PFD green area.

CLIMB CLIMB NOW (twice): triggered after DESCEND message if the intruder trajectory has changed.

DESCEND DESCEND NOW (twice): triggered after CLIMB message if the intruder trajectory has changed.

MONITOR VERTICAL SPEED (twice): ensure that vertical speed remains outside the red area.Triggered only when leaving a previous RA.

CLEAR OF CONFLICT: range is increasing and separation is adequate.Return to assigned clearance.

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