Air India Flight 171 B787-8 VT-ANB – POSSIBLE FAILURE EVENT on Slat Autogap and Slat Pregap

 

FAILURE on Slat Autogap and Slat Pregap

The slat autogap function is only available in primary mode when the slats are in the middle position [FLAPS lever set to 1 position] and the airspeed is below 225 KIAS. At a high angle of attack [seconds before the crash the plane has been seen increasing the nose pitch up], autogap fully extends the slats to increase the wing camber, thus increasing the lift and margin to stall. The slats return to the middle position after the angle of attack decreases [but the nose pitch up was kept]. The autogap trip threshold is a function of AOA, airspeed and flap position.

In the secondary mode the system is too slow to respond to an autogap request, so a pregap function exists. The slats automatically move to the fully extended position from the middle position when the flap lever is not UP and airspeed is less than 225 KIAS. The slats remain in the extended position until the flap lever is in the UP position or airspeed is above 225 KIAS.

Flaps and Slats

The flaps and slats are high lift devices that increase wing lift and decrease stall speed during takeoff, approach, and landing.

The airplane has an inboard and an outboard flap on the trailing edge of each wing, and one inboard and five outboard slats on the leading edge. A two-position Krueger flap provides a seal between the inboard slat and the engine nacelle on each wing.

In the flaps 1 position, only the slats move. Flaps 5, 15, and 20 are takeoff flap positions. Flaps 25 and 30 are landing flaps positions. Flaps 20 is used for some non-normal landing conditions.

Flap and Slat Sequencing

When the flap lever is in the UP detent, all flaps and slats are commanded to the retracted position. Moving the flap lever aft allows selection of flap detent positions 1, 5, 15, 20, 25 and 30. The flaps and slats sequence so that the slats extend first and retract last.

Starting from flaps UP, selection of flaps 1 commands the slats to move to the middle position. The flaps remain retracted.

Selection of the flaps 5, 15, and 20 positions commands the flaps to move to the position selected. The slats remain in the middle position.

Selection of flaps 25 commands the slats to move to the fully extended position. The flaps do not move.

Selection of flaps 30 commands the flaps to extend to the primary landing position.

During retraction, flap and slat sequencing is reversed.

The mechanical gate at the flaps 20 detent prevents inadvertent retraction of the flaps past the go-around flap setting. The mechanical gate at flaps 1 prevents inadvertent retraction of the slats past the middle position.

Flap and Slat Modes

There are three modes of flap and slat operation:

• primary

• secondary

⚫ alternate

In the primary mode, the flaps and slats are controlled together and positioned using center hydraulic system motors. Autogap and flap load relief operate in the primary mode.

The secondary mode is automatically engaged when any of the following conditions occur:

⚫ center hydraulic system failed, or

· flap or slat primary control failure, or

primary mode fails to move the flaps or slats to the selected position, or

• control surfaces travel at less than 50% of the normal hydraulic rate, or

⚫ uncommanded flap or slat motion is detected, or

• flap or slat disagree is detected

In the secondary mode the slats and flaps are controlled separately and can be positioned by hydraulic or electric motors. For example, if the slats hydraulic control fails, the flaps are still driven hydraulically but the slats are now powered electrically. Pilot control is through the flap lever but operation in secondary mode is limited to flaps 20 by non-normal procedures.

The three-position alternate flaps selector extends and retracts the flaps and slats. The flaps and slats extend simultaneously, but slat retraction is inhibited until the flaps are up. Alternate mode flap and slat extension is limited to the slats middle position and flaps 20. Asymmetry and uncommanded motion protection, slat autogap and pregap, and flap and slat load relief are not available in alternate mode.

The alternate mode must be manually selected. Slat and flap operation time in the secondary and alternate modes is greatly increased.

SPOOFING TCAS TRAFFIC ADVISORY & RESOLUTION ADVISORY AT RONALD REGAN NATIONAL AIRPORT (KDCA) - NO AIR TRAFFIC AROUND

UPDATED MAR 13, 2025

HELICOPTER ROUTE 4  NO MORE EXIST

UPDATED Mar 11, 2025

Many TCAS TA and RA on KDCA ARRIVAL and FINAL APPROACH, but NO INTRUDER TRAFFIC AROUND

 

The Federal Aviation Administration is investigating a multitude of Traffic Collision Avoidance System (TCAS) alerts near Reagan National Airport in Washington. Multiple aircraft from different air carriers reported the alerts Saturday while on the River Visual approach.

 

Despite these alerts, no other aircraft were detected nearby. Many aircraft received resolution advisories (RAs), directing the crew to maneuver away from a potential collision.

 

“Several flight crews inbound to Reagan Washington National Airport received onboard alerts Saturday indicating another aircraft was nearby when no other aircraft were in the area. Some of the crews executed go-arounds as a result of the alerts,” an agency spokesperson said in a statement. “The FAA is investigating why the alerts occurred.”

 

One Republic Airways crew reported an RA at around 1,200 feet, adding that “there was something diving straight onto us,” per air traffic control audio recordings. Another PSA Airlines crew said they got two traffic advisories (TA), which warn of a non-imminent collision.

DELTA 4819 CRJ-900 CRASH IN TORONTO, CANADA CYYZ - CROSS WIND GUST

 UPDATED Mar, 22 2025

PRELIMINARY REPORT

Source:

Transportation Safety Board of Canada

Air Transportation Safety Investigation A25O0021:

Preliminary Report (released 20 March 2025).

Transportation Safety Board of Canada 200 Promenade du Portage, 4th floor Gatineau QC K1A 1K8 819-994-3741; 1-800-387-3557 www.tsb.gc.ca communications@tsb.gc.ca

 

 The Transportation Safety Board of Canada (TSB)

 On 17 February 2025

 

CL-600-2D24 aircraft (CRJ-900LR) (registration N932XJ, serial number 15194) was operating as Endeavor Air flight EDV4819 from Minneapolis-Saint Paul International/Wold-Chamberlain Airport (KMSP), Minnesota, United States, to Toronto/Lester B. Pearson International Airport (CYYZ), Ontario.

 

 During the landing on Runway 23, the aircraft impacted the runway, the right wing detached, and a fire ensued. The aircraft overturned and slid down the runway inverted, coming to rest near the intersection of Runway 23 and Runway 15L. Aircraft rescue and firefighting responded, and all passengers and crew evacuated.

All times are Eastern Standard Time (Coordinated Universal Time minus 5 hours).

 

At 12:47 (EST)[ 07:47 UTC]

Flight EDV4819, IFR [Instrument Flight Rules]

FROM: Departed (KMSP) Minneapolis-St. Paul International/World-Chamberlain Airport Minnesota, United States,

TO: (CYYZ), Toronto/Lester B. Pearson International Airport Ontario, Canada

 

POB: 2 flight crew members, 2 cabin crew members, and 76 passengers on board.

The captain was seated in the left seat and was the pilot-monitoring [PIC] for the flight. The first-officer was seated in the right seat and was the pilot-flying (PF).

The crew received clearance for the instrument landing system approach to Runway 23 at CYYZ.

Weather

The aerodrome routine meteorological report for CYYZ issued at 1400 indicated the following:

• Winds from 270° true (T) at 28 knots, gusting to 35 knots

• Visibility 6 statute miles (SM) in blowing snow

• Runway visual range for Runway 24L variable between 3000 feet and more than 6000 feet with an upward trend

• Broken ceiling at 3400 feet AGL

• Temperature −9 °C and dew point −14 °C

• Altimeter setting 29.93 inches of mercury

• Remarks indicated cumulus clouds at 6 oktas

 

14:12:01 (EST) [09:12:01 UTC]

The aircraft descended through 500 feet above ground level (AGL). The aircraft’s indicated airspeed was 150 knots, its ground speed was 121 knots, and the engine thrust was indicating approximately 64% N1.3 The rate of descent was 720 fpm, and the localizer and glide slope were centered. Five seconds later, the PF disconnected the autopilot.

 

Flight controls

The flaps and slats were fully deployed at the time of the occurrence. The flap jackscrew threads were measured to be 10 inches for both the left and right inboard flap actuators (4 locations), which corresponds to 45° of flaps. Based on measurements taken from the left slat, the slats were in a 25° position.

At the time of the occurrence, the aircraft was being operated within its allowable weight-and-balance limitations. The occurrence landing weight was approximately 73 000 pounds, and there was about 6000 pounds of fuel remaining at the time of landing.

At 1412:26, while the aircraft was descending through 175 feet AGL, its indicated airspeed was 144 knots, with a ground speed of 121 knots, and a rate of descent of 672 fpm. The thrust remained at approximately 64% N1.

At 1412:30, while the aircraft was descending through 153 feet AGL, its indicated airspeed increased to 154 knots whereas the ground speed did not change appreciably, consistent with a performance-increasing wind gust. The PF pulled back the thrust levers, and as a result, over the following 5 seconds, N1 decreased from 64% to approximately 43%, where it remained until touchdown. The airspeed began to decrease.

At 1412:40 (3.6 seconds before touchdown), when the aircraft was at a height of 50 feet AGL, the indicated airspeed was 145 knots, and the ground speed was 112 knots. The rate of descent had increased to 1114 fpm. The enhanced ground proximity warning system (EGPWS) aural alert “fifty” sounded to indicate the aircraft was at 50 feet AGL, which is a standard callout.

One second later (2.6 seconds before touchdown), the EGPWS alert “sink rate” sounded, indicating a high rate of descent. The aircraft’s indicated airspeed was 136 knots, its ground speed was 111 knots, and the rate of descent had remained at about 1100 fpm. The bank angle increased to a 4.7° right bank. The engine thrust was steady at approximately 43% N1.

At 1412:42 (1.6 seconds before touchdown), the aircraft’s indicated airspeed was 136 knots, and its ground speed was 111 knots. The aircraft was slightly below the glide slope, but on the visual segment of the approach and tracking the runway centreline. The rate of descent had increased to 1072 fpm, and the bank angle was 5.9° to the right.

Less than 1 second before touchdown, the aircraft’s indicated airspeed was 134 knots, and its ground speed was 111 knots. The bank angle was 7.1° to the right, and the pitch attitude was 1° nose up. The rate of descent was recorded as 1110 fpm.

At 1412:43.6, the right main landing gear (MLG) contacted the runway. The aircraft was in a 7.5° bank to the right with 1° of nose-up pitch and 3g vertical acceleration, at a rate of descent of approximately 1098 fpm (18.3 fps).

At touchdown, the following occurred: the side-stay that is attached to the right MLG fractured, the landing gear folded into the retracted position, the wing root fractured between the fuselage and the landing gear, and the wing detached from the fuselage, releasing a cloud of jet fuel, which caught fire. The exact sequence of these events is still to be determined by further examination of the fracture surfaces.

The aircraft then began to slide along the runway. The fuselage slid down Runway 23, rolling to the right until it became inverted. A large portion of the tail, including most of the vertical stabilizer and the entire horizontal stabilizer, became detached during the roll.

The aircraft went off the right side of the runway into the snow-covered grass area and came to a rest on Runway 15L, near the intersection with Runway 23, about 75 feet beyond the right edge of Runway 23 (Figure 1). The right wing, including the right MLG, became fully detached from the aircraft and slid approximately 215 feet further along Runway 23.

Once the aircraft came to a stop, an evacuation began. All occupants evacuated the aircraft. At the time of writing this preliminary report, it has been confirmed that 21 of the 80 occupants were injured; 2 of those occupants were reported to have serious injuries.

 

Company landing standard operating procedures

The flight operations manual indicates to initiate the flare between 30 and 20 feet AGL by increasing pitch attitude as needed to slow the descent rate while continuing to reduce thrust to idle. At 20 feet, back pressure on the control column is to be maintained as necessary to hold a constant pitch angle. In addition, the manual states that the pitch attitude at touchdown should be between 3° and 8°, depending on the landing reference speed (VREF) of the aircraft. If the pitch attitude exceeds 11°, there is a risk of a tail strike.5 Also, a hard landing is defined as “[a] landing at a vertical descent rate greater than 600 ft/min when the aircraft's gross weight is less than or equal to MLW [maximum landing weight].

 

You can set this video for 720p and full screen

AMERICAN AIRLINES FLIGHT 5342 MID-AIR COLLISION MILITARY HELICOPTER - APPROACH RADAR SCREEN NOT SO PRECISE FOR TARGETS PRESENTATION

You can set this video for 720p and watch it on full screen

Above image: APPROVED FLIGHT PLAN

ATC: PAT25...PASS BEHIND...CRJ7"

PAT25 CVR: NOT RECORDED THE 'PASS BEHIND' PHRASE

Updated FEB 15, 2025 

NTSB Cleared up the ATC instruction to helicopter PA25

Ipsis Litteris

NTSB Feb. 14, 2025, NTSB Briefing Points on Mid-air Collision near DCA

Preliminary investigative information which is derived from a variety of electronic and other sources as of 1:00pm today.

• About 8:15 pm EST, the CRJ left 37,000 feet pressure altitude for an initial descent.

• About 8:30, the Blackhawk began travelling generally southbound after maneuvering near Laytonsville, Maryland. CVR audio from the Blackhawk indicated the instructor pilot was the pilot monitoring and transmitting on the radio and the pilot was the pilot flying. (ATC Radar & Blackhawk CVR)

• At 8:33:41, the Blackhawk crew requested Helicopter Route 1 to 4 to Davison Army Air Field, which the tower controller approved.

• 8:38:39, the Blackhawk reached the intersection of the DC Beltway and the Potomac River near Carderock, Maryland. After briefly turning westbound, the Blackhawk turned back to the east and began descending as it picked up helicopter route 1 over the Potomac River southeast toward downtown Washington, DC.

• At 8:39:10, Potomac Approach cleared the crew of the CRJ for the Mount Vernon Visual Runway 1 approach.

• At 8:40:46, the CRJ rolled out of a left turn established on the ILS Localizer for

Runway 1, at approximately 4,000 feet pressure altitude, 170 knots, with

landing gear up and flaps extended to 20 degrees.

• At 8:43:06, the CRJ crew made initial contact with DCA Tower. The tower

controller then asked if the crew could switch to runway 33. The CRJ crew

agreed to switch to runway 33.

• At 8:43:48, the Blackhawk was about 1.1 nautical miles (NM) west of the Key

Bridge. The pilot flying indicated they were at 300 feet. The instructor pilot

indicated they were at 400 feet. Neither pilot made a comment discussing an

altitude discrepancy. At this time, we do not know why there is a discrepancy

between the two; the investigative team is exploring this.

• At 8:44:27, as the Blackhawk approached the Key Bridge, the instructor pilot

indicated the Blackhawk was at 300 feet descending to 200 feet.

• Between 8:44:41 and 8:44:45 the CRJ crew selected 30 degrees of flaps and

then 45 degrees of flaps.

• At 8:44:49, the CRJ landing gear were down and locked. The aircraft was fully

configured for landing, approximately 6.2 NM south of the airport.

• At 8:45:27, the autopilot was disconnected and the CRJ began a shallow right

turn off of the Runway 1 localizer at a radio altitude of approximately 1,700 ft

and an airspeed of 134 kts. This occurred approximately 5.0 NM south of the

airport.

• At 8:45:30, the Blackhawk passed over the Memorial Bridge. The instructor

pilot told the pilot flying that they were at 300 feet and needed to descend.

The pilot flying said they would descend to 200 feet.

• At 8:45:58, the Blackhawk then crossed over the Washington Tidal Basin and

followed the Washington Channel consistent with Helicopter Route 1.

• It is now approximately two minutes before the collision.

• At 8:46:01, a radio transmission from the tower was audible on the CRJ CVR

informing the Blackhawk that traffic just south of the Wilson Bridge was a CRJ

at 1200 feet circling to runway 33.

3Feb. 14, 2025, NTSB Briefing Points on Mid-air Collision near DCA

• CVR data from the Blackhawk indicated that the portion of the transmission

stating the CRJ was “circling” may not have been received by the Blackhawk

crew. We hear the word “circling” in ATC communications, but we do not hear

the word “circling on the CVR of the Blackhawk. The Recorders Group is

evaluating this.

• At 8:46:08, the Blackhawk crew responded they had the traffic in sight and

requested visual separation which was approved by DCA Tower.

• At 8:46:29, the CRJ crew received a 1000-foot automated callout.

• At 8:46:47, DCA tower cleared other jet traffic on Runway 1 for immediate

departure with no delay.

• At 8:47:27, or 32 seconds before impact, the Blackhawk passed the southern

tip of Hains Point.

• A second later, the CRJ began a left roll to turn to final on Runway 33. The CRJ

was at a radio altitude of 516 ft and 133 kts.

• At 8:47:29, the CRJ crew received a 500-foot automated callout.

• At 8:47:39, or 20 seconds before impact, a radio transmission from the tower

was audible on both CVRs asking the Blackhawk crew if the CRJ was in sight.

Audible in the ATC radio transmission was a Conflict Alert in the background.

• At 8:47:40, the CRJ crew received an automated traffic advisory from the TCAS

system stating “Traffic, Traffic.” TCAS is the Traffic Alert and Collision Avoidance

System on the CRJ.

• At 8:47:42, or 17 seconds before impact, a radio transmission from the tower

was audible on both CVRs directing the Blackhawk to pass behind the CRJ.

CVR data from the Blackhawk indicated that the portion of the transmission

that stated “pass behind the” may not have been received by the Blackhawk

crew. Transmission was stepped on by a 0.8 second mic key from the

Blackhawk. The Blackhawk was keying the mic to communicate with ATC.

• In response, at 8:47:44, the Blackhawk crew indicated that traffic was in sight

and requested visual separation which was approved by DCA Tower. The

instructor pilot then told the pilot flying they believed ATC was asking for the

helicopter to move left toward the east bank of the Potomac.

4Feb. 14, 2025, NTSB Briefing Points on Mid-air Collision near DCA

• At 8:47:52, or 7 seconds before impact, the CRJ rolled out on final for runway 33. The CRJ was at a radio altitude of 344 ft, 143 kts.

• At 8:47:58, or 1 second before impact, the CRJ began to increase its pitch, reaching about 9 degrees nose up at the time of collision. FDR data showed the CRJ elevators were deflected near their maximum nose up travel.

• The last radio altitude recorded for the CRJ was 313 ft and was recorded two seconds prior to the collision. The CRJ pitch at this time was, again, 9 degrees nose up, and roll was 11 degrees left wing down. The CRJ was descending at 448 feet per minute.

• The radio altitude of the Blackhawk at the time of the collision was 278 feet and had been steady for the previous 5 seconds. The Blackhawk pitch at the time of the collision was about a half degree nose up with a left roll of 1.6 degrees. Examination of wreckage will assist in determination of the exact angle of the collision.

• We are confident that the radio altitude of the Black Hawk at the time of the collision was 278 feet. I want to caution this does not mean this is what the Black Hawk crew was seeing on the barometric altimeters in the cockpit.

• We are seeing conflicting information in the data, which is why we aren’t releasing altitude for the Blackhawk’s route.

INSIDE ALL AIR TRAFFIC CONTROL TOWER THERE IS AT LEAST A RECORDER

• The CRJ’s cockpit voice recorder has now been downloaded and read out. All times listed in Eastern Standard Time —
• 20:45:27: CRJ Autopilot off
• 20:46:01: ATC makes PAT25 aware of CRJ south of the Wilson Bridge
• 20:46:29: 1000’ call out on CRJ
• 20:47:29: 500’ call out on CRJ
• 20:47:39: ATC asks if PAT25 has the CRJ in sight
• 20:47:40: TRAFFIC TRAFFIC aural alert sounds
• 20:47:42: DCA Tower directs PAT25 to pass behind the CRJ
• 20:47:58: CRJ crew has verbal reaction and airplane begins to increase its pitch
• 20:47:59: Sounds of impact
• There were 5 air traffic controllers in the DCA tower at the time of the accident
• 1 Local controller working fixed wing and helicopter traffic
• 1 Ground controller
• 1 local assistant controller
• 1 Supervisor
• 1 Supervisor in training

 

• The CRJ’s cockpit voice recorder has now been downloaded and read out. All times listed in Eastern Standard Time —
• 20:45:27: CRJ Autopilot off [Piloto Automático do avião foi desligado]
• 20:46:01: ATC makes PAT25 aware of CRJ south of the Wilson Bridge [Controlador de Tráfego Aéreo alerta o piloto do helicóptero acerca do avião ao sul da ponte Wilson]
• 20:46:29: 1000’ call out on CRJ [o Sistema de automático de alerta de altitude do avião anuncia que a aeronave está 1000 pés acima da superfície da água]
• 20:47:29: 500’ call out on CRJ [o EGPWS alerta que o avião está 500 pés acima da superfície da água]
• 20:47:39: ATC asks if PAT25 has the CRJ in sight [o Controlador de Tráfego Aéreo pergunta ao piloto do helicóptero se ele tem na visão dele o avião]
• 20:47:40: TRAFFIC TRAFFIC aural alert sounds [o Sistema de Alerta de Colisão entre Aeronaves dispara o anúncio TRÁFEGO, TRÁFEGO]
• 20:47:42: DCA Tower directs PAT25 to pass behind the CRJ [o Controlador de Tráfego Aéreo instrui o helicóptero para passar por trás do avião]
• 20:47:58: CRJ crew has verbal reaction and airplane begins to increase its pitch [o piloto do avião reage verbalmente e inicia o aumento de inclinação do nariz do avião para cima]
• 20:47:59: Sounds of impact [ouve-se o ruido da colisão das duas aeronaves]
•  
• There were 5 air traffic controllers in the DCA tower at the time of the accident
• Havia 5 Controladores de Tráfego Aéreo na hora do acidente:

 

• 1 Local controller working fixed wing and helicopter traffic

[Um Controlador local trabalhando no tráfego de aeronave com asa fixa(avião) e helicóptero].

• 1 Ground controller

[Um Controlador de tráfego no solo]

• 1 local assistant controller

[Um Assistente de Controlador]

• 1 Supervisor

[Um Supervisor]

• 1 Supervisor in training

[Um Supervisor em treinamento]

According to an Army report, the service began issuing night-vision devices to its aviators in 1985 and has continually acquired goggles that allow pilots and aircrew to see more clearly and with better depth perception at night ever since.

Pete Hegseth, secretary of defense, said the Army crew members involved in Wednesday’s crash were performing a required annual night training and that they “did have night-vision goggles.”

Recent Army-wide standardization inspections and accident investigations have revealed deficiencies in maintenance and use of night vision goggles (NVGs) and the Aviator’s Night Vision Imaging System (ANVIS). The purpose of this article is to clarify requirements for modification, inspection, and use of AN/PVS-5 series NVGs and the ANVIS-6.

 

AN/PVS-5 series NVGs Modification.  Only two modifications are authorized for ANI PVS-5 series NVGs used in aviation operations. One is the modified faceplate

(MFP) described in the U.S. Army Aviation Center booklet: AN/PVS-5, 5A Night Vision Goggle Aviator Modifications, dated 10 Jun 83.

The other modification authorized for AN/PVS-5 NVGs in aviation use is the GX-5 flip-up described in an April 1987 booklet published by the Aviation Life Support Equipment Project Manager’s Office, Aviation Systems Command (AVSCOM).

Runway 33 and Runway 04 CLOSED

Above image: OFFICIAL HELICOPTER CORRIDORS in hard blue; APPROVED Flight Plan in magenta; MAXIMUM ALTITUDE in red circle.

 

The Air Traffic Controller's radar screen demonstrates that there is NO PRECISION for each aircraft geographical position in the target presentation on the radar screen. The targets are shown as if the helicopter had already passed behind the CRJ7 plane. In conclusion, the ATC see the target in FALSE position. There is an ERROR between the target shown on radar screen and the real aircraft position.

In the next second, the plane descends 300 feet and collides with the helicopter.

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.