JEJU AIR 7C2216 CVR and FDR LAST 4 MINUTES RECORDINGS OUT - POSSIBLE EVENT - CROSS BUS TIE RELAY NOT OPENED

 

On the very moment the GLIDE SLOPE is intercepted the CROSS BUS TIE RELAY automatically opens.

 The CROSS BUS TIE RELAY opens to isolate the navigation receivers and Flight Control Computers. The RELAY opening prevents all approach phase data be removed from FDR because of only one electrical failure.

The CROSS BUS TIE RELAY also opens when the BUS TRANSFER switch is moved to OFF.

 If NORMAL power sources to DC BUS fail, the emergency source of DC power is the batteries.

 If both generators come disconnected from the BUS TRANSFER BUS, the AUTOPILOT disengages and it can't be ENGAGED up to the generators are available. The plane must be piloted MANUALLY. It will be hard work.

With no electrical source available, the batteries can supply electrical power up to minimum of 60 minutes.

UPDATED UPON PRELIMINARY REPORT Jan 27, 2025

Cockpit Voice Recorder

The cockpit voice recorder uses four independent channels to record flight deck audio for 30 minutes or 120 minutes. Recordings older than 30 or 120 minutes are automatically erased. One channel records flight deck area conversation using the area microphone. The other channels record individual ACP output (headset) audio and transmissions for the pilots and observer. (Aircraft fit dependent) The RIPS (Recorder Independent Power Supply) provides power to the cockpit voice recorder for 10 minutes after aircraft power is interrupted either by normal shutdown or by any other loss of power. Normal power supply 115V TRANSFER BUS 2 and 28 V from DC BUS 2.

VOICE RECORDER Switch (when fitted):

AUTO - powers the cockpit voice recorder from first engine start until 5 minutes after last engine shutdown

ON - powers the cockpit voice recorder until the first engine start, then trips the switch to AUTO. On aircraft with no switch the voice recorder is active anytime 115V AC is applied to airplane.

As soon as the aircraft has intercepted the LOCALIZER course, following that the pilot attention will be on GLIDE SLOPE interception.

BATTERY POWER

Emergency source for:

- Static Inverter/AC Standby Bus

- DC Standby Bus

- Battery Bus

- Hot Battery Bus

- Switched Hot Battery Bus

The Static Inverter changes 24 DC power to 115 AC power for the AC STANDBY BUS.

The HOT BATTERY BUS is always connected to the battery, and all its components operate as long as the battery voltage is above a minimum value.

The pilot must move the BUS TRANSFER switch to OFF position and turn off the HIDRAULICS ELECTRIC PUMPS.

After trying to restore the generators, if both GEN OFF BUS (L & R) lights stay ON, the pilot must land the plane ASAP.

The CVR is a customer option, popular choices are the L-3 FA2100 and Honeywell 980-6020/980-6022. Both manufacturers offer these with a crash survivable memory unit (CSMU) for protection of the solid state voice recording memory. The capacity of the CSMU is a customer option, legally the state of registration may only need 30 minutes. The CSMU retains the most recent 30 or 120 minutes of audio, digital, and timing information. Unless you know the part number of the CVR installed, you will not know if it is a 30 minute or 120 minutes capacity, they look identical.

Another customer option is the overhead "Voice Recorder" switch, with ON and AUTO positions. If it has that switch it should shut down 5 minutes after the engines are shut down (based upon oil pressure), if it does not have that optional auto switch it can record whenever 115V is supplied.

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.