MAX KINGSLEY-JONES / LONDON, DAVID LEARMOUNT / LONDON, GUY NORRIS / LOS ANGELES, PAUL PHELAN / CAIRNS, SIMON WARBURTON / PARIS & GRAHAM WARWICK / WASHINGTON DC
The airline security challenge after 11 September is twofold: stopping it happening again and restoring passenger confidence
The events of 11 September added a ghastly new dimension to aviation-related terrorism. Until that day the only use of aircraft as guided weapons had been Japanese kamikaze attacks in Second World War. That horrified the world then, but at least those were lone military pilots in military aircraft striking military targets.
Now things have changed, and regulators and the aerospace industry are working together on strategies both to counter this new threat, and to shore up security defences which have had their many weaknesses starkly revealed. The attacks have exposed a security system - particularly in the USA - which is unstructured, riddled with regulatory and operational complacency and poorly policed. Terrorism in this unexpected, no-holds barred mode shows air crews all over the world to be unprepared, with inadequate in-flight protection should the ground defences fail.
The USA has provided almost all of the early action to revise and upgrade security, because it is clearly the major terrorist target, and because it is the least well-prepared of all the nations with a large air transport industry in the provision of airport security for domestic flights. Following early suspicions that the 1996 Trans World Airlines flight 800 Boeing 747 mid-air explosion might have been the result of sabotage, the then Vice-President Al Gore was directed to set up a commission to make recommendations on air transport safety and security. When it reported in February 1997, the commission recommended that security standards applied to US domestic flights should be as rigorous as those for international ones. The US Air Transport Association opposed this so vigorously, on the grounds that it would slow the system, that the recommendation was not put into effect.
One reaction has been a call, from the public and Congress, for the federalisation of airport security services. Even the airlines have called on government to take over the responsibility for security provision and fund it with a ticket tax. But federalisation is not the answer, according to Airports Council International - North America (ACI-NA) president David Plavin: "The key issue, in our view, is to improve the hiring, training, testing and proficiency of those individuals conducting the screening of passengers and baggage," says Plavin. He refers to the need for "security professionals" rather than what has been widely described by US industry commentators as a motley band of badly paid, poorly trained people who stay in their job, on average, for less than a year. There is no certainty, however, that the terrorists who committed the 11 September atrocity would have been detected at European, airports. Since they used knives with tiny blades ("carpet cutters"), scanner operatives might have ignored them.
Rapid response
Even as the dust from the 11 September attack began to settle, US Transportation Secretary Norman Mineta set up two high-level rapid-response teams to reduce the vulnerability of the air transport industry and to help save it from the extraordinary flat-spin that it entered on 11 September.
While one team examined airport security, the second focused on aircraft. Given the job of combating the threat and restoring public confidence in commercial aviation, the aircraft team was charged with several key tasks: firstly, to suggest ways to deter hijack plans and make it too difficult, expensive or undesirable to use aviation as a weapon of terror; secondly, to prevent access to the flightdeck by unauthorised personnel; and, thirdly, to delay access to the cockpit to give the crew time to foil any attempt to take over an airborne aircraft. Lastly, a team was asked to study methods for recovering control through aggressive crew response.
A little more than two weeks later, on 1 October, the US Department of Transportation's aircraft rapid-response team came out with a 17-point set of recommendations that formed the blueprint for subsequent Federal Aviation Administration action. The main conclusions included calls for secure flight deck "barrier devices", new procedural and identification requirements for access of all personnel to flight decks, security training for all crew members and methods of delivering "government security advisories" to crews in quick time. It also included a call for methods to ensure an uninterruptable transponder response, and the identification of revised procedures in crew flight-training to counter an attempted hijacking.
Two days later the FAA added a timetable for US operators to reinforce cockpit doors "to restrict the unwanted entry of persons into the flightcrew compartment" and, at the same time, provided temporary relief from airworthiness regulations that simple quick fixes could never meet. These particularly included FAR 25 regulations covering decompression and emergency evacuations.
The FAA schedule calls for airlines to start implementing interim fixes by the first week of November and complete the temporary retrofits on their entire fleets within 90 days. The airlines must then file a plan for long-term solutions, and begin to implement them within 180 days. These retrofits must be completed in 18 months.
Providing solutions
While airline attention has been focused on the short-term fixes for flightdeck doors, it is the design of longer term secure aircraft systems that is challenging the industry at large.
The main difficulty is how to reinforce doors and bulkheads against deliberate attack, while ensuring their designs meet the stiff airworthiness requirements for depressurisation, emergency exit for the crew and emergency access for rescuers.
Other problems include concern over cabin security, the use of video monitoring, flightdeck and system changes to protect Mode S transponder and cockpit radio transmissions from interruption, and the potential security use of the broadband capabilities of the newest generation of in-flight entertainment systems.
B/E Aerospace's Flight Structures (FSI) is among those playing a leading role in developing long-term structural reinforcements. "The basic load we're looking to defeat is a fully loaded drinks cart weighing about 300lb [136kg]," says the company. "Anything can be defeated eventually, but the aim is to make the flightdeck resistant to forced entry, and make the door and bulkhead ballistic-resistant - not proof," it adds. By making the door difficult to breach, the company says it will at least give the crew time to land, divert, fly aggressive manoeuvres or depressurise the aircraft to foil the hijack attempts.
The designers assume it is useless to strengthen doors to resist larger forces from explosives. "Not many guns are going to get aboard, and if the hijacker's got a bomb then it's probably all over anyway. We are not so much worried about him having a gun, but rather the impact of bullets from the sky marshal's gun," says the company, which has tested the steel-reinforced barrier against a variety of calibres, ranging from 12-gauge high-energy rounds and easy-to-conceal 0.22in and 9mm weapons, to bigger 0.45in and hollow-point 0.357in magnum high-velocity bullets.
Key issue
By designing the door with louvres, hinged panels and pressure-activated release latch pins, FSI gained FAA certification for its solution, available from January onwards. The key issue, says the company, was preventing the reinforced door dubbed AeroGuard from becoming an internal pressure bulkhead in the event of a sudden decompression. "This would create dangerous load paths otherwise," it adds.
Raisbeck Engineering's compliant armoured cockpit security system entering service with Alaska Airlines on its Boeing 737 fleet, meets seven FARs and will be tested for "additional FAA requirements" in the next 18 months, says the Seattle-based company. Unlike many designs, the Raisbeck door incorporates two 32mm- (1.3in) thick bullet-proof glass windows to provide the flight crew with a view of the cabin. In addition, the cockpit door locking/unlocking mechanism can be remotely operated from the centre pedestal.
While several efforts are designed to respond quickly to specific issues such as door security, others are taking a more general approach. Airbus and Boeing, while engaged in specific tasks to strengthen doors and bulkheads, are also gearing up to embrace other manufacturers and disciplines. Honeywell, a leading systems house, has outlined a layered approach to improving security that extends beyond the aircraft, and is likely to be closely involved with both airframe manufacturers as long-term goals become clearer.
Short-term improvements suggested by Honeywell in the next year place enormous emphasis on boosting situational awareness, for both the flight crew and authorities on the ground.
They include a new airborne one-way video-audio system that will allow the crew to keep the cabin under surveillance, and an uninterruptable datalink to transmit flight data and cockpit audio to air traffic controllers in an emergency. The company also proposes a more capable Mode S transponder that could transmit aircraft identification, speed, differential GPS position and other data. Honeywell's own strengthened door, made from Spectra high modulus polyethylene fibres, will also be added to the package.
Longer-term aircraft technology could include an emergency override to prevent unauthorised disabling of critical aircraft systems such as the Mode S transponder, radios and flight recorders.
Proposed solutions also include encryption of transmissions from communications equipment, aircraft wiring tamper monitors, deployable flight data and crash-survivable cockpit video recorders that would be jettisoned from the aircraft on impact.
One of the most intriguing prospects outlined by Honeywell is a potential "envelope protection" option for fly-by-wire aircraft. Using the database already resident in the enhanced ground-proximity warning system, it would activate if the aircraft was deliberately aimed at terrain or structures.
Although the private industry view now appears to be that the events of 11 September were a one-off tragedy, safety development efforts continue apace. However unlikely, the prospect of a similar attack is too terrible to ignore.
Source: Flight International
