BEFORE FULL FLAPS
quinta-feira, 10 de setembro de 2026
sábado, 12 de julho de 2025
AIR INDIA FLIGHT 171 - AFTER ENGINE STARTING IN-FLIGH THERE WAS A MAYDAY CALL
BOEING 787-9 AUTOSTART
Both engines are normally started at the same time, unless the outside air temperature is below 41°F (5°C).
FROM THE PRELIMINARY REPORT
As per the EAFR data both engines N2 values passed below minimum idle speed, and the RAT hydraulic pump began supplying hydraulic power at about 08:08:47 UTC.
RAT in extended position
As per the EAFR, the Engine 1 fuel cutoff switch transitioned from CUTOFF to RUN at about 08:08:52 UTC. The APU Inlet Door began opening at about 08:08:54 UTC, consistent with the APU Auto Start logic. Thereafter at 08:08:56 UTC the Engine 2 fuel cutoff switch also transitions from CUTOFF to RUN. When fuel control switches are moved from CUTOFF to RUN while the aircraft is inflight, each engines full authority dual engine control (FADEC) automatically manages a relight and thrust recovery sequence of ignition and fuel introduction.
The EGT was observed to be rising for both engines indicating relight. Engine 1’s core deceleration stopped, reversed and started to progress to recovery. Engine 2 was able to relight but could not arrest core speed deceleration and re-introduced fuel repeatedly to increase core speed acceleration and recovery. The EAFR recording stopped at 08:09:11 UTC
At about 08:09:05 UTC, one of the pilots transmitted “MAYDAY MAYDAY MAYDAY”. The ATCO enquired about the call sign. ATCO did not get any response but observed the aircraft crashing outside the airport boundary and activated the emergency response.
To move any FUEL flow control switch from RUN position to CUT-OFF position requires PULLING the switch BACKWARD to pass it over the safety detent and, put it down on CUT-OFF position. It is very hard accidentally the switch moves to CUT OFF position.
Operation illustration for LAYMEN better understanding
Considering the MAYDAY call a consequence of a very stressful situation on flightdeck.
So, the first thing the pilots
had to pay attention it was the engine parameters out of standard and
secondarily, a pilot had acknowledged an abnormal engine.
Following that, the other pilot
has perceived an engine having been shut down by his colleague, who denied to
have shut down the engine.
We, out of the cockpit, must
accept the condition for shutting down an engine. The pilot needs to pull the
FUEL switch up (back) to overtake the safety detent and, bring it to OFF
position, so the FUEL flow will be cut to the engine.
The FUEL switch has no condition
to jump for itself over the safety detent.
Now we have two possibilities:
1. A pilot mistakenly moved manually the FUEL switch to OFF position. But he denied it.
2. The FUEL switch had lost electric power to keep the fuel flow function (at the RUN position) feeding the engine.
NOTE: There is a COMMON MOTOR STARTER CONTROLLER
The Common Motor Starter Controller or CMSC, supplies variable frequency and variable AC voltage to airplane systems that need a high voltage to operate such as the Cabin Air Compressor and the Electric Motor Pump. Because the CMSC's can get very hot, they are cooled via the Power Electronic Cooling System (PECS).
Click on the image to see isolated
In-Flight Start
In-flight
start envelope information
is displayed on the EICAS display when an engine is
not running in flight (N2
RPM below idle RPM) or when an engine is
shut down in flight and the respective
engine fire switch is not pulled.
The in-flight start envelope indicates the airspeed range necessary to ensure
an in-flight start at the current flight level. If the current flight level is
above the maximum start altitude, the maximum start altitude and respective
airspeed range are displayed.
Secondary
engine indications are automatically displayed in flight when an engine is not running (N2 RPM is below idle with
corresponding FUEL CONTROL switch in RUN)
or when a FUEL CONTROL switch is moved to CUTOFF.
A starter assist indication (X-START) is displayed below the N2 indication if
airspeed is below that recommended for a windmilling start. For in- flight
starts, autostart makes continuous start attempts until the engine either
starts or the pilot aborts the start attempt by positioning the FUEL CONTROL
switch to CUTOFF (and positioning the START switch to NORM if it was a starter
assisted attempt).
During the windmilling in-flight start, the EEC monitors engine parameters to provide the best fuel schedule to ensure the shortest possible start time. (Refer to Engine In-Flight Start, QRH, Non-Normal Checklists Chapter 7, for the in-flight engine start procedure.)
NOTE: There is a COMMON MOTOR STARTER CONTROLLER
The Common Motor Starter Controller or CMSC, supplies variable frequency and variable AC voltage to airplane systems that need a high voltage to operate such as the Cabin Air Compressor and the Electric Motor Pump. Because the CMSC's can get very hot, they are cooled via the Power Electronic Cooling System (PECS).
Engine start (Dynamic)
Once all doors and hatches are closed, external cables and pipes have been removed and the APU is running, we're ready to push back from the gate and start our engines.
Both engines are normally started at the same time, unless the outside air temperature is below 41°F (5°C).
On other aircraft types, the engines require high pressure air from the APU to turn the starter in the engine. This requires a lot of power from the APU and is also quite noisy. On the 787, the engine start is entirely electrical.
Power is drawn from the APU and feeds the VFSGs in the engines. If you remember from earlier, these fist act as starter motors. The starter motor starts the turn the turbines in the middle of the engine. These in turn start to turn the forward stages of the engine. Once there is enough airflow through the engine, and the fuel is igniting, there is enough energy to continue running itself.
The electrical system during an engine start. L1 and L2 are in generator mode whilst R1 and R2 are acting as starters. The APU is still providing power to the aircraft systems.
After start
Once the engine is running, the VFSGs stop acting as starter motors and revert to acting as generators. As these generators are the preferred power source, they automatically take over the running of the electrical systems from the APU, which can then be switched off. The aircraft is now in the desired configuration for flight, with the 4 VFSGs in both engines providing all the power the aircraft needs.
As the aircraft moves away toward the runway, another electrically powered system is used — the brakes. On other aircraft types, the brakes are powered by the hydraulics system. This requires extra pipe work and the associated weight that goes with that. Hydraulically powered brake units can also be time consuming to replace.
By having electric brakes, the 787 is able to reduce the weight of the hydraulics system and it also makes it easier to change brake units. "Plug in and play" brakes are far quicker to change, keeping maintenance costs down and reducing flight delays.
In-flight
Another system which is powered electrically on the 787 is the anti-ice system. As aircraft fly though clouds in cold temperatures, ice can build up along the leading edge of the wing. As this reduces the efficiency of the wing, we need to get rid of this.
How pilots keep you safe while flying through strong winds
Other aircraft types use hot air from the engines to melt it. On the 787, we have electrically powered pads along the leading edge which heat up to melt the ice.
Not only does this keep more power in the engines, but it also reduces the drag created as the hot air leaves the structure of the wing. A double win for fuel savings.
Engine generators
Two Starter/Generators 235 Vac (L1-L2-R1-R2)
- Each engine, two starter/Generators are directly connected to the Engine gear box, producing variable frequency power proportional to the Engine rotor speed.
- Both engine starters are used for engine start, but nevertheless the engine may be started with only one generator. The start will be slower than the normal start.
- Power for engine start may be provided by the APU, opposite engine generators or external power.
- Both generators on each side will provide a variable frequency of 235 Vac to the AFT E/E bay, were power is distributed. Four main buses (L1-L2-R1-R2) each powered by its respective generator line. Automatic protection ensures that only one source is applied to the main bus at a time.
- Each generator has a drive disconnect mechanism that allows the generator to be mechanically disconnected from the engine. Depending on the fault condition, can be disconnected manually or automatically. (DRIVE DISC), once disconnected cannot be reconnected.
The Preliminary Report brought the answer, the landing gear lever was not moved to the UP position after lift off.
The flap handle assembly (fig.11) sustained significant thermal damage. The handle was found to be firmly seated in the 5-degree flap position, consistent with a normal takeoff flap setting. The position was also confirmed from the EAFR data. The landing gear lever was in “DOWN” position. (fig.12)
The thrust lever quadrant sustained significant thermal damage. Both thrust levers were found near the aft (idle) position. However, the EAFR data revealed that the thrust levers remained forward (takeoff thrust) until the impact. Both fuel control switch were found in the “RUN” position. (fig.13) The reverser levers were bent but were in the “stowed” position. The wiring from the TO/GA switches and autothrottle disconnect switches were visible, but heavily damaged.
Click on the image to magnify it (isolated)
In-Air Rat only Mode (Standby Power)
Is active with the loss of all electrical power to the Captain’s & First officers flight instruments, in that case the RAT will energize the captains flight instruments with some essential equipment including flight controls, navigation and communications.
Energized equipment by the RAT are as follows.
Captains inboard & outboard DU’s, lower DU,MCP, PFC, ECL, FMC limited operation, Autopilot limited operation, Autoflight system, Captain’s & First officer’s ACP’s and the flight interphone, LEFT( VHF/TCP/DSP/MFK/CCD/CCR), LEFT & RIGHT (IRU/AHRU/INR), Centre pitot heat, Engine/APU fire detection and miscellaneous lighting.
INOP systems include TAT, Autothrottle, LNAV/VNAV, FMC predictions and thrust limits, TAP, Flaps & Slats, Stabilizer trim, Packs, HUD’s, HF, SATCOM, TCAS, GPWS, Transponder, WX radar, External lighting, Wipes, and Window heat.
quinta-feira, 12 de junho de 2025
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.
sexta-feira, 7 de março de 2025
SPOOFING TCAS TRAFFIC ADVISORY & RESOLUTION ADVISORY AT RONALD REGAN NATIONAL AIRPORT (KDCA) - NO AIR 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.
terça-feira, 18 de fevereiro de 2025
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].
sexta-feira, 31 de janeiro de 2025
AMERICAN AIRLINES FLIGHT 5342 MID-AIR COLLISION MILITARY HELICOPTER - APPROACH RADAR SCREEN NOT SO PRECISE FOR TARGETS PRESENTATION
ATC: PAT25...PASS BEHIND...CRJ7"
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.
- 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.
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).
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.


