[see Spanish version]
Spanair Flight 5022, a Boeing MD-82 airliner, carrying 172 passengers and crew members, crashed immediately after take-off from Madrid's Barajas Airport on August 20, 2008. The crash resulted in the deaths of 153 of those on board.
Investigation Focuses on Flaps/Slats
While the cause of this crash is still under investigation it is important to keep in mind that rarely does one failure alone explain a commercial airplane crash. Aviation accidents are usually caused by a chain of events. Aviation safety is promoted by, and even dependent on, the need to break that chain of events by establishing redundancy in safety.
In the investigation of the crash of Spanair Flight 5022, the primary area of focus at this time appears to be the improper deployment of flaps and/or slats.
What are Flaps and Slats?
Flaps are part of the wing surfaces located along the rear portion of the wings that extend back and down to provide critical lift for the airplane so that it can takeoff.
The slats are also wing surfaces, but along the front edge of the wings. The flaps and slats provide the left necessary for takeoff.
What Happens if Flaps and Slats Are Not Deployed?
Failure to properly deploy flaps and slats results in insufficient lift to achieve a safe take-off. Instead of continuing to safely fly away from the ground when flaps/slats are properly deployed, a plane with improperly deployed flaps or slats would initially climb after takeoff but then stall and likely crash, precisely like Spanair Flight 5022 did.
Flight crews depend upon checklists, safety systems and warnings to help them do their jobs. Checklists are used by flight crews during taxi for takeoff to make sure that the plane is properly configured for takeoff. The pre-takeoff checklist includes a requirement to confirm that flaps and slats are properly deployed for takeoff based on indicators in the cockpit. It appears that in performing the pre-takeoff checklist the flight crew stated "Flaps OK, Slats OK" with regards to the flaps/slats settings. While this may not have been consistent with standard checklist procedures it is not clear what information the flaps and slats system indicators were providing the flight crew.
Flaps/Slats Warning Systems
Because the flaps and slats are so critical for a safe takeoff, there are safety systems designed to warn if the flaps/slats are not properly deployed for takeoff.
The Spanair Boeing MD-82 was equipped with just such a system.
The warning system on the Boeing MD-82 is called the Central Aural Warning System (CAWS). It provides a loud audible warning if there is an improper configuration of the flaps and/or slats at takeoff and the engine throttles are increased to a level consistent with takeoff power. If the warning system works properly, the flight crew would hear the aural warning and be expected to abort the takeoff and determine why the flaps/slats were not properly deployed.
Based on preliminary information, however, it appears that the CAWS system did not activate to warn the flight crew that the flaps and/or slats were not properly configured. Why the CAWS system did not operate properly will be a major focus of the investigation.
CAWS System Failure
The failure of the CAWS to function properly, and provide the flight crew with an audible warning, could be due to various reasons, including mechanical or electrical failure, design deficiencies, or improper maintenance procedures.
One possibility is that the CAWS warning was not activated because the CAWS system "believed" that the plane was airborne - not on the ground. The way the CAWS system "knows" that the plane is on the ground and potentially in a takeoff situation - rather than airborne where having flaps and slats up is generally the norm - is by a switch, usually located on the landing gear, which senses the weight of the aircraft on the wheels (called "weight on wheels switch"). When the aircraft is on the ground, the switch is compressed by the weight of the aircraft and the CAWS system "believes" it is on the ground. If, however, the switch fails the CAWS system would "think" that the plane is airborne and would not sound an alarm that the flaps and slats are not set for takeoff. If the "weight on wheels" switch did not operate properly here, that could be the result of a manufacturing defect, a system design issue, or a maintenance procedure.
Another potential explanation for why the CAWS did not sound an alarm may be because it was disabled by the flight crew. Why would the crew do this? It is a common practice in aviation, in order to conserve fuel, for pilots to taxi an aircraft before takeoff using only one engine. The amount of thrust required to taxi on the one engine, however, is much greater than if both engines were used for taxiing. The CAWS system, which would sense a significant amount of throttle movement on the one engine while taxiing would "think" that a takeoff was being attempted with the plane's flaps and slats up (since the flaps and slats are normally in the "up" position during most taxi operations) and would start to warn the flight crew of the unsafe configuration for takeoff.
Under these conditions, the CAWS system could be continuously going off while the plane is being taxied, and could be considered a "nuisance" by the flight crew. To avoid the constant soundings of the false warnings during taxi, the flight crew might have elected to pull a circuit breaker that provides power to the CAWS system. If, when the crew later readied the plane for takeoff, the crew forgot to push the circuit breaker back in and also failed to properly configure the plane for takeoff, the CAWS system would not be available to warn the flight crew about the improper takeoff configuration and a disaster could result.
The risk of forgetting to configure the flaps and slats properly could be heightened if the flight crew's normal routine is interrupted. This is quite possibly what happened with Spanair Flight 5022 when the aircraft had to return to the gate due to another system malfunction that was present during the initial taxi for takeoff.
Boeing/McDonnell Douglas Knowledge
Long before this fatal Spanair crash, Boeing-McDonnell Douglas was aware of deficiencies in its CAWS system design and the risk posed by single engine taxi operations which could result in a flaps/slats up takeoff without giving the flight crew the Long before this fatal Spanair crash, Boeing-McDonnell Douglas was aware of deficiencies in its CAWS system design and the risk posed by single engine taxi operations which could result in a flaps/slats up takeoff without giving the flight crew the proper warning. Given its knowledge and the extreme hazard of takeoff with the system disabled, Boeing-McDonnell Douglas should have utilized an alternative CAWS system design that would not repeatedly issue false audible warnings during single engine taxi operations. Other manufacturers have incorporated such an alternative design to prevent precisely this kind of failure.
Given the serious risk of harm in the event of takeoff with the CAWS disabled, the aircraft should have been equipped with a warning to the flight crew that the critical CAWS system was inoperative for whatever reason - whether due to intentionally pulling the circuit breaker or to some mechanical or electrical problem with the system, such as the "weight on wheels" switch. If the system were designed with sufficient safety redundancies, it should not have been capable of failing in the circumstances of the Spanair flight. We will need to see what the investigation reveals in this regard to determine precisely what went wrong.
This accident appears very similar to the crash of Northwest Flight 255, which occurred on August 16, 1987, while taking off from Romulus, Michigan in the United States. The flight crew of the Northwest MD-82 failed to set the flaps and slats to take-off position. An electrical problem caused the CAWS warning system to be inoperative, allowing the dangerous aircraft configuration to go unnoticed. When the aircraft took off, its wings rocked as it tried to climb. Soon after leaving the ground the plane crashed, just as the Spanair plane did, and killed 154 persons. Kreindler & Kreindler represented many families in wrongful death lawsuits that were brought as a result of this crash.
Spanair, like every airline, has the responsibility to provide a well trained and competent flight crew and a well maintained aircraft to ensure the safety of its passengers. It is very likely that Spanair will, through either its flight crew's conduct, training or maintenance of the aircraft, be at least partially responsible for the crash.
Spanair, which is 94% owned by SAS Group, flies directly to Philadelphia and to other U.S. destinations through a code share agreement with other Star Alliance carriers. These may be important factors in determining whether Spanair can be successfully sued in the United States.
As in most commercial disasters there will likely not be one sole cause of this accident - but several contributing causes. The challenge is to identify all the contributing causes. Our investigation will determine those causes and, more importantly, how they translate into legal claims.
The flying public deserves the utmost care and consideration by everyone responsible for the safe operation of the flight. When a reasonable level of safety is not achieved and a passenger suffers injury or death, any one or combination of those liable must bear the legal responsibility to compensate those injured by their careless or reckless actions.
In the Spanair Flight 5022 accident, while some liability may be attributed to Spanair related to the conduct of the flight crew, Boeing will also likely be liable for possible defects in the design or manufacturing of the aircraft, specifically the CAWS system as well as failing to properly warn the flight crew or maintainers of the danger its design poses.
There are many complex legal issues raised when a U.S. manufactured aircraft crashes abroad under the operation of a non-U.S. carrier.
U.S. courts, which generally place a significantly higher value on the loss of life than other countries' courts, may be a desirable venue in which to bring a lawsuit when a U.S. product manufacturer is implicated.
Whether such a lawsuit can be maintained and succeed in the U.S. is a very complicated legal matter which requires specific expertise. Kreindler & Kreindler LLP is the leading aviation law firm in the world, having represented more families of victims of commercial air disasters than any other law firm - including more foreign families in U.S. litigation than any other firm. We have been lead attorneys in the following major air disasters.
Pan Am 103, Lockerbie, Scotland, 1988
Avianca 52, Long Island, New York, En route from Colombia, 1990
American Airlines 965, Cali, Columbia, 1995
TWA 800, Long Island, New York, En route to Paris, 1996
SwissAir 111, Halifax, Canada, En route to Geneva, 1998
American Airlines 587, Long Island, New York, En route to Santo Domingo, Dominican Republic, 2001
September 11, 2001, World Trade Center/Pentagon/Shanksville Terror Attack, 2001
We have also had particular success in maintaining foreign crash lawsuits in the U.S. including the following instances:
Singapore Airlines 006, Taipei, Taiwan, 2000
Egypt Air 990, Atlantic Ocean, En route to Cairo, Egypt, 1999
Silk Air 185, En route from Jakarta to Singapore, 1997
Furthermore, because of our established and respected relationship with the insurers for airlines and manufacturers, most of whom are in London, we are uniquely able to represent families world wide and obtain fair settlements - often times well in excess of settlements that could be expected in the foreign jurisdictions. This is no doubt because London insurers know of our ability to prosecute foreign crash cases in the U.S. and may be more willing to resolve claims with our firm than non-U.S. and less accomplished U.S. law firms.