Long Beach Division

Flight Operations Bulletin


ATA: 01-00

Bulletin No. MD-11-99-04


Applicable to: All MD-11 Aircraft





Following the tragic crash of an MD-11 last September, The Boeing Company has been conducting exhaustive reviews of various aspects of the design and operation of the airplane, including our recommended smoke procedures. While the cause of the accident is still unknown, and The Boeing Company is not sure which procedures the flight crew used, several operators have requested that Boeing review the existing procedures, as well as possible alternatives.


I. The Smoke/Fumes of Electrical, Air Conditioning, or Unknown Origin checklist procedure developed for the MD-11 is derived from several DC-10 checklist procedures. It was designed to reduce crew workload while trying to identify the source of smoke or fumes. The smoke switch used in this procedure will isolate and de-power one electrical bus and one air conditioning system in each position other than NORM. This will quickly accomplish the same multiple functions that the flight engineer would do in a DC-10 during isolation of electrical or air conditioning smoke or fumes. It must be stressed that this switch consolidates the many steps that the flight engineer has done for many years in the DC-10 procedures.


II. If an electrical malfunction results in a fire, isolation and de-powering of the source will not necessarily extinguish the fire in an MD-11 or a DC-10 or any aircraft. In the MD-11, the smoke switch can be used to isolate (or IDENTIFY??) electrical components, and may do so before smoke and/or fire becomes a threat. It cannot be used to prevent all of the possible hazards that may occur as a result of electrical short-circuiting.


III. The decision to perform the Smoke/Fumes of Electrical, Air Conditioning, or Unknown Origin procedure must be made by a pilot (usually the captain) based on the circumstances of an event. Depending on the nature and severity of the smoke or fumes, the proper execution of this procedure could be lengthy (up to thirty minutes or more). The flight crew must be careful not to move through the different switch positions too quickly, or a source of smoke and/or fumes might go undetected. On the other hand, the more time spent in one position, the longer it will be before other potential sources are isolated. The crew must use all possible resources, including the cabin crew, to quickly determine if any switch position makes a difference in the situation. The flight crew must also be aware that if serious short-circuiting has occurred, complete isolation of a bus may not be possible. Additional troubleshooting, such as pulling circuit breakers if the affected circuit can be identified may be necessary.


IV. If an event occurs while the aircraft is in a reasonable position to land, the flight crew may elect to use alternative procedures such as unpowering all non-essential electrical or air conditioning systems. For example, this could be done by placing the electrical system in MANUAL, tripping the engine generator bus relays, and opening all AC and DC bus tie relays. This would put the aircraft on Emergency power and isolate all but the battery bus and the left AC and DC emergency busses. If desired, the ADG could be deployed and ADG ELEC selected to provide power to the battery charger and the right AC and DC emergency busses. Boeing is considering publishing this as an alternative procedure but has yet to propose this because of the many factors which might be involved in the decision of which action to take. The captain would have to assess each situation to determine which procedure might be more appropriate. How close is the nearest suitable airport? Is Fuel dumping required? Is there a confirmed fire? The list of variables is too great for the manufacturer to be able to develop one single procedure that would be the best for all possible scenarios. Based on experience and sound judgment, the captain must use aircraft system knowledge and a thorough understanding of the situation to determine the best course of action.


V. As a supplement to the existing FCOM procedures, here is some advice that the Boeing Company can give:


A. Consider using the Cabin Bus Off switch immediately if there is a reason to suspect a specific cabin component, such as a galley, lavatory, lighting, or the passenger service units. Continue with the Smoke/Fumes procedure if needed.


B. Consider navigation, communication, and fuel dumping requirements before eliminating major sources of electrical power through alternative methods.


C. Consider using every available resource, including the cabin crew, in attempting to determine if a fire exists, or to determine if the smoke or fumes are dissipating.


D. Analyze the situation and determine if an emergency landing is necessary. If so, don't delay to dump fuel if a runway of sufficient length is available. As the manufacturer, Boeing has demonstrated landings at maximum takeoff gross weight. The structural placard does not even require a hard landing inspection if the touchdown sink rate is less than 6 feet per second at these weights. Stopping distance is the only real concern. But even then, consider whether you would rather be on the ground or in the air.


E. If it has been confirmed that there is/was a fire, it must be dealt with immediately. Direct resources to fight the fire and/or ensure that it does not rekindle. Prepare for a landing as soon as possible, with a possible emergency evacuation. Determine who will fly the airplane, talk on the radio and make landing decisions, and decide who will direct the fire fighting duties. One person cannot do it all. Maintain responsibility and control, but delegate duties. Have a plan. Descend to as low an altitude as possible considering fuel and terrain.


F. If there is smoke without a confirmed fire, what is the impact? Is it incapacitating? Does it impact visibility? Could it create an emergency, even in the absence of a fire (an overheated motor)? There are many unknowns when smoke is detected; one thing for sure is that smoke is NOT normal. Therefore, Boeing advises that anytime smoke has been detected and the source cannot be POSITIVELY identified and eliminated, the aircraft should be landed as soon as possible. Consider an emergency descent after a landing decision has been made.


G. Has there been any damage as a result of smoke or fire? Following an event where smoke or fire has been confirmed, there is the possibility of loss of intended function of some equipment. The loss of function might be major or minor depending on the nature of the event. However, it might not be possible for the crew to anticipate the results of such events, and the indications may vary with time. Therefore, as the manufacturer, Boeing recommends that the aircraft should be landed as soon as possible following any event in which a fire has occurred, or in which an electrical malfunction has been identified and cannot be completely analyzed by the crew to include its impact on other systems. Consider an emergency descent after a landing decision has been made.


VI. The Boeing Company has spent many months considering whether the existing procedures for smoke and fumes identification and isolation are adequate and has concluded that the current procedures are appropriate. A review of all previous in-service smoke incidents has confirmed that the vast majority could have been isolated and controlled using the existing Cabin Bus Off/Smoke switch procedure. However, circumstances associated with specific events might require a flight crew to use judgment in modifying or tailoring procedures.


VII. The Boeing Company has also determined that the industry should consider issues that have been raised in the aftermath of the SR-111 accident. Crews must be given sound advice about analyzing specific situations and using judgment in determining the proper course of action. Each situation will be different, and a canned solution may not be possible. Here are some topics that Boeing feels are appropriate for further consideration on an industry-wide basis:


A. Are there established training programs for fighting in-fight fires? Is there guidance available from fire fighting professionals?


B. Are in-flight fires different from ground fires? What is the effect of cabin altitude? Should the cabin altitude be raised during a fire to reduce the amount of oxygen in the cabin or is that insignificant?


C. Are procedures in place which would involve using the cabin crew in the cockpit?


D. Do crews have a fire fighting plan? Is there a designated fire marshal? If you have an in-flight fire, it's too late to develop a plan.


VIII. Boeing will forward the recommendations in Paragraph VII to the appropriate regulatory/safety agencies.

Should additional information be required, please submit your inquiries through your local field service representative or to Boeing Long Beach Division, ATTN: Flight Operations Customer Service, 3855 Lakewood Boulevard, Mail Code: D094-0026, Long Beach, California 90846-0001, USA, fax: (562) 593-3471.





T. J. Melody

Senior Manager/Chief Test Pilot

Experimental Flight Operations

& Customer Service



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