LFV commissioned Naverus to prepare the PBN report, called the National Aerospace Assessment (NAA), as an integrated part of its Green Flights project, which is intended to reduce the environmental load from air traffic system wide. The  NAA examined current air traffic operations in Swedish airspace and identified the PBN benefits that could be achieved in the near and mid-term. The plan also is intended to be used by LFV and other aviation stakeholders in Sweden to manage the transition to PBN, which combines satellite navigation with advanced FMCs (flight management computers) and displays) to create more flexible, efficient flight paths – in some cases where none could exist with older, ground-based navigation.

Sweden’s ANSP sees PBN procedures as a neccesary foundation for realizing the goals of the European SESAR program as well as a requirement of the International Civil Aviation Organization (ICAO), which has called on all its member states to develop a PBN roadmap by the end of 2009.  Major aviation stakeholders from around the world signed a declaration calling for states to accelerate the deployment of PBN as well, earlier this year. 

Concern about environmental issues such as aircraft noise, carbon emissions, and fuel burn will drive the transformation of Swedish airspace from existing ground based-navigation systems to a modern PBN system, the report concludes. 
 
PBN proponents believe this transformation will save money while reducing aviation’s negative environmental effects. In Sweden, they see the implementation of optimized PBN at the country’s major airports saving about nine million kg of jet fuel per year along with a more an 30,000 metric tons reduction in CO2 emissions. The initial PBN-driven fuel and emissions savings referenced in the report would grow larger over time as older aircraft are either retired or upgraded to fly the new PBN routes. 

Sweden isn’t alone in taking concrete steps toward PBN.  Last month (July), Airservices Australia also signed a contract with Naverus to design and implement an optimized nationwide PBN system.

Airbus believes the system’s main benefit is that it allows the pilot to fly the aircraft without switching out of one mode and into another during a traffic avoidance situation, thus simplifying the pilot’s required actions, and minimizing potential overreactions or inverse reactions.

Operation Overview

The new AP/FD TCAS mode essentially completes existing TCAS functionality by implementing a TCAS vertical guidance feature into the auto-flight computer that enables it to control the aircraft’s vertical speed, specifically adapted to each TCAS RA (resolution advisory). 

When a RA  is received, the pilot no longer needs to disengage the autopilot or flight director before conducting TCAS maneuvers, but instead can allow the autopilot to automatically position the aircraft to remain clear of any potential traffic conflict.

If the pilot is flying the aircraft manually when a RA is received, the flight director bars remain active and will guide pilot throughout  the TCAS maneuver.  The crew always retains the ability to override the proposed maneuver, and respond a RA by manually controlling the vertical speed by referring to TCAS indications on the pilot’s vertical speed scale.

The new agreement implements Jeppesen services that include airport moving map and charting data for the airline.  Jeppesen previously provided its charting services, including e-Link, flight planning and NavData products to Turkish Airlines, as well as its Carmen Crew Rostering and Carmen Crew Pairing products .

Airbus outlined its envisaged system recently to a delegation from the International Federation of Air Line Pilots’ Associations.

Many pilots might be skeptical both about such automation; how it would work under all situations such as heavy traffic and high terrain; and even its necessity.

Should the aircraft’s monitoring system detect an unsafe cabin pressure, it would warn the crew via the primary flight display and begin a countdown of unspecified length. If the crew doesn’t  cancel the warning or take positive control of the aircraft, the system would cause the A350 to  would perform a side-step maneuver, taking it 2.75 natical miles to the right of the designated airway to avoid conflicts with other aircraft on an airway, while automatically accounting for any existing lateral offset selected by the crew.

The aircraft would also be put into a rapid descent at maximum operating speed towards flight level 100 (10,000 feet), but adjust for minimum altitude and terrain-clearance requirements.

Airbus insists that it hasn’t committed to offering the system. “It is a potential system which could be installed but, for the moment, it is under consideration.”

I’ve listed eleven of decompression-related accidents below which show that while such episodes have occurred, they are frequently accompanied by other damage, including control systems, which could complicate the functioning of an automatic system:

• On July 27, 2008, a Qantas B-747-400 flying from Hong Kong to Melbourne, suffered a rapid decompression caused by a fuselage rupture.  The pilots executed an emergency descent to 10,000 feet and eventually landed at Manila. There were no fatalities or injuries.
• On August 14, 2005, near Marathon, Greece, a Helios Airways B-737-300 depressurized causing the pilots to become incapacitated from hypoxia, eventually leading to fuel exhaustion and a crash with 121 fatalities.
• On May 25, 2002, a China Airlines B-747 en route from Taipei to Hong Kong, broke apart in midair because of metal fatigue, which caused an explosive decompression. The aircraft crashed, killing all aboard.
• On June 10, 1990, a British Airways BAC 111, en route from Birmingham, England, to Málaga, Spain, had a windscreen panel blow out, causing the captain to be sucked halfway out of the aircraft before he was saved by a male flight attendant, who happened to be on the flightdeck at the time, and was able to grab the captain’s belt to prevent his complete ejection. The first officer landed the aircraft at  in Southampton.
• On February 24, 1989, a cargo door separated from a United Airlines B-747-100 flying from Honolulu to Auckland, which caused an explosive decompression. Nine passengers were ejected through a breach in the cabin.
• On April 28, 1988, an Aloha Airlines B-737-200 en route to Hilo, Hawaii, from Honolulu, suffered a structual failure of its fuselage, and had an explosive decompression.  A flight attendant was blown out of the airplane.
• On March 31, 1986, a Mexicana Airlines B-727-200, flying from Mazatlán to Los Angeles, had an explosive decompression caused by an overheated tire exploding, which damaged the aircraft’s hydraulic and electrical systems and created a fire. The aircraft crashed killing all 167 passengers and crew.
• On August 12, 1985, a Japan Airlines B-747-SR, on a flight from Tokyo to Osaka, suffered mechanical failures 12 minutes into flight that included an explosive decompression. The airplane became uncontrollable because of a loss of hydraulics and crashed into Mount Takamagahara 32 minutes later. All 15 crew members and 505 out of 509 passengers died.
• On August 22, 1981, a Far East Air Transport B-737-200, en route from Taipei to Kaohsiung, broke apart and depressurized from a corrosion-caused hull rupture. Twenty people were killed. 
• On June 12, 1972, a cargo door failed on an American Airlines DC-10-10, which caused a rapid decompression and a partial collapse of the passenger compartment floor, which in turn ruptured hydraulic lines, causing severe flight control problems. The pilots were able to make a safe landing at Detroit.
• On January 10, 1954, a BOAC de Havilland Comet en route from Rome to London, suffered an explosive decompression and crashed into the Mediterranean Sea, killing everyone on board.

There are three important things to note in these examples:

1. Except for the Helios Airways accident, none of these decompressions occurred independently from other serious malfunctions.  
2. Other irregularities, such as a sudden hull rupture, must have caused substantial confusion, initially.
3. In those cases where perplexity was overcome, and a successful landing was accomplished, it was largely due to the crew’s ability to analyze and improvise in ways that’s impossible to completely foresee.  

Value in terms of benefits outweighing costs must, of course, also be considered, even though it can be delicate to speak about candidly.  

Notwithstanding these complications, I applaud the initiative Airbus is taking in this initiative.  Should it come to pass, it would be another illustration of how human inspired and created technology can improve safety.

The second-phase search, undertaken with the assistance of IFREMER, a research submarine, and SHOM, a surface ship also equipped for research, explored a 75 kilometer radius around the last position message transmitted by the airplane.  The vessels also performed bathymetry (the study of the depth of ocean floor in three dimensions) over a wider perimeter, both without success.

The BEA said it would gather a team of international investigators in the next few weeks to analyze the data collected so far, including those transmitted via an automatic satelitte communications link as the tradegy took place, and will discuss the possibility of third search phase.

The Boeing CDR, which took place at Copa Airlines’ training center in Panama City, assesses the operational usability of the procedures as well as their compatibility with standard airline crew procedures. Copa is taking a lead in implementing as well as testing RNP procedures in Latin America, a form of PBN (performance based navigation, which allow more flexible and precise flight paths than have been possible before.

Jeppesen has a contract with Autoridad Aeronautica Civil (AAC), Panama’s Civil Aviation Authority, to incorporate the CAA’s requirements into the RNP procedures that Jeppesen will use in creating its final navigation charts and corresponding navigational database.

Boeing signed an agreement with the AAC this past May to provide Panama with “public” RNP procedures that are capable of serving a wide variety of equipment operated by airlines that have been approved to conduct RNP operations.  Public RNP is capable of serving a wide variety of equipment operated by users who have received approval to conduct RNP operations, but currently they are available only for approach procedures, and don’t contemplate engine-out and certain other considerations.

The Board wants a modification to Federal Regulations Part 25 to ensure that the TOWS can’t be disabled by a single failure, or if the system fails or has power removed while the airplane is operating on the ground, the flight crew is provided with a discrete and clear annunciation of its status. 

The Board also wants the FAA to:

• Examine past takeoff configuration errors, identify design elements that could mitigate them, and require inclusion of such design elements in aircraft certifications.
• Convene a meeting of experts to develop guidance on such things as checklist design, cockpit procedures and training that relate to takeoff and landing configuration.
• Require operators to modify their takeoff and landing checklists to reflect the best practices identified as a result of the meeting.

The NTSB’s action comes as Spain’s Civil Aviation Accident Investigation Commission (CIAIAC), released another report on August 17 on the Spanair MD-82 accident in August 2008 that killed 154 people. That report confirmed that the pilots didn’t know the aircraft’s flaps and slats were not extended when they attempted to take off from Madrid.

The crash occurred during the flight’s second takeoff attempt, after returning to the ramp to deal with a ram-air temperature probe problem.

Before reaching the flaps/slats item on the after-start checklist, the captain instructed the copilot to request taxi clearance.  Apparently, because of this interruption, CIAIAC says the flap/slat check was omitted.  About 10 minutes later, when the copilot was reading the ‘take-off imminent’ checklist, the cockpit-voice recording indicates that the copilot called out “eight” for the center-of-gravity position and “eleven” for the take-off flap setting of 11 degrees. While the pilot is supposed to read these figures directly from cockpit indicators and the flap/slat controls, investigators believe these cross-checks were not performed.

Flight-data recorder information showed the Spanair MD-82’s flaps were not deployed, and its cockpit damage was consistent with the flap lever being in the retracted position, which supports CIAIAC’s primary theory that the aircraft crashed because of insufficient lift without the deployment of its flaps and slats.

Investigators are still looking into the reasons why the take-off configuration alarm did not sound, but have yet to reach a detailed conclusion.

In a similar accident, on August 16, 1987, Northwest Airlines 255, a MD-82, crashed on takeoff from Detroit’s Metropolitan Airport, killing 156 people, including two on the ground. The NTSB determined the probable cause of that accident was the flight crew’s failure to use the taxi checklist to ensure the flaps and slats were extended; contributing was the absence of electrical power to the airplane takeoff warning system which thus did not warn the flightcrew that the airplane was not configured properly for takeoff. “The reason for the absence of electrical power could not be determined,” the NTSB said in its final report.

The NTSB is upset because NATCA publicly commented – in a negative fashion – on the Board’s August 13th interim report regarding the accident. 

NTSB Chairman Deborah A.P. Hersman said of NATCA’s comments: “Although we appreciate the technical expertise our parties provide during the course of an investigation, it is counterproductive when an organization breaches the party agreement and publicly interprets or comments on factual information generated by that investigation.  Our rules are set up precisely to avoid the prospect of each party offering their slant on the information.  I regret that we have had to remove NATCA from the investigation.”

Under the Safety Board’s procedures, organizations and agencies are invited to participate in NTSB investigations if they can provide technical expertise.  At the outset of an investigation, these parties sign an agreement to abide by NTSB party rules, among which is that they will not reveal investigative information being learned through that process, nor publicly comment on it. 

According to the Board, NATCA convened it own press conference on August 14th, to discuss information released earlier that day by the NTSB.  The Board reminded NATCA of its “responsibilities as a party to the investigation,” but NATCA issued a another press release discussing the Board’s investigation update, and conducted another press conference concerning the subject on August 17th.

The issue behind the disagreement is the possible role played by air traffic control might have played in this accident, and specifically whether the aircraft involved were properly informed of their impending airborne conflict by controllers in Teterboro Airport’s tower.

The airline has already designed and demonstrated RNP approaches at Fort Worth Alliance Airport, where it has a major maintenance facility, and it is now the carrier is authorized to create and publish RNP approaches elsewhere.

While other airlines are using third parties, such as Naverus or Jeppesen, Brian Will, who heads up American’s Boeing 737 and 777 programs, said his airline wanted to develop RNP procedures on its own.

 American plans certify an RNP approach at its Tulsa maintenance base next, and then will consider other airports it flies to where RNP can produce the greatest results, such as those in mountainous areas, and especially those with no instrument landing systems, will be the first considered.

Transportation Secretary Ray LaHood said the DOT’s general counsel is investigating whether any laws were violated during the incident, which began on Friday (August 7), when Continental Express Flight 2816 left Houston at 9:23 p.m. for a scheduled flight to Minneapolis. 

But after touching down at Rochester, Flight 2816’s passengers weren’t allowed out of the nearly full Embraer ERJ-145 until 6 a.m. Saturday – six hours after landing – to get some fresh air and stretch their legs. Two and a half hours after that, the passengers were finally flown to Minneapolis on the same airplane. According to reports, the airplane was initially “scheduled” to leave Rochester at 2 a.m. Saturday morning for MSP but the poor weather continued and the flight was forced to remain. Then, when the flight was told it could leave at 5 a.m., the original crew had timed out and a new crew had to be brought in, so it was delayed some more, not leaving until 8:28 a.m. and arriving at MSP at 9:15 a.m.

The passengers were finally allowed to disembark at some point after sunrise and were re-boarded before the Saturday morning departure.

The incident created uproar in the media, and could be a boost to legislation pending in the Senate that includes a provision requiring airlines to return passengers to the gate after a three-hour tarmac delay. Sens. Barbara Boxer, D-Calif., and Olympia Snowe, R-Maine, the chief sponsors of the provision, sent colleagues a letter Tuesday citing Flight 2816.

The three-hour limit is opposed by the Air Transport Association, which represents most major air carriers. The association has said a hard and fast timeframe for returning to the gate could have unintended consequences for customers, including the likelihood of more cancellations and inconvenience. 

Amy Cohn, an associate professor of industrial and operations engineering at the University of Michigan, and Peter Belobaba, who manages MIT’s Global Airline Industry Program, both of whom have done extensive research on the airline industry, attempt to make the case that the Passenger Bill of Rights legislation is wrong in an opinion piece in Forbes.com . (“Still Stuck On the Tarmac,” August 13, 2009.) 

Their answer: “Because it won’t work.”

Cohn and Belobaba concede that it’s hard to argue against the intent of the bill, which requires, among other things, that a flight which suffers a delay on an airport of more than three hours must return to a gate.  Why would anyone not be in favor of a law that gives passengers a way out, of a mess like what happened at Rochester, notwithstanding the fact that the Continental Express was caught up in a different kind of a nightmare – a diversion to an airport it doesn’t normally serve, and that wasn’t expecting it?

“Let’s consider what would actually happen if the bill were to be passed,” say Cohn and Belobaba, “How much better off would passengers stuck on the tarmac be?  Well, it depends.”

In various scenarios, Cohn and Belobaba demonstrate how difficult it is to do much that really makes things better for most passengers, no matter how much one wants to. There reasons are plain when one thinks them through, mainly because there are few good choices, relatively speaking, and many are even contradictory in that what helps one passenger’s situation, makes it worst for another. 

“Fixing the problem will require careful, thorough and thoughtful consideration of creative solutions,” Cohn and Belobaba argue, adding, “These are not easy questions, but managing aviation is not an easy task.” 

Tarmac Delay Task Force

The airlines have tried. Following a recommendation by the U.S. Department of Transportation’s (DOT) Office of Inspector General (OIG), Mary E. Peters, the last Secretary of Transportation in the Bush administration, established a national task force on January 3, 2008, composed of airlines (including Continental), airports, and government agencies, including the FAA and TSA – and also consumer groups – to develop contingency plans to deal with lengthy ground delays.

Much of the task force’s initial work was focused on understanding the nature and scope of the problem, which led to the conclusion that airlines, airports, government agencies, and other aviation service providers needed develop their own individual contingency plans, along with ways to better coordinate between responsible parties during these events. 

The task force’s work product was extensive and comprehensive, and included of all types of away-from-gate delays, including those resulting from diversions.

Diversions

Regarding diversions, the task force determined that individual airlines should establish pre-identified airports that would be used where possible, while recognizing that emergency diversions sometimes require the use of unanticipated airports.  Airlines and their code-share partners should have procedures in place to coordinate with those facilities, according to the task force’s findings, and their local stations should coordinate with their individual airport authority, local vendors, and onsite government agencies as necessary.

The task force also recommended that airports should make available pertinent operational information about such things as the availability of gates, ground support equipment, staff, including TSA personnel, as well as local hotels, buses, and medical support, and during a lengthy onboard ground delay, the airline should have procedures in place for deplaning passengers following predefined triggering events or circumstances.

When passengers in the terminal area are impacted during a ground delay, each airline, in coordination with the other aviation service providers as appropriate, should have procedures for responding to passenger needs, including those of passengers with special needs.

The task force also indentified responsibilities of the FAA during diversion episodes, including its need to provide accurate, complete, and timely information to effected airlines and airports. It particularly noted the role that the airlines and the FAA’s ATC System Command Center should play indentifying and prioritizing diverted flights and how the agency’s CDM (collaborative decision making) Diversion Recovery Tool could be used for this purpose.

The role of the Transportation Security Administration (TSA) during these events is also very important. The TSA agreed, and told the task force that it would use the following procedures when a diversion occurs to an airport when its personnel are not scheduled to be present:  

• If passengers are deplaned into a secure area and remain in the secure area, they may re-board the aircraft without additional TSA screening.
• The airport or airline may establish a secure area using procedures in its Airport Security Program or Aircraft Operator Security Program without TSA presence.
• Procedures may be established to allow for the escort of passengers outside the secure area (for example, to vending machines) and return without TSA screening.

Checklists, Simulations and Common Sense

Of course plans aren’t enough if they aren’t followed when needed. When it comes to unplanned flight disruptions, such as diversions, I believe the principal players need to rehearse their irregular procedures to ensure to proficiency, and to discover unforeseen problems, just as flight crews do.  

There was evidence that some things broke down at Rochester that night. For example, Steve Leqve, Rochester’s airport manager, insists that Flight 2816’s passengers could have come into the terminal at anytime during its forced stay, and said the decision to leave passengers on the airplane “was strictly Continental dispatches.”

Greg Principato, president of the Airports Council International-North America, wrote on his blog (“Enough Already,” August 11th) that there were clean restrooms and vending machines available a sterile area of Rochester’s terminal. And, “The notion that the absence of TSA screeners caused this is also nonsense; the people could have been let off and remained in the secure area of the terminal.”

The TSA  statement on its blog on its blog explaining that it doesn’t make decisions on whether or not passengers can deplane. “We do, however, have the ability to recall our officers and open a checkpoint at the request of an airline or airport. No requests were made by ExpressJet on Friday or Saturday. The checkpoint resumed normal operations at 4:30 a.m. on Saturday.”

Continental has accepted some of the blame, and issued a statement saying it is “working closely with ExpressJet to review and quickly resolve the issues surrounding this extended delay,” calling the service provided to customers on Flight 2816 “completely unacceptable.”

ExpressJet said it will review the “circumstances that prevented the passengers from getting off sooner and will take whatever steps are necessary to prevent this situation from occurring again.”

All flight disruptions are frustrating to everyone involved, and those which are caused by acts of God will continue to happen in the foreseeable future.  Let’s hope we can use an experience like Flight 2816’s to continue learning how to handle them better.