|The New SR MD-11 Cockpit contains||
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|Dual Power supplies
more complex instrument
|Center pedestal in cockpit, showing new viewing screen installed between the left and right flight management system (FMS) control panels. The middle screen allows the aircrew to select various views covered by cameras in the interior spaces of the aircraft. Holes immediately above show location of new standby instrumentation.|
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Vowing never again to lose an airplane to a runaway electrical fire in flight, Swissair is modifying its fleet of MD-11 aircraft to reduce the probability of a spreading conflagration and to improve its aircrews’ ability to cope should such an emergency occur.
In many respects, the carrier’s effort sets a standard for fire protection that challenges the rest of the industry.
The Swiss national carrier’s “Modification Plus” program is now well under way, with work nearly completed on the first of Swissair’s fleet of 19 MD-11 aircraft. Both hardware and procedural changes (i.e., checklists) are involved, although the major cost involves hardware installed in the aircraft to (1) decrease the likelihood that electrical arcing can lead to a spreading fire, (2) provide better information to the flight crew of smoke/fire in vital spaces, and (3) upgrade the airplane’s fire extinguishing capability.
These efforts are a direct outgrowth of the fatal September 2, 1998 crash of a Swissair MD-11, Flight 111 (SR 111), at Halifax, Canada. All 229 passengers and crew aboard were killed, and the tragedy launched perhaps the most expensive and comprehensive accident investigation in the history of Canada’s Transportation Safety Board (TSB). The final results of the TSB investigation are months, if not a year or more away from publication.
Jolted into action
According to Swissair’s Capt. Peter Ernst, the accident struck the Swiss carrier like a gunshot. Concerned about a rising rate of incidents and non-routine occurrences, carrier officials were in the midst of corporate seminars addressing the need for improvements in safety management when the accident occurred. “The participants were jolted away from the endless listing of cost problems, budget restrictions…punctuality reports and others by the explosive report of the hard and dramatic reality of an aircraft accident,” Ernst recounted at the Canadian Aviation Safety Seminar (CASS 2001) earlier this year (see ASW, May 21, p. 9). Ernst related that the minutes of the company’s last safety management seminar were dated September 1, 1998, the very day before the accident.
In the painful period since, Swissair has led the industry in a number of areas relating to in-flight fire protection. For example, it was among the first to replace metalized Mylar thermal acoustic insulation blankets with a more fire resistant material known as Tedlar (see ASW, November 15, 1999, p. 8-9). This product passes the more rigorous test (than the simple vertical flame test) developed by the U.S. Federal Aviation Administration (FAA), involving a combination of radiant heat and direct exposure to flame, to qualify thermal acoustic blanketing in airplanes. Indeed, the FAA has required the replacement of metalized Mylar throughout the Douglas-built fleet. The material has been deemed uniquely susceptible to fire propagation from a small ignition source (see ASW, June 5, 2000, p. 1).
The Modification Plus program marks yet another precedent-setting step for Swissair.
Swissair’s MD-11 pilots were informed of the program’s details in an internal bulletin issued late last year. As Capt. Ruedi Bornhauser, MD-11 technical pilot for Swissair, explained in that bulletin, “The program is based on an in-house study, which has grown out of the SR 111 accident investigation, focusing on possibilities for reducing and minimizing the vulnerability of the aircraft in significant areas and thereby improving flight safety beyond legal requirements.” Bornhauser outlined six major components of the effort:
i Replacement of metalized Mylar with more fire-resistant insulation blankets.
iImproved smoke/fire detection and verification.
iImproved fire fighting.
iGreater separation of electrical power cables and system wiring
iMore fire-resistant connectors for the emergency oxygen system and for the air conditioning system ductwork.
iImproved standby instruments with dual power sources and separate, independent wiring (see ASW, March 12, p. 1).
Those improvements are now being incorporated into the first of Swissair’s fleet of 19 MD-11 aircraft. The need for such improvements was recognized a year after the crash, and the Modification Plus program follows that preliminary listing of needs (see ASW, Aug. 30, 1999, p. 1). The Modification Plus program also formalizes changes to the electrical system configuration of the MD-11 to better separate key wires and to improve system redundancy (see ASW, Jan. 31, 2000, p 1, and Feb. 7, 2000, p. 6).
Additional details and technical aspects of the program were outlined in recent interviews with Bornhauser, regarded as one of the driving forces in the program, and with Willi Schurter, who was called back from retirement to head Swissair’s Post Emergency Organization (see boxes at p. and p ).
Perhaps the most unique feature of the Modification Plus program involves the installation of nine cameras in sets of three. They are being fitted in three areas of the airplane deemed particularly vulnerable to the ravaging effects of in-flight fire: the avionics bay underneath the cockpit, the cockpit itself, and the ceiling area above the first class cabin and galley area. TSB investigators found heat damaged wiring in the upper right area of the cockpit of the accident aircraft. Not only have wires been re-routed and separated for improved redundancy in this area, it is now under the watchful eye of cameras installed in the space between the ceiling panel and the thermal/acoustic blankets on the outer aluminum skin of the airplane.
In many respects, the camera installation reflects the need cited by the UK’s Air Accidents Investigation Branch (AAIB) for better fire detection in inaccessible areas of the aircraft. This finding stemmed from the AAIB’s investigation of a 1998 arcing event in the avionics bay of a United Airlines [UAL] B767 that forced the crew to abandon its westbound Trans-Atlantic flight and divert to London’s Heathrow airport (see ASW,___________).
The heat-resistant infrared cameras being installed in the Swissair jets are connected to a cockpit viewing screen, giving aircrews a real-time “picture” in the event of a smoke alarm. A switch enables the crew to select the view from each camera (see photos at pages ________).
According to sources, the Modification Plus program is costing Swissair about $650,000 per airplane. That implies a total program cost for all 19 aircraft of some $12.3 million. Work on the first aircraft (HB-IWA) is in the final stage. The first test flight is slated for August 2, with Bornhauser and a Boeing test pilot at the controls. FAA certification is expected in the first or second week of August.
Swissair plans to complete work on the remaining MD-11s at the rate of one per month until all 19 are modified.
Searching for standardization
According to Bornhauser and Schurter, the carrier plans to incorporate the upgrades on its fleet of Airbus Industrie aircraft as soon as the work on MD-11s is finished. The carrier currently operates a fleet of (insert number of aircraft here) A319/320/321 and A330 aircraft, and it has the A340 on order.
Even before that hardware work begins, the carrier has been working with Airbus to improve standardization of the checklists to be used in the event of in-flight smoke/fire. According to the latest Bornhauser bulletin:
“Based on several findings of the TSB accident investigation, intensive discussion with Airbus took place. Already a year ago a Swissair delegation was involved in a workshop with the goal to improve the smoke checklist. On the Airbus up to now three different procedures were available for AVIONICS SMOKE, AIR COND SMOKE, and CABIN EQUIPMENT SMOKE. All these procedures are now combined in one checklist procedure similar to what we have with the (MD-11) SMOKE/FUMES OF UNKNOWN ORIGIN checklist. There are still some ‘smoke definitions’ which, due to the different cultural backgrounds (according to Airbus), could not be changed. Therefore, explanations like ‘dense smoke’ or ‘perceptible smoke’ still exist for them.”
In addition to the foregoing, Swissair is evaluating the Emergency Vision Assurance System (EVAS) to enable pilots to see their instruments and to see out the windshield should the cockpit become filled with smoke. The system works by using a custom-fitted inflatable clear-plastic “bag” to physically displace the smoke (see ASW, ____________). The system, already certified for numerous aircraft, recently was awarded Safety Product of the Year at the Paris Air Show. The system was demonstrated to Swissair officials July 18.
One aspect of Swissair’s extensive cockpit rewiring bears mention. The factory-installed tefzel wiring is being replaced with kapton wiring. Kapton has greater resistance than tefzel to chafing, but one of the great “negatives” of kapton is its propensity for “flashover” in an arcing situation. The charred insulation itself can become a conductor, leading to rapid propagation of arcing damage along a wire and from wire-to-wire in a bundle. According to some wire experts, a teflon-kapton-teflon wire, known as TKT, would provide superior protection against arcing. Q
BOX with photo insert of Capt. Bornhauser
‘A huge step forward’
Interview with Capt. Ruedi Bornhauser
Swissair MD-11 Technical Pilot
Interviewed July 17, 2001 at Swissair Headquarters, Zurich International Airport
Question: Capt. Bornhauser, along with representatives of Boeing Engineering and in-house Swissair engineering, you are one of the ‘spiritual fathers’ of the Modification Plus program being applied to the entire Swissair MD-11 fleet. What are the major items of this project?
Bornhauser: First, we are going to install smoke detectors in areas where we think the aircraft is vulnerable. Since we still do not know the root cause of the Flight 111 accident, we looked at the aircraft from a wider perspective. So we looked at critical areas – and these are areas where of course we have a lot of wiring, where we have computers and other avionics – which could be prone to start or propagate a fire. We found that this is at least the cockpit overhead area, the forward galley and first class overhead area, and the avionics compartment underneath the cockpit.
In regards to the avionics compartment, there already are aircraft which have smoke and fire detection systems incorporated, but nothing like this exists in the cockpit or galley overhead area. We also know from experience that you may get false warnings by smoke sensors, and the operational impact of a smoke warning is tremendous. So, from this approach, we wanted to have a camera system to verify that there is really smoke…. We have built several cameras in all three compartments, and here in the cockpit we can select each of the nine cameras individually, and we can see if there is smoke or not. This is really a huge step forward, I believe, and the MD-11 will be the first transport-category passenger aircraft to have such a sophisticated system.
Besides these changes, we now have as well, for the first time, a real fire-fighting capability, which does not exist on any other aircraft. We have Halon bottles in fixed installations in the cockpit and in the sidewalls of the first class galley. If we realize that the smoke is real, caused by a fire, we have a chance to fight it with the 5-lb. Halon bottles (that) we can discharge into the cockpit overhead area. We have two 10-lb. bottles for discharge into the galley overhead area. There is as well a ‘fixed tube’ system where we can distribute the Halon to the most important area in that compartment. This is a major improvement.
Q: In your study in the aftermath of the Flight 111 accident, you found the problems that occurred in the accident scenario were not unique to the MD-11.
Bornhauser: Absolutely true! It wold be completely wrong to say, ‘This is only an MD-11 problem…if that is solved we are all happy again.’ That (attitude) would not be wise and it would not be fair for crews and passengers. It is absolutely an airplane problem, (whether) it’s an Airbus, a Boeing or a former Douglas model. In every airplane you have wires, you have computers, and that is why we are going to study the problem in the other fleets after these modifications. And with the same critical point of view we are going to study our Airbus fleet. We will ask ourselves, ‘Do we have similar areas and points (of possible vulnerability) in this aircraft? Do we have to change something?’
We believe we have to do better than what is done right now, and we already had a success with Airbus. They changed their (smoke/fire) checklist due to our input…. So it is very important to realize that it is a general aircraft problem, not a (unique) MD-11 problem.
Q: Skeptics claim that Swissair is spending money for measures that are not necessary, not mandatory or otherwise required.
Bornhauser: Actually, this is a stupid statement, because you’re increasing the safety of the aircraft. Of course, you have to think about it before you spend a lot of money. But, I’d say it is an investment in safety…. See, airlines are spending money for crazy things in the cabin, like for laptops, e-mail and Internet access – all kinds of things really not needed in an airplane from a pilot’s point of view. This is just marketing driven – you spend more money and it has nothing to do with safety…. You should invest the money rather in increased safety of the transport and not in the entertainment of the passengers.
Q: Does this modification program come out of lessons learned from the Flight 111 accident?
Bornhauser: That is for sure…. In light of the accident, we realized that decision-making is the most important thing for the crew. And we have to give them the means to make a good decision. The Modification Plus program goes in this direction, and it will not stop there. We will assess it for each of our other aircraft, and the philosophy behind the modifications has been incorporated into our manuals and procedures. This is completely independent of the aircraft type. Decision-making in a critical situation like smoke or fire has been reviewed for all fleets…
Q: There seems to be some reluctance to follow Swissair’s example industry-wide.
Bornhauser: One of the major problems today is that all the companies, especially pilots having a job like mine, are all very busy and they do not have time to talk to each other…I believe this (situation) has to be improved. For example, for the MD-11 we have a seminar every two years…and we come together for two days and exchange our experiences. But there is nothing really established between different airlines…and I think that could be improved a lot.
Q: Should similar concepts to your Modification Plus apply to future new aircraft designs?
Bornhauser: Absolutely. I’m convinced that it will work. We have analyzed such ideas as well for cargo compartments and now they have to be brought up to this standard. In the avionics compartment, it is a bit more difficult because of the (cooling) airflow. The problem is to seal the compartment, but I believe we have to face this task. By the way, this is one of the issues the Transportation Safety Board (TSB) of Canada is pressing upon.
Q: The first steps to modify the MD-11 cockpit and to increase the redundancy of essential system wiring date back to January 2000. Why did it take so long?
Bornhauser: It is not that simple. For our (initial) assessments, we knew what we would like to improve. We agreed that we would like to accomplish this together with the aircraft manufacturer, Boeing. Further, we wished to get these modifications certified by the U.S. Federal Aviation Administration (FAA). We wanted to follow the ‘official path’ – a joint venture between the manufacturer, the regulatory agency and us. It took time, and the beginning was a bit resonous (= poetic licence only… from "to resound" : to vibrate sympathetically or 'resinous,' my dictionary (Webster's) says it's an adjective, applying to a "viscid substance..."). (Note: Either would apply to Boeing's response to the Swissair overtures on these modifications. Leave it to you to work out why Boeing was not at all eager to implement these mods or make them available to other operators of MD-11's. They totally rejected the idea of making them Service Bulletins or AD's. He now calls this "politics". An interesting comment). Today, it has developed into outstanding cooperation…. Probably there was some politics involved, but that doesn’t interest me as a pilot. We wanted to step ahead and now we are happy with the achievement.
Q: What are the major advantages of the Modification Plus for you and your pilot colleagues?
Bornhauser: The major advantage is the option of early recognition of a critical situation. Time is the most important factor, as all accidents associated with smoke and fire clearly show. To gain 5, 10 or 15 minutes can be life-saving. So, Modification Plus gives us a higher level of safety. Psychologically, you are aware of having a sophisticated surveillance system in place that will warn earlier than in any other aircraft if something goes wrong. This is definitely a good feeling for pilots, besides the new standby instrument, which will work on its own battery power if the main or the emergency power supplies are effected (lost) or damaged. We go much further than required for certification, but it is our obligation, as we want to learn from the Flight 111 accident and to take corrective measures. I believe it would be fatal if we would not do it. (Tim: The meaning of this statement is still unclear to me). n
BOX with photo insert of Mr. Schurter
Modification Plus ‘A moral obligation’
Interview with Mr. Willi Schurter
Head, Swissair Post-Emergency Organization, Flight 111
Interviewed July 17, 2001, at Swissair Headquarters, Zurich International Airport
Q: As head of Swissair’s Post-Emergency Organization, could you describe your work in the last three years?
Schurter: The Post-Emergency Committee was established right after the accident and is the successor to the Emergency Commission, which actually was a crisis management organization. The Post-Emergency Committee was established by Swissair to insure that…the attention required by an accident is given full priority.
Q: What are the major findings of your team?
Schurter: They are not much different from what the Transportation Safety Board (TSB) of Canada has found so far…. But, obviously, we have tried to establish much faster than the TSB some conclusions that we could draw and (to) initiate actions. It was quite clear early in the investigation that it will go on for a long time, because it is a very complex accident. We considered the time to be too long to wait for the report and only then to initiate corrective actions. That would take something like five years in the end, between the report, which…will come out sometime next year and if you then start to initiate actions it will be the year 2005!
We had to assume…that a major fire was the initial cause for the catastrophic failure of the airplane…. So we were looking at things that in the short time period the crew has in case of a fire on board to assure the safe landing of the airplane.
We equipped the aircraft with fire detecting sensors and fire extinguishing systems, in addition to those already on the airplane. We are installing an improved version of the standby instruments and, thirdly, we are making sure that we have proper segregation of critical wires. Of course, at the same time we also are doing all the Airworthiness Directives from the FAA, which were caused or accelerated by the TSB findings.
Q: Looking at the re-routing of essential power bus feeders, does this mean the aircraft did not have adequate redundancy before?
Schurter: Obviously, you may improve any design. It is our obligation to learn from what happened. Nobody, me included, claims that the aircraft was not up to specification or (the) certification level.
Q: So the new wire separation is a result of your analysis of the contributing factors that may have played a role in the SR 111 accident?
Schurter: We still don’t know exactly if this was the case, but we wanted to make sure it will not play a role in a future accident or incident.
Q: Critics say it is just the ‘pleasure of Swissair’ to make these modifications.
Schurter: I don’t think it is the ‘pleasure of Swissair.’ It is merely a need that we have identified. We believe our modifications are worthwhile. We believe we have a responsibility and a moral obligation to do this for the Flight 111 victims and their families, and certainly for our customers and crews. n
Photo: avionics bay
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Caption: Camera installation in avionics bay of Swissair MD-11. View is looking aft; camera is shown facing forward. Another camera in the bay is located forward, facing aft.
Photo, overhead CB panel
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Overhead circuit breaker (CB) panel in cockpit. This is the area where fire damaged wiring was found on the accident MD-11. In the original factory installation, all wires entered the CB panel on the right. Note now the clear separation into two bundles of system wires, one right, the other left. To the immediate left of the elevator control cables, note also two power feeder cables, running separately, not placed together as in the factory installation.
Photo, cockpit overhead, right side
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Caption: Cockpit overhead area, right side, where fire damaged wiring and materials were found on the MD-11 accident aircraft. The thick gray line is a power feeder cable. Before the Modification Plus alterations, all these power and system wires and cables were in one thick bundle.
Photo, camera close up
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Caption: Close-up view of one of the infrared cameras installed in the overhead area above the first class cabin, looking forward and able to observe wiring running into the first class galley. Note the heat-protected lens.
Photo, cockpit looking aft
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Overhead view of cockpit, looking aft with ceiling panels removed. At lower right, note doorframe of cockpit entrance. The arm-thick tube running across this space is the emergency oxygen line; factory-installed metalized Mylar insulation was replaced with more heat-resistant material. Similar treatment was given to air-conditioning system ducting, shown at right. Separation of three main power supply lines, in middle above, was increased. Not as clear in this black and white version is the separation into left and right runs of wire bundles. Note in particular the necessary proximity of the oxygen line to the wiring (sr111 fire area) on the left of the photo. This would have been similar in unmodified aircraft.
Photo, cockpit center pedestal
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Center pedestal in cockpit, showing new viewing screen installed between the left and right flight management system (FMS) control panels. The middle screen allows the aircrew to select various views covered by cameras in the interior spaces of the aircraft. Holes immediately above show location of new standby instrumentation.
Photo, standby instrument
Insert 3 X 3 photo here
Caption: Standby instrument being retrofitted to Swissair’s MD-11 fleet has been described as a “mini-PFD” (Primary Flight Display). It has dual power sources and separate wring independent of the PFD. This “Secondary Flight Display” is the same system being installed on Federal Express MD-10s.
Photo, cockpit center pedestal, close-up
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Close-up of viewing screen showing actual picture of the camera’s view of the area over the first class galley. Note control switch at left. The crew can select “cockpit,” “galley” or “avionics” bay, and any one of the three cameras in these locations.File: cover 27 July 01 (AIR SAFETY WEEK)
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