segunda-feira, 19 de setembro de 2016
From FlightSafety Fundation
Thrust reversal, also called reverse thrust, is the temporary diversion of an aircraft engine's exhaust so that the thrust produced is directed forward this acts against the forward travel of the aircraft, providing deceleration. Thrust reversers are used by many jet aircraft to help slow down just after touch-down, reducing wear on the brakes and enabling shorter landing distances. Reverse thrust is typically applied immediately after touchdown, often along with spoilers, to improve deceleration early in the landing roll when residual aerodynamic lift and high speed limit the effectiveness of the friction brakes located on the gear. When thrust is reversed, passengers will hear a sudden increase in engine noise, particularly seated just forward of the engines.
Thrust reverser provide a deceleration force that is independent of runway condition.
Thrust-reverser efficiency is higher at high airspeed.
Therefore, thrust reversers must be selected as early as possible after touchdown.
Thrust reverser should be returned to reverse idle at low airspeed to prevent engine stall or foreign object damage and stowed at taxi speed.
Nevertheless, maximum reverse thrust can be maintained to a complete stop in an emergency.
Factos Affecting Braking
The following factors have affected braking in runway excursions or runway overruns:
- Failure to arm ground spoilers, with thrust reversers deactivated (e. g., reliance on a thrust-reverser signal for ground-spoilers extension, as applicable).
- Failure to use any braking devices (i. e., reliance on the incorrect technique of maintaining a nose-high attitude after touchdown to achieve aerodynamic braking.
The nose-whell should be lowered onto the runway as soon as possible to increase weight-on-wheels and activate aircraft systems associated with the nose-landing-gear squat switches.
- Asymmetric thrust (i. e., one engine above idle in forward thrust or one engine failing to go into reverse thrust.
- Brake unit inoperative (e. g., reported as a "cold brake", i.e., a brake whose temperature is lower, by a specified amount, than the other brakes on the same landing gear.
- Spongy pedals (air in the hydraulic wheel-braking system.
- Anti-skid tachometer malfunction.
- Failure to adequately recover from loss of the normal braking system.
- Late selection of thrust reversers.
- No takeover or late takeover from autobrakes, when required.
- No switching or late switching from normal braking to alternate braking or to emergency braking in response to abnormal braking.
- Crosswind landing and incorrect braking technique.
sexta-feira, 9 de setembro de 2016
September 8, 2016
Contact: Laura Brown
In light of recent incidents and concerns raised by Samsung about its Galaxy Note 7 devices, the Federal Aviation Administration strongly advises passengers not to turn on or charge these devices on board aircraft and not to stow them in any checked baggage.
Replace Current Note7 with New One
on September 02, 2016
Samsung is committed to producing the highest quality products and we take every incident report from our valued customers very seriously. In response to recently reported cases of the new Galaxy Note7, we conducted a thorough investigation and found a battery cell issue.
To date (as of September 1) there have been 35 cases that have been reported globally and we are currently conducting a thorough inspection with our suppliers to identify possible affected batteries in the market. However, because our customers’ safety is an absolute priority at Samsung, we have stopped sales of the Galaxy Note7.
For customers who already have Galaxy Note7 devices, we will voluntarily replace their current device with a new one over the coming weeks.
We acknowledge the inconvenience this may cause in the market but this is to ensure that Samsung continues to deliver the highest quality products to our customers. We are working closely with our partners to ensure the replacement experience is as convenient and efficient as possible.
terça-feira, 6 de setembro de 2016
As the flight neared Dubai, the crew received the automatic terminal information service (ATIS) Information Zulu, which included a windshear warning for all runways.
The Aircraft was configured for landing with the flaps set to 30, and approach speed selected of 152 knots (VREF + 5) indicated airspeed (IAS) The Aircraft was vectored for an area navigation (RNAV/GNSS) approach to runway 12L. Air traffic control cleared the flight to land, with the wind reported to be from 340 degrees at 11 knots, and to vacate the runway via taxiway Mike 9.
During the approach, at 0836:00, with the autothrottle system in SPEED mode, as the Aircraft descended through a radio altitude (RA) of 1,100 feet, at 152 knots IAS, the wind direction started to change from a headwind component of 8 knots to a tailwind component. The autopilot was disengaged at approximately 920 feet RA and the approach continued with the autothrottle connected. As the Aircraft descended through 700 feet RA at 0836:22, and at 154 knots IAS, it was subjected to a tailwind component which gradually increased to a maximum of 16 knots.
At 0837:07, 159 knots IAS, 35 feet RA, the PF started to flare the Aircraft. The autothrottle mode transitioned to IDLE and both thrust levers were moving towards the idle position. At 0837:12, 160 knots IAS, and 5 feet RA, five seconds before touchdown, the wind direction again started to change to a headwind.
As recorded by the Aircraft flight data recorder, the weight-on-wheels sensors indicated that the right main landing gear touched down at 0837:17, approximately 1,100 meters from the runway 12L threshold at 162 knots IAS, followed three seconds later by the left main landing gear. The nose landing gear remained in the air.
At 0837:19, the Aircraft runway awareness advisory system (RAAS) aural message “LONG LANDING, LONG LANDING” was annunciated.
At 0837:23, the Aircraft became airborne in an attempt to go-around and was subjected to a headwind component until impact. At 0837:27, the flap lever was moved to the 20 position. Two seconds later the landing gear lever was selected to the UP position. Subsequently, the landing gear unlocked and began to retract.
At 0837:28, the air traffic control tower issued a clearance to continue straight ahead and climb to 4,000 feet. The clearance was read back correctly.
The Aircraft reached a maximum height of approximately 85 feet RA at 134 knots IAS, with the landing gear in transit to the retracted position. The Aircraft then began to sink back onto the runway. Both crewmembers recalled seeing the IAS decreasing and the Copilot called out “Check speed.” At 0837:35, three seconds before impact with the runway, both thrust levers were moved from the idle position to full forward. The autothrottle transition from IDLE to THRUST mode. Approximately one second later, a ground proximity warning system (GPWS) aural warning of “DON’T SINK, DON’T SINK” was annunciated.
One second before impact, both engines started to respond to the thrust lever movement showing an increase in related parameters.
At 0837:38, the Aircraft aft fuselage impacted the runway abeam the November 7 intersection at 125 knots, with a nose-up pitch angle of 9.5 degrees, and at a rate of descent of 900 feet per minute. This was followed by the impact of the engines on the runway. The three landing gears were still in transit to the retracted position. As the Aircraft slid along the runway, the No.2 engine-pylon assembly separated from the right hand (RH) wing. From a runway camera recording, an intense fuel fed fire was observed to start in the area of the damaged No.2 engine-pylon wing attachment area. The Aircraft continued to slide along the runway on the lower fuselage, the outboard RH wing, and the No.1 engine. An incipient fire started on the underside of the No.1 engine.
The Aircraft came to rest adjacent to the Mike 13 taxiway at a magnetic heading of approximately 240 degrees. After the Aircraft came to rest, fire was emanating from the No. 2 engine, the damaged RH engine-pylon wing attachment area and from under the Aircraft fuselage. Approximately one minute after, the Commander transmitted a “MAYDAY” call and informed air traffic control that the Aircraft was being evacuated.
quinta-feira, 18 de agosto de 2016
Rockwell Collins está planejando entregar o software final para Boeing para instalá-lo nas telas de cockpit do 737 MAX em meados de Setembro, seguida por entregas iniciais dos componentes finais de hardware no final do ano.
A entrega encerrará os quatro anos de trabalho de design, desenvolvimento e trabalho de testes já feitos, sendo os mais desafiantes pelo objetivo da Boeing de manter a máxima semelhança entre o 737NG e o 737 MAX, em parte para manter o tipo comum classificações entre os dois, e as mínimas “diferenças de treinamento" para os pilotos. A Boeing está planejando para 2017 as primeiras entregas do replanejado e de outra forma modernizado 737, para o qual ela reuniu mais de 3200 pedidos.
"Uma das coisas que tem sido um desafio para nós e para a Boeing é que estamos pegando um sistema de telas de 2015 e o aplicando em um avião que foi projetado em 1964 e que não mudou tanto assim em termos de sistema hidráulico, elétrico e de ar condicionado", diz Keith Stover, engenheiro-chefe do programa MAX da Rockwell Collins. "Nós estávamos tentando encaixar este novo sistema nele e fornecer recursos que não existem na aeronave atual."
O que resultou é indiscutivelmente o melhor dos dois mundos, com o cockpit imitando os 737NGs, enquanto permitindo que para certos recursos avançados, tais como a capacidade de tela dividida, mas com a flexibilidade e poder de processamento para introduzir mais recursos avançados no futuro, incluindo Transmissão de Vigilância Dependente Automática - ADSB "DENTRO" das aplicações de vigilância.
O cockpit do Boeing MAX apresenta quatro grandes telas nos formatos 15,1 polegadas dispostas lado a lado em todo o painel, substituindo seis telas construídas pela Honeywell de 8 X 8 polegadas exibidas em uma disposição de "T" nos modelos de Boeing NG. O hardware Rockwell Collins inclui as quatro telas, dois computadores de processamento localizados no alojamento de eletrônicos e novos painéis de interruptores no console central.
As telas são as versões de terceira geração das telas de grande formato que Rockwell Collins desenvolveu para o Boeing 787. A fabricante está usando a tela de segunda geração no cockpit do avião-tanque aéreo KC-46 Pegasus da Força Aérea. As diferenças entre a primeira e a terceira geração incluem a introdução de novos LEDs e LCDs, uma redução na profundidade do monitor para 8,9 centímetros nos monitores de 20 centímetros e uma diminuição no peso para 4,8 Kg nos de 7.1 Kg. Uma vez certificados, Stover diz, a tela de monitor dos Boeings MAX será adaptável para o Boeing 787.
quinta-feira, 4 de agosto de 2016
Halon replacement deadlines
In 2010, the European Commission adopted cutoff and end dates for essential-use exemptions for halon on airplanes operating in the European Union. The International Civil Aviation Organization adopted halon replacement deadlines in 2011, and Underwriters Laboratories will withdraw its standard for halon in handheld fire extinguishers in 2014.
Aggressively pursuing a fire means taking immediate action to determine the source of hot spots, smoke, and/or flames. The crew should quickly evaluate the situation, gain access to the fire, and attack the fire using all available resources, which may include deadheading crewmembers or able-bodied persons (ABP).
This term describes the area just below the floor, outboard of the cargo compartment areas. In narrow and widebody aircraft, this area houses wire bundles, hydraulic lines, and other electrical components. (See Appendix 2, Typical Widebody Cross-Section.) c. Circuit Breaker. Circuit breakers are designed to open an electrical circuit automatically at a predetermined overload of current. d.
Halon is a liquefied gas that extinguishes fires by chemically interrupting a fire’s combustion chain reaction, rather than physically smothering it. This characteristic is one of the main reasons that halon extinguishers are effective when the exact source of the fire cannot be positively determined. Halon fire extinguishing agents that have been approved for use in aircraft include Halon 1211, Halon 1301, and a combination of the two (Halon 1211/1301). Both are typified as “clean agents,” leaving no agent residue after discharge. Approved halon-type extinguishers are three times as effective as carbon dioxide (CO2) extinguishers with the same weight of extinguishing agent.
Insulation blanket burn-through protection
Fire-protective insulation blankets are designed to resist burn-through from a fuel fire next to the bottom half of the fuselage
Photoelectric-area type. These detectors are designed to detect the presence of smoke particles in the air by reflection of scattered light. They also rely on particles in the air being convectively carried into a sensing chamber where light from a pilot lamp is transmitted through a sensing chamber. If smoke is present, it will reflect light onto a photocell and trigger an alarm. Newer production airplanes use photoelectric detectors based on an advanced smoke sensor utilizing two discrete wavelengths to determine the presence of smoke and to distinguish between smoke and nonsmoke aerosols. These are also mounted in the ceiling or upper sidewalls of the protected space.
Photoelectric-ducted type. These detectors are similar to photoelectric-area type detectors, but they are typically mounted behind the walls of the protected space. They differ from the area detectors in that fans draw air samples from the protected space into a series of air sampling ports in the monument walls and ceiling, and then through an aluminum tube manifold to the detectors. Current production airplanes use the more advanced area detectors mentioned above, rather than ducted photoelectric detectors.
Each smoke detection system has a built-in electronic test capability switch. This allows for the system’s electrical and detector sensor integrity to be checked at any time.
Detection of smoke is affected by compartment volume and contour, air distribution, and the amount and buoyancy of the combustion particles. Boeing conducts extensive laboratory and flight testing to determine the best location for the detector sensors to enable them to most effectively detect smoke under all conditions.
One of the largest trends in the growth of in-flight fire is due to the transportation of lithium batteries. From March 1991 to October 2012, the FAA office of Security and Hazardous Materials Safety recorded 132 cases of aviation incidents involving smoke, fire, extreme heat or explosion involving batteries and battery powered devices (Federal Aviation Administration, 2012). Lithium batteries were the majority of battery types in the incidents. (Levin, 2011)
Lithium ion batteries (Li-ion) are used to power portable electronic devices such as cellular phones, portable tablets, EFBs and digital cameras; Li-ion batteries are rechargeable. Non-rechargeable lithium batteries (Li-metal) are similar to Li-ion, but use a different electrode material – metallic lithium.
All lithium batteries present a potential fire hazard. These batteries are carried on aeroplanes as cargo, within passenger baggage, and by passengers directly. Like some other batteries lithium batteries are capable of delivering sufficient energy to start an in-flight fire (Kolly). Lithium batteries present a greater risk of an in-flight fire than some other battery types because they are also unable to contain their own energy in the event of a catastrophic failure (Kolly).
Only a small fire source is needed to start a lithium battery fire. The material around lithium battery powered devices (often plastic) melts easily and ignites adjacent cells or batteries, contributing to higher fire intensity (Webster, 2004). When shipped as cargo, batteries are packed on pallets.
Aviation accidents and incidents, believed to be caused by Li-ion battery initiated fire, have occurred when battery shipments were placed next to other cargo on the aeroplane. On 3 September 2010, UPS Flight 006, a cargo flight from Dubai, United Arab Emirates, to Cologne, Germany, crashed off airport near Dubai resulting in the deaths of the two crewmembers. The Boeing 747-400F departed Dubai but returned due to smoke in the cockpit and the indication of major fire on the main deck.
The investigation revealed that a large quantity of lithium batteries were on the flight.
Following the accident the FAA issued a SAFO stating that Halon was inefficient in fighting fires involving a large quantity of lithium batteries. A restriction was also put in place to restrict the carriage of lithium batteries carried in bulk as cargo on passenger flights. (Federal Aviation Administration, 2010)
Additionally, IATA modified the Dangerous Goods Regulations to improve risk reduction for the shipment of lithium batteries. (International Air Transport Association IATA, 2012).
Batteries travelling in passenger baggage can also start an in-flight fire. The FAA recommends that lithium batteries should not be packed in checked luggage, but kept in hand luggage and stowed in overhead aeroplane’s compartments during flight. On 17 April 2012, an in-flight battery fire incident occurred on Pinnacle Flight 4290 from Toronto, Canada to Minneapolis/Saint Paul, Minnesota (LitBat Fire TransCanada October 2011). While at 28,000ft, a passenger’s personal electronic device (an air purifier) caught fire.
During the in-flight service, the flight attendant noted that the device was on fire on the floor; its battery was burning several feet from the device. Using water from the service cart, the flight attendant put out the fire using wet paper towels. She then submerged the battery in a cup of water because the battery was still smouldering.
On the flight deck, the Captain sensed very strong burning electrical odour coming from the cabin. An emergency was declared and the flight diverted and landed safety at Traverse City, Michigan (Avherald). Li-Ion batteries such as the one described in the incident above do not need to be operating in an active circuit to catch fire and do not require a short to overheat. Incidents like this one are becoming more common as the number of personal electronic devices increase as shown in the FAA office of Security and Hazardous Materials Safety data. It is not uncommon for a passenger to carry several devices with lithium batteries.
Devices include, but are not limited to, laptop computers, tablet computers, mobile phones, electronic watches, flashlights, EFBs, and e-readers.
On a typical flight, a single aisle jet carrying 100 passengers could have over 500 lithium batteries on board. These devices are not tested or certified nor are they necessarily maintained to manufacture’s recommendations. Replacement batteries from questionable sources (‘grey’ market) can be contained within devices.
‘Grey’ market batteries may not be manufactured in accordance with international standards. It is possible that they have a greater probability than original equipment to overheat and cause a fire. Aircraft crew have no means to determine the presence of ‘grey’ market batteries or the physical condition of batteries on board.
The FAA Fire Safety Branch through cooperation with the International Aircraft Systems Fire Protection Working Group conducted several tests using standard Lithium-Ion batteries.
The tests used a standard air exchange rate of one cabin air exchange every 60 seconds using one air conditioning pack (system) with the gasper fans operating; the flight deck door was closed for all tests. The results for the first test showed that there was no visible smoke or audible warning prior to the battery event. After the battery went into thermal runaway the smoke percentage was greater than 10% light obscuration per foot for a period of approximately 90 seconds (Summer, 2012). The second test performed outlined similar results. In conclusion, the outcome of the tests prove that even in a high ventilation rate a typical COTS Li-Ion battery could pose a “significant hazard within the flight deck environment and could potentially present a catastrophic risk” (Summer, 2012).
Lavatory fire protection
Lavatory fire protection
Lavatories include systems to both detect and extinguish fires
One type of electronic device that is rapidly gaining use in all forms of aviation is the EFB. These devices are used by pilots to replace paper materials found inside the flight deck. EFBs can be divided into groups by Classes:
· Class I: Portable electronic devices (PEDs), Commercial off the shelfequipment (COTS), used as loose equipment and stowed during portions of flight.
· Class II: PED can be COTS equipment, mounted and connected via aeroplane power supply for use in flight and for charging.
· Class III: Not PEDs or COTS. Class 3 is considered installed aeroplane equipment. These are built and tested specifically for aeroplane EFB use (Summer, 2012) Class I and II are not subject to FAA airworthiness standards. However, Class II mounting and charging connections are. Class III is subject to airworthiness standards for all aspects of their operation. Because Class I and II are not subject to FAA airworthiness standards, they bring potential hazards when used as EFBs. All classes of EFBs utilize lithium-ion batteries as their primary power source.
As the number of Class I and II devices increase in their use inside the flight deck, the number of potential hazards also increases.
The FAA Technical Center conducted research on all classes of EFBs. They cited the primary concern as thermal runway of lithium batteries.
“The primary concern is the resulting fire/smoke hazards should one of the lithium-ion (Li-ion) batteries installed in these units fail and experience thermal runaway, a failure causing rapid increases in temperature, significant smoke production and at times, explosion and/or rocketing of the battery cell.”
Furthermore, the FAA tests found that:
The testing showed that even with a very high ventilation rate of one air exchange per minute within the cockpit, a typical COTS Li-ion battery could pose a significant smoke hazard within the flight deck environment. . The initial battery event occurred, at times, without warning (i.e. no visible smoke or audible event prior to failure). The battery cells failed in a very vigorous manner, at one point with enough pressure to forcefully push open the unlatched cockpit door. The most striking safety hazard however, was the volume and density of smoke that emanated from the failed battery cells.
During one test in which only four of the nine battery cells went into thermal runaway, the installed smoke meter recorded greater than 10% light obscuration/ft for a period of greater than 5 minutes and a peak value of greater than 50% light obscuration/ft, resulting in severe lack of visibility within the flight deck. (Federal Aviation Administration, 2012)
As portable electronic devices become more powerful, so will their batteries. The increasing energy densities of the batteries will also increase the likelihood of producing an uncontrollable in-flight fire. The proliferation of portable electronic devices will also increase the risk of battery failure incidents (Keegan, 2001).
Technologies are available to lessen the spread of lithium battery-fuelled fires. The FAA has requested that ISO develop a standard for Fire Containment Covers. They have also conducted testing of intumescent paint, which acts as a thermal barrier, when used in the packaging of lithium batteries. (Pennetta, 2012).
Ceiling-mounted smoke detectors
Typical faceplate of a ceiling-mounted ionization smoke detector (left) and a photoelectric smoke detector (right)
sábado, 11 de junho de 2016
Yaw Maneuver Criteria
• “Sudden Pedal Input till pedal stop” (one way) must be structurally possible from VMCA to VD
• “Sudden pedal release from full pedal input” once in steady side slip state, must be structurally possible from VMCA to VD.
Yaw Maneuver Criteria
• In case of an engine failure, the pedal deflection required for the corrective action from the pilot after 2 sec recognition time must be possible.
Loads and Rudder Travel Limitation Unit
• In other words, the structure and the load limits are dimensioned so as to match the yaw maneuver criteria with adequate rudder deflection limited by a judicious RTLU.
• However, the RTLU is not designed to protect the Rudder Structure for any “unrealistic” action of the pilot on the rudder pedals.
• Finally, the Certification Criteria do not address “all” possible asymmetry cases for load considerations (typically 2 same side engine out configuration on a quad, sharp roll maneuvers with rudder deflected …)
Typical Cases including high loads
• Engine failure case:
If, once the pilot has centered the ß target, he then commands a sharp turn unto the live engine, the side slip increases rapidly.
Thus the Yaw Damper abruptly reacts, which induces high loads.
Typical Cases including high loads
• Engine failure case
– Be aware that there is no restriction to roll the aircraft with an engine failure (no additional rudder input required)
– Furthermore with an engine failed, the maximum roll rate is limited to 7.5 o / sec (on FBW A/C at low speed, typically 160 knots).
– At VMCA and V2 min, the certification requires to demonstrate adequate roll capability, with full roll input; the maximum ß reached is around 10 o and loads are Ok.
Reason for a PTLU on A330/A340
• The “Yaw Damper” has a great authority in terms of rudder deflection and rudder deflection rate, on A330/A340 as compared to A310/A320.
• Thus, in case of a steady state side slip maneuver, the Yaw Damper decreases the initial rudder deflection so as to minimize the Side Slip.
• The PTLU is the Pedal Travel Limit Unit which limits the pedal deflection as a function of the A/C CAS.
When the pilot releases the rudder pedals suddenly to neutral, as requested by certification criteria, a peak of high loads can be reached (since the rudder pedal release is equivalent to a mechanical rudder movement of same amplitude) leading to a rudder deflection on opposite side.
Why no PTLU on A340-500/600
• The rudder channel is fully electric on the A3456
• Thus the rudder pedal directly commands the amount of rudder as a function of the IAS and pedal deflection
• At a given IAS, the rudder pedals are able to command a maximum rudder deflection, as per TLU. Any additional pedal input has no effect on the rudder (PTLU and RTLU built in the lateral law).