Boeing 737 Airplanes with Collins Aerospace SVO-730 Rudder Rollout Guidance Actuators - NTSB URGENT

 

The National Transportation Safety Board (NTSB) is providing the following information to urge The Boeing Company and the Federal Aviation Administration (FAA) to take immediate action on the safety recommendations in this report concerning the potential for a jammed or restricted rudder control system on certain Boeing 737 airplanes. We identified these issues during our ongoing investigation of the rudder pedal anomaly involving a Boeing 737-8, N47280, while landing at Newark Liberty International Airport (EWR), Newark, New Jersey, on February 6, 2024.

 Federal Aviation Administration:

  Determine whether Collins Aerospace SVO-730 rudder rollout guidance actuators with incorrectly assembled bearings should be removed from Boeing 737NG and 737MAX airplanes and, if so, direct US operators to remove the actuators until acceptable replacement actuators become available for installation. (A-24-29) (Urgent)

If you determine the Collins Aerospace SVO-730 rudder rollout guidance actuators with incorrectly assembled bearings should be removed, notify international regulators that oversee operators of Boeing 737 airplanes about the safety issues involving the SVO-730 rudder rollout guidance actuator and encourage them to require the removal of actuators with incorrectly assembled bearings from 737NG and 737MAX airplanes until an acceptable replacement actuator becomes available for installation. (A-24-30) (Urgent)

 September 26, 2024

Aviation Investigation Report AIR-24-06

 Background and Analysis

On February 6, 2024, about 1555 eastern standard time, the flight crew of United Airlines flight 1539, a Boeing 737-8, N47280, experienced a rudder pedal.

 anomaly while landing at EWR.1 In a postincident statement, the captain reported that, during the landing rollout, the rudder pedals were “stuck” in their neutral position and did not move in response to the “normal” application of foot pressure to maintain alignment with the runway centerline.2 The flight was operating under the provisions of Title 14 Code of Federal Regulations Part 121 as a scheduled international passenger flight from Lynden Pindling International Airport, Nassau, Bahamas, to EWR.3

According to data derived from the flight data recorder, the flight crew applied approximately 32 pounds of force to the rudder pedals before touchdown which yielded no discernible effect on the rudder position or heading.4 The flight crew attempted to clear the jammed rudder controls immediately after touchdown, applying approximately 75 pounds of force to the rudder pedals when the airspeed was about 120 knots, again with no effect on the rudder position or heading.

With the airplane’s airspeed continuing to decrease during rollout, the flight crew applied approximately 42 pounds of force to the pedals, but the jam persisted. The captain elected instead to use the nosewheel steering tiller as the airplane slowed to a safe taxi speed. The captain stated that, after the airplane entered the assigned taxiway, he asked the first officer to check the rudder pedals on his side of the flight deck, and the first officer indicated that the same anomaly was occurring.

Data derived from the flight data recorder indicate that shortly after, with the airplane traveling at a groundspeed of less than 20 knots, the flight crew applied approximately 59 pounds of force on the rudder pedals, and the rudder pedals and rudder surface began to operate normally. The airplane taxied to the gate without further incident, and all airplane occupants (2 flight crewmembers, 4 cabin crewmembers, and 155 passengers) deplaned without any injuries or damage to the airplane.

United Airlines received the incident airplane from Boeing on February 20, 2023. The airplane was equipped with a Collins Aerospace SVO-730 rudder rollout guidance actuator, which was electrically disabled based on the operator’s delivery requirements for the autoflight system.5 Although the actuator was disabled, it remained mechanically connected to the upper portion of the airplane’s aft rudder input torque tube by the actuator’s output crank arm and a pushrod, as shown in figure 1.

 The Collins SVO-730 rudder rollout guidance actuator is installed only on Boeing 737NG and 737MAX airplanes equipped for category IIIB operations. (The incident 737-8 was a MAX variant.) United Airlines does not require category IIIB capability for its Boeing 737 fleet. According to FAA Advisory Circular 120-28D, category IIIB operations involve a precision instrument approach and landing with no decision height and a runway visual range less than 700 ft but not less than 150 ft.

6 Pilot control of the Boeing 737-8 rudder is transmitted in a closed-loop system from the pilots’ rudder pedals in the cockpit, through a single cable system, an aft rudder quadrant, and a pedal force transducer, to the aft rudder input torque tube in the vertical stabilizer. Rotation of the torque tube provides the command inputs to the main and standby rudder power control units to move the rudder surface.

VOEPASS 2283 [PASSAREDO CALLSIGN] PRELIMINARY REPORT - LOSS OF CONTROL IN-FLIGHT (LOC-I)

 

You can set this video for full screen and resolution 720p

SOURCE: CENIPA

LOC-I LOSS OF CONTROL IN-FLIGHT

Date: 9 August 2024

(UTC): 9 August 2024

Time: 16:22

City: VINHEDO - SÄO PAULO - BRASIL

Aerodrome: OUTSIDE THE AERODROME

Local: RESIDENTIAL AREA OF THE CITY

Damage to third

parties: YES

Injuries Function on Board Quantity

FATAL CREW 4

FATAL PASSENGERS 58

 

History

 

At 14:58 UTC, the aircraft took off from SBCA (Coronel Adalberto Mendes da Silva Airport, Cascavel, State of Paraná), bound for SBGR (Guarulhos - Governador André Franco Montoro - Airport, Guarulhos, State Of SOO Paulo) on a public regular passenger transport flight with 04 crew and 58 passengers on board. With the aircraft flying along the route, and after encountering icing conditions, control Of the aircraft was lost and it crashed into the ground.

 

Aircraft Involved

Registration marks: PSVPB

Location of latest takeoff: SBCA - ADALBERTO MENDES DA SILVA

Location of intended landing: SBGR - GOVERNADOR ANDRÉ FRANCO MONTORO

Type of operation: REGULAR

Phase of flight: CRUISE

Aircraft damage: DESTROYED

 

Sequence of events

Based on the information collected at the initial field Investigation, as well as recordings from the Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR), the Investigation Committee identified the sequence of events preceding the aircraft's collision with the ground. The time reference utilized is UTC (Universal Time Coordinated).

• 14:58:05 - the aircraft initiated takeoff from the runway 15 of SBCA, with 58 passengers and 04 crew on board;

• - the PROPELLER ANTI-ICING 1 and 2 were turned on;

• 15:14:56 - the Electronic Ice Detector connected to the Centralized Crew Alert System (CCAS) emitted an alert signal upon passing FL130;

• - the AIRFRAME DE-ICING was turned on;

• 15:15:42 - a single chime was heard in the cockpit. Subsequently, the crew commented on the occurrence of an AIRFRAME DE-ICING Fault, and that they would turn it Off;

• 151549 - the AIRFRAME DE-ICING was turned off,

- the Electronic Ice Detector ceased emitting the alert signal.

• 1516125

• 1517:08

- the Electronic Ice Detector emitted an alert signal.

- the Electronic Ice Detector stopped emitting the alert signal;

- the Electronic Ice Detector emitted an alert signal;

- the Electronic Ice Detector stopped emitting the alert signal.

- the Electronic Ice Detector emitted an alert signal;

- the Electronic Ice Detector stopped emitting the alert signal;

- the Electronic Ice Detector emitted an alert signal;

- the SIC (pilot Second in Command) made radio contact with the airline's operational dispatcher at

Guarulhos airport, for coordination of the aircraft arrival;

• - At the same time of the SIC's coordination with the operational dispatcher, a flight attendant called

over the intercom. The SIC asked her to hold on moment and continued speaking with the dispatcher,

• - the Electronic Ice Detector stopped emitting the alert signal. At this time, the SIC was asking the

flight attendant for information that would be passed to the operational dispatcher;

• 16:17:32 - the Electronic Ice Detector emitted an alert signal; at this time, the PIC was informing the passengers about the SBGR local conditions and estimated time of landing,

• 16:17:41- the AIRFRAME DE-ICING was turned on;

• 16:18:41 - at a speed of 191 kt., the CRUISE SPEED LOW alert was triggered. Concomitantly, the SIC was about to finish relaying some information to the operational dispatcher;

• 16:18:47 - the PIC started the briefing relative to the approach for landing in SBGR. Concomitantly, APP-SP made a radio call, and instructed him to change to frequency 123.25MHz;

• 16:18:55 — a single chime was heard in the cockpit. At this time, the communication with APP-SP was taking place;

• - the AIRFRAME DE-ICING was turned off;

• 16:19:16 - the crew made a call to APP-SP (Sao Paulo Approach Control) on the frequency 123.25 MHz;

• 16:19:19 - APP-SP requested the PS-VPB aircraft to maintain FL170 due to traffic;

• 16:19:23 - the crew replied to APP-SP that they would maintain flight level and that they were at the ideal point of descent, waiting for clearance;

• 16:19:28 - at a speed of 184 kt., the DEGRADED PERFORMANCE alert was triggered, together with a single chime. The alert was triggered concomitantly with the exchange of messages between APP-SP and the Crew;

• - APP-SP acknowledged the message and requested the aircraft to wait for clearance;

• 16:19:31 - Passaredo 2283 aircraft reported receipt of the message and thanked ATC;

• - the PIC resumed delivering the approach briefing;

• - the Second in Command (SIC) commented, "a lot of icing";

• - the AIRFRAME DE-ICING was turned on for the third time;

• - APP-SP cleared the aircraft to fly direct to SANPA position, maintaining FL170, and informed that the descent would be authorized in two minutes;

• 16:20:39 - the crew acknowledged the flight instruction received (last communication performed by the flight crew);

• - the aircraft started a right turn in order to fly to SANPA position.

• 16:20:57 — during the turn, at a speed of 169 the INCREASE SPEED alert was triggered, in conjunction with a single chime. Immediately afterwards, vibration noise was heard in the aircraft, simultaneously with the activation of the stall alert;

• 16:21:09 - control of the aircraft was lost, and it entered an abnormal flight attitude until colliding with the ground. The aircraft rolled to the left to a bank-angle of 52 degrees, and then rolled to the right to a bank- angle of 94 degrees, performing a 180-degree turn in a clockwise direction. Subsequently, the turn was reversed to an anticlockwise direction, with the aircraft completing five full rotations in a flat spin before crashing into the ground.

Click on image to see it isolated

The ICING light would blink with the detection of an Icing condition and the Anti-Icing and/or De-lcing  (AIFRAME) were not selected to ON, followed by single chime. The light would remain illuminated in a continuous fashion with the systems turned on.

 

Anti-Icing and De-Icing Systems

 

The Anti-lcing functions were energized electrically, whereas the De-icing ones were provided by means of pneumatic pressure.

 

The APM system needed to be checked by the crew on a daily basis, and in case of a failure, an amber-colored FAULT message would illuminate on the APM panel.

If the aircraft's drag increased due to ice accumulation and performance was degraded, resulting in loss of cruise speed, alerts in three levels were triggered and presented to the pilots on both alert panels Of the APM, as follows:

• 1st Level - CRUISE SPEED LOW

The blue-colored message would indicate performance degradation Of around 10%, with reduction Of the Indicated Air Speed (IAS) during the cruise phase by at least 10 kt. below the speed computed by the APM.

This alert would be triggered only during the cruise phase.

• 2nd Level - DEGRADED PERFORMANCE

The amber-colored message would be followed by a single chime and a master caution alert, indicating a significant performance degradation in the range between 22% and 28%, induced by a significant increase in aerodynamic drag, causing a drop in cruise IAS of around 15 to 20 knots below the speed computed by the APM. This alert could be triggered during climb, cruise, Or descent.

• 3rd Level - INCREASE SPEED.

The amber-colored message would appear flashing, followed by a single chime and a master caution alert, indicating that the degraded performance condition had worsened , reaching an IAS value below the ICING BUG + 10 kt. This alert could be triggered during climb, cruise, or descent.

 

The pilot has set the ICING BUG SPEED for SEVERE ICING CONDITION to 165 Knots.

In addition to the speed alerts (emitted by the APM), the airspeed indicators of the left- and right-hand cockpit stations had BUGS for reference, particularly for minimum speed maneuvers at low bank, flaps O', and icing conditions (VMLBO ICING), The said BUGS could be adjusted manually.

 

The ICING BUG needed to be adjusted by the pilots for each flight in accordance with the aircraft's weight, in order to indicate the minimum speed for a flight in icing conditions and with flaps retracted. The VMLBO ICING.

IF SOME ICE MAKE THE RUDDER TO LOSE ITS FUNCTION - VOEPASS CRASH ATR-72-500 IN BRAZIL

 ‘Not icing threw to the ground the aircraft, but the spiral descent flight in flat spin’; the VOEPASS’ aircraft ATR-72-500 performing the flight 2Z-2283 outbound Cascavel, PR airport (SBCA, ICAO code) to São Paulo Guarulhos airport (SBGU) in Brazil, on Aug 9, 2024. 

Spin recovery requirement

 Aerodynamic balance and mass balance:

aileron, elevator, and rudder tabs of ATR-72-600

SOURCE:

AIRCRAFT DESIGN

A Systems Engineering Approach

Mohammad H. Sadraey

Daniel Webster College, New Hampshire, USA

The level of acceptability relates to the ease of flight and flight safety. According to airworthiness standards, an aircraft with any level of acceptability from one to three is allowed to fly, but for the design of control surfaces, level 1 must be the objective. An aircraft with level 1 can only terminate flight phase A safely and in other phases may be run out of control. When an aircraft is in level 1, there is no failure during phases of flight. When an aircraft has one failure per 1 000 000 flights, it will be considered to be at level 1. When an aircraft has one failure per 10 000

flights, it will be considered to be at level 2. If any aircraft has one failure per 100 flights, it is considered to be at level 3. An aircraft in level 3 is recommended to be retired to avoid an accident, because any time a system or component fails, an accident may occur. The control surfaces must be designed such that the level 1 of handling qualities is achieved.

Spin Recovery

One of the most important roles of a rudder in the majority of airplanes is spin recovery.

The most significant instrument to recover aircraft from a spin is a powerful rudder. Spin is a self-sustaining (auto-rotational) spiral motion of an airplane about the vertical (z ) axis, during which the mean angle of attack of the wings is beyond the stall.

The typical range of some spin parameters is as follows:

angle of attack (α), 30–60 deg;

rate of descent (ROD), 20–100 m/s; [65 ft/s – 168 ft/s] {3900 ft/min – 10,080 ft/min}

rate of spin (Ω), 20–40 rpm;

helix angle (γ), 3–6 deg;

and helix radius (R), half of the wing span.

 The design of the rudder

The rudder is the most significant element in spin recovery to stop rotation. The primary control for spin recovery in many airplanes is a powerful rudder.

The convention for the positive rudder deflection is defined as the deflection to the

left (of the pilot). A positive rudder deflection creates a positive side force (i.e., in the positive y direction) but results in a negative yawing moment (i.e., counterclockwise).

four parameters must be determined: (i) rudder area (S R), (ii) rudder chord (CR), (iii) rudder span (bR), (iv) maximum rudder deflection (±δRmax ), and (v) location of inboard edge of the rudder (bRi).

FAR Part 25 Section 25.147 requires the following:

It must be possible, with the wings level, to yaw into the operative engine and to safely make a reasonably sudden change in heading of up to 15 deg in the direction of the critical inoperative engine. This must be shown at 1.3 VS for heading changes up to 15 deg, and with (i) the critical engine inoperative and its propeller in the minimum drag position; (ii) the power required for level flight at 1.3 VS, but not more than maximum continuous power; (iii) the most unfavorable center of gravity; (iv) landing gear retracted; (v) flaps in the approach position; and (vi) maximum landing weight.

The rudder plays different roles in different phases of flight for various aircraft. Six

major functions of a rudder are: (i) cross-wind landing, (ii) directional control for balancing asymmetric thrust on multi-engine aircraft, (iii) turn coordination, (iv) spin recovery, (v) adverse yaw, and (vi) glide slope adjustment for a glider.

Example,

Consider the maximum allowable rudder deflection is ±25 deg. Is this rudder able to satisfy the spin recovery requirement at 15 000 ft altitude? Assume the aircraft will spin at an angle of attack of 40 deg.

 We need to keep in mind that at 15,000 feet the RUDDER deflection demands an increase because of air density, but that deflection at that altitude must be less than 30 degrees. After all calculations we’ll get 29.11 degrees of the rudder deflection.

There is a mnemonic rule to pilots’ remembrance – PARE:

P – Power to idle

A – Ailerons on neutral

R – Rudder full opposite direction of rotation

E – Elevators forward to break the stall

For a flight instructor it has no relevance icing condition on the aircraft. The ICE & RAIN PROTECTION SYSTEM was developed to keep the plane from icing condition. 

The most interesting thing in any abnormal flight is to save the flight from the instant the abnormality has presented to the pilot, so the pilot must be prompted to manage the abnormal flight.

An airplane only gets into spiral flat spin descent flight if the RUDDER trim has lost its function to keep the plane flying in straight line (forward heading).  Any plane before takeoff must have its rudder trim set to zero deflection.

To take an airplane from a diving spiral flat spin flight, you must immediately and fully push on the pedal at the same side of the highest wing, and you must keep the ailerons on neutral.  

 

Real spiral flat spin training overview

The main difference between a normal spiral spin descent flight and a flat spiral spin descent flight is the “screw thread” shape of the descent flight.

On the flat spiral spin descent flight, the aircraft nose keeps aligning to the Earth horizon (minimum nose up) almost the entire descent flight, in other words, the nose does not point directly to terrain. The airplane makes each descent turn increasing the spiral thread diameter.  If the initial descent turn has 10 meters of radius, the last turns before colliding into the terrain will have about 20 meters of radius.

On the contrary, the normal spiral spin descent flight, the aircraft nose will fall pointing directly to terrain. The plane makes all descent turns very near to the vertical spiral axis. It starts the first turn with 10 meters of radius and at the final turn the airplane will make a turn with 10 meters of radius centered on spiral vertical axis.

Spin Recovery

One of the most important roles of a rudder in majority of airplanes is spin recovery. The most significant instrument to recover aircraft from a spin is a powerful rudder. Spin is a self-sustaining (auto-rotational) spiral motion of an airplane about vertical (z) axis, during which the mean angle of attack of the wings is beyond the stall. Almost since man first flew, spinning has caused many fatal accidents, so that most accidents were due to spin. During years 1965 to 1972, US Navy has lost an average of 2 aircraft per month and total of 169 aircraft due to spin, the list of which is headed by 44 fighter aircraft F-4s (Phantom). This statistics show the crucial role of the rudder in a spin.

Spin is a high angle of attack/low airspeed situation; the airspeed will be hovering somewhere down in the stall area. Spin has two particular specifications: 1. Fast rotation around vertical axis, 2. Fully stalled wing. Spin is usually starts after wing stalls. One of the reasons why aircraft enter into spin is that inboard of the wing stalls before outboard of the wing, in other word, lift distribution over the wing is not elliptic. Spin is recovered by a procedure which all control surfaces (elevator, aileron, and rudder) contribute; particularly the rudder in an apparently unnatural way. The rudder is the most significant element is spin recovery to stop rotation. The primary control for spin recovery in many airplanes is a powerful rudder.

The rudder must be powerful enough to oppose the spin rotation in the first place. A spin follows departures in roll, yaw and pitch from the condition of trim between the predominantly pro-spin moment due to the wings and the generally anti-spin moments due to other parts of the aircraft. If spin is not recovered, aircraft will eventually crash. The criterion for rudder design in a spinnable aircraft may be spin recovery. Acrobatic and fighter airplanes are usually spinnable, but there are some airplanes such as some transport aircraft that are spin-proof or un-spinnable.

Typical range of some spin parameters is as follows: angle of attack (α): 30 to 60 degrees; rate of descent (ROD): 20 to 100 m/sec; rate of spin (Ω): 20 to 40 rpm; helix angle (σ): 3 to 6 degrees; and helix radius (R): half of wing span. As angle of attack increases; rate of rotation increases; and helix radius decreases.

 Basically, the rudder is not the only factor to feature an acceptable spin recovery. Two other significant factors are as follows:

1. aircraft mass distribution and aircraft moments of inertia,

2. fuselage side area and cross section.

It is very important that the inertia term be made anti-spin (negative for right spin) for recovery. When the magnitudes of pitch (Iyy) and roll (Ixx) inertia are close, the effect of inertia term is little; and hence the rudder, will be the primary control for spin recovery. But whenever the inertia term becomes quite significant, they have a considerable impact on the spin motion, and thus, the size of rudder. The application of aileron to aid recovery in generally not recommended due to its nuisance impact. In some cases, the use of ailerons while stopping a spin may suddenly cause a spin in the reverse direction.

ONLY ONE QUESTION TO PILOTS BUT THEY ANSWERED IT WITHOUT CONSISTENCE

 

Source: FlightSafety Fundation

Final Report to Flight Safety Foundation

Go-Around Decision-Making and Execution Project Tzvetomir Blajev, Eurocontrol

(Co-Chair and FSF European Advisory Committee Chair)

Capt. William Curtis, The Presage Group

(Co-Chair and FSF International Advisory Committee Chair)

AIRBUS A321 G-OATW DAMAGE TO CABIN WINDOWS AND TO THE HORIZONTAL STABILIZER

 

Aircraft Type and Registration: Airbus A321-253NX, G-OATW

No & Type of Engines: 2 CFM International SA LEAP-1A33 turbofan

engines

Year of Manufacture: 2020 (Serial no: 10238)

Date & Time (UTC): 4 October 2023 at 1151 hrs

Location: London Stansted Airport

Type of Flight: Commercial Air Transport (Passenger)

Persons on Board: Crew - 11 Passengers - 9

Injuries: Crew - None Passengers - None

Nature of Damage: Damage to several cabin windows and impact

damage to the left horizontal stabilizer

Commander’s License: Airline Transport Pilot’s License

Commander’s Age: 54 years

Commander’s Flying Experience: 4,905 hours (of which 2,300 were on type)

Last 90 days - 128 hours

Last 28 days - 27 hours

Information Source: AAIB Field Investigation

History of the flight	História do voo
ENGLISH	PORTUGUÊS (BRASIL)
The aircraft was scheduled to embark on a multi-sector charter away from base for several weeks. On board were three pilots, an engineer, a load master and six cabin crew. The co-pilot was the PF for the first sector, which was a positioning flight from London Stansted Airport to Orlando International Airport, Florida. Prior to the boarding of the passengers the commander completed a pre-flight inspection of the exterior of the aircraft and noted nothing untoward. At the same time, several engineers were carrying out an external inspection; the daily and ETOPS1 inspections, prior to departure. In addition to the 11 crew, there were nine passengers on board. The passengers sat together in the middle of the aircraft just forward of the overwing exits.	A aeronave estava programada para embarcar um fretamento para vários destinos, longe da base por várias semanas. A bordo estavam três pilotos, um engenheiro, um despachante operacional de voo [DOV] e seis tripulantes de cabine [comissárias de bordo]. O copiloto era o PF do primeiro destino, o qual  era um voo de substituição de aeronave partindo do Aeroporto Stansted em Londres [EGSS] para o Aeroporto Internacional de Orlando [KMCO], na Flórida [EUA]. Antes do embarque dos passageiros, o comandante completou uma inspeção pré-voo no exterior da aeronave e nada adverso notou. Ao mesmo tempo, vários engenheiros realizaram uma inspeção externa; as inspeções diárias e de ETOPS1, antes da partida. Além dos 11 tripulantes, havia nove passageiros a bordo. Os passageiros sentaram-se juntos no meio da aeronave, logo à frente das saídas de asa.

The aircraft departed a few minutes ahead of schedule and took off from Runway 22. Several passengers recalled that after takeoff the aircraft cabin seemed noisier and colder than they were used to. As the aircraft climbed through FL100, and the seatbelt signs were switched off, the loadmaster, who had been seated just in front of the other passengers, walked towards the rear of the aircraft. He noticed the increased cabin noise as he approached the overwing exits and his attention was drawn to a cabin window on the left of the aircraft. He observed that the window seal was flapping in the airflow and the windowpane appeared to have slipped down. He described the cabin noise as ‘loud enough to damage your hearing’. Figure 1 shows the window in flight.

A aeronave partiu alguns minutos antes do previsto e decolou da pista 22. Vários passageiros lembraram que, após a decolagem, a cabine da aeronave parecia mais barulhenta e fria do que estavam acostumados. Quando a aeronave passou pelo nível de voo de 10.000 pés, e os sinais do cinto de segurança foram desligados, o DOV, que estava sentado na frente dos outros passageiros, caminhou em direção à parte traseira da aeronave. Ele notou o aumento do ruído na cabine quando se aproximou das saídas sobre as asas e sua atenção foi atraída para uma janela da cabine à esquerda da aeronave. Ele observou que o selo da janela estava batendo no fluxo de ar e a vidraça parecia ter escorregado para baixo. Ele descreveu o barulho da cabine como "alto o suficiente para danificar sua audição".

The loadmaster told the cabin crew and then went to the flight deck to inform the commander. At this stage, the aircraft was climbing through FL130, there were no abnormal indications on the flight deck and the aircraft pressurization system was operating normally. The flight crew stopped the climb at FL140 and reduced airspeed whilst the engineer, and then the third pilot, went to look at the window. Having inspected the window, it was agreed the aircraft should return to Stansted. The cabin crew told the passengers to remain seated and keep their seatbelts fastened and reminded them about the use of oxygen masks if that became necessary.

O DOV contou para tripulação de cabine [comissárias de bordo] e, em seguida, foi ao cockpit para informar o comandante. Nesta fase, a aeronave estava subindo e passando o nível de voo de 13.000 pés, não havia indicações anormais na cabine de comando e o sistema de pressurização da aeronave estava operando normalmente. A tripulação de voo [pilotos] parou a subida no nível de voo de 14.000 pés e reduziu a velocidade, enquanto o engenheiro e depois o terceiro piloto, foi olhar a janela. Ao ter inspecionado a janela, foi combinado que a aeronave deveria retornar a Stansted. A tripulação de cabine disse aos passageiros para permanecerem sentados e manterem os cintos de segurança afivelados e os lembrou acerca do uso de máscaras de oxigênio se isso se tornasse necessário.

Previous activity	Atividade anterior
The day before the occurrence flight the aircraft had been used for filming on the ground, during which external lights had been shone through the cabin windows to give the illusion of a sunrise. The lights were first shone on the right side of the aircraft for approximately five and a half hours, with the light focused on the cabin windows just aft of the overwing exits. The lights were then moved to the left side of the aircraft where they illuminated a similar area on the left side for approximately four hours.	No dia anterior ao voo da ocorrência, a aeronave havia sido usada para filmagens em solo, durante as quais lâmpadas externas brilharam através das janelas da cabine para dar a ilusão de um nascer do sol. As lâmpadas de iluminação [de estúdio fotográfico e filmagem] brilharam primeiro no lado direito da aeronave por aproximadamente cinco horas e meia, com a luz focada nas janelas da cabine logo atrás das saídas da asa. As lâmpadas foram então movidas para o lado esquerdo da aeronave, onde iluminaram uma área semelhante no lado esquerdo por aproximadamente quatro horas.
Photographs taken during filming showed six sets of flood lights on both sides of the aircraft.	Fotografias tiradas durante as filmagens mostraram seis conjuntos de holofotes em ambos os lados da aeronave.
The Airbus A321 is certified to operate in a maximum outside air temperature of 55°C. The specification for the cabin windows requires them to withstand a maximum temperature of 80°C, thereby providing a safety margin. The outer and inner windowpanes are made of stretched acrylic. This requires cast acrylic to be heat soaked near its softening point whilst it is stretched into its finished shape. The performance specification includes post-production dimensional stability properties and there are two requirements relating to thermal relaxation.	O Airbus A321 é certificado para operar em uma temperatura máxima do ar externo de 55°C. A especificação para as janelas da cabine exige que elas suportem uma temperatura máxima de 80°C, proporcionando assim uma margem de segurança. As vidraças externas e internas são feitas de acrílico esticado. Isso requer que o acrílico fundido seja embebido em calor perto de seu ponto de amolecimento enquanto é esticado para sua forma final. A especificação de desempenho inclui propriedades de estabilidade dimensional pós-produção e há dois requisitos relacionados ao relaxamento térmico.
The tour company commissioned a video production company to film an advert on the aircraft. The video production company contracted various other individuals required for the filming, including the director of photography and the gaffer (see below), and hired the required equipment, including the external lighting. The filming was organized by the tour company in collaboration with the operator, video production company, airport authority, fixed base operator and the contractors. A permit from the airport authority was required to conduct the filming airside at Stansted. It took place outside the hangar of the fixed base operator who provided facilities during the filming such as catering and escort to and from the aircraft.	A empresa de turismo contratou uma produtora de vídeo para filmar um anúncio [de publicidade] na aeronave. A produtora de vídeo contratou várias outras pessoas necessárias para a filmagem, incluindo o diretor de fotografia e o técnico de iluminação (veja abaixo), e contratou os equipamentos necessários, incluindo a iluminação externa. As filmagens foram organizadas pela empresa de turismo em colaboração com o operador [da aeronave], a produtora de vídeo, a autoridade aeroportuária, o operador de atendimento de pista [FBO] e os empreiteiros. Uma autorização da autoridade aeroportuária foi necessária para realizar as filmagens em Stansted. Ocorreu fora do hangar do operador de atendimento de pista [FBO] que forneceu as instalações durante as filmagens, como catering [serviço de alimentação a bordo] e acompanhamento de e para a aeronave.

External lighting	Iluminação externa
Six halogen Maxibrute 12 lights7 were used for the filming, with a combined lighting capacity of 72,000 W. The filming company reported that the lights were switched on for four hours on the left side of the aircraft and five and a half hours on the right side. The lights on the left side were focused on six windows behind the overwing emergency exit. The lights on the right side were spread over a larger area. Photographs of the filming showed that the lights were approximately 6 to 9 m from the window areas where damage occurred.	Seis conjuntos de lâmpadas halógenas Maxibrute 12 foram usadas para as filmagens, com uma capacidade de iluminação combinada de 72.000 Watts. A empresa de filmagem informou que as lâmpadas foram acesas por quatro horas no lado esquerdo da aeronave e cinco horas e meia no lado direito. As lâmpadas do lado esquerdo estavam focadas em seis janelas atrás da saída de emergência. As lâmpadas do lado direito estavam espalhadas por uma área maior. Fotografias das filmagens mostraram que as lâmpadas estavam a aproximadamente 6 a 9 m das áreas das janelas onde ocorreram danos.
Online datasheet for the lights included the information	Ficha técnica on-line para as lâmpadas incluía as informações
The minimum recommended distance from the object to be illuminated is based on the lighting manufacturer’s test data. According to this test data, when an object is illuminated by a single Maxibrute 12 light from 10 m, the surface temperature will increase by 30°C after 30 minutes. The temperature will then remain constant. If the light is 8 m from the object, the surface temperature will increase by 45°C and, if the light is 6 m away, the temperature will increase by 64°C. The combined effect of six Maxibrute 12 lights, with some of their output overlapped, is unknown. The gaffer was not aware of the manufacturer’s datasheet or any other written guidance or limitations on how the Maxibrute 12 lights should be used.	A distância mínima recomendada do objeto a ser iluminado é baseada nos dados de teste do fabricante da iluminação. De acordo com esses dados de teste, quando um objeto é iluminado por uma única lâmpada Maxibrute 12 distante 10 metros, a temperatura da superfície aumentará em 30°C após 30 minutos. A temperatura então permanecerá constante. Se a lâmpada estiver a 8 metros do objeto, a temperatura da superfície aumentará em 45°C e, se a lâmpada estiver a 6 metros de distância, a temperatura aumentará em 64°C.  O efeito combinado de seis lâmpadas Maxibrute 12, com algumas de suas saídas sobrepostas, é desconhecido. O técnico de iluminação não estava ciente da ficha técnica do fabricante ou de qualquer outra orientação por escrito ou limitações de como as lâmpadas  Maxibrute 12 deveriam ser usadas.

Personnel	Pessoal
The gaffer was an electrician who had worked in the filming industry for more than 30 years. There are no technical qualifications or requirements to become a gaffer, but most people progress to the role via the electrical trade.	O chefe técnico de iluminação era um eletricista que trabalhava na indústria cinematográfica há mais de 30 anos. Não há qualificações técnicas ou requisitos para se tornar um técnico de iluminação, mas a maioria das pessoas progride para a função através do comércio elétrico.
Heating effects of solar energy and halogen lights	Efeitos de aquecimento da energia solar e lâmpadas halógenas
Spectral power distribution and absorptivity A typical spectral power distribution for a halogen bulb shows that most of the energy is in the infrared (IR) wavelengths. Energy from the sun is filtered by the atmosphere, dust and humidity, and mostly arrives at lower altitudes in the visible spectrum.	Distribuição de potência espectral e distribuição de absorção típica de potência espectral [raios Ultravioleta A] para uma lâmpada halógena mostra que a maior parte da energia está nos comprimentos de onda infravermelho (IR). A energia [ultravioleta e infravermelho emitida] do Sol é filtrada pela atmosfera, poeira e umidade, e chega principalmente em altitudes mais baixas no espectro visível.
Previous occurrences	Ocorrências anteriores
There have been at least four previous occurrences (one Airbus A321 and three Boeing 787) where acrylic cabin windows have been damaged by high-intensity lights during filming. The damage was identified and repaired before flight, so it is likely that it was more obvious than G-OATW.	Houve pelo menos quatro ocorrências anteriores (um Airbus A321 e três Boeing 787) em que janelas de acrílico da cabine foram danificadas por lâmpadas de alta intensidade durante as filmagens. O dano foi identificado e reparado antes do voo, então é provável que tenha sido mais óbvio do que G-OATW.