I reached over to the left of my seat and squeezed the red tabs of the oxygen mask. The mask hissed as the inflatable straps began to fill with air. I pulled the device out of its holder and placed it over my face. Immediately after I released the red tabs, the cup and goggle combination enveloped my head with a firm grip as though the spiny creature from Alien had attacked. The creature attempted to squeeze my prescription glasses into my eyes. I tugged and pulled, wrestling with the entire device in an attempt to reduce my blurred vision. My success was limited.
The electronic “Smoke and Fumes” checklist that I had selected for display on the center screen of the cockpit pedestal was barely legible, perhaps a realistic scenario if visibility were indeed restricted. Fortunately, I was seated in a simulator. Smoke was merely stated by our check airman rather than replicated. Like most of my colleagues, I was not especially fond of this training exercise. It was good medicine that tasted horrible. Later, I reflected on the scenario.
Based on my experience as a critical-incident stress management volunteer with the airline — a strictly informal analysis — many of the incidents that garnered the attention of at least a phone call to the pilots involved concerned some form of smoke event in the cabin or cockpit. This is not to say smoke was a typical inflight emergency but rather that it seemed to have a more profound effect on the psyche of my fellow crew members. Why exactly?
The answer to the question may lie in other emergency events, especially those events that are practiced routinely on every recurrent training cycle. Consider an engine fire, for instance. I’ll use the 777 simply because it’s the airplane I fly and because its sophistication is a reflection of how modern-day systems function in an abnormal situation. An engine fire in a 777 becomes a pragmatic event.
First, a good, old-fashioned engine fire is a situation that most likely will take care of itself once its source of energy is no longer available. And the source of energy for almost all engine fires is fuel. Bottom line: The fire will blow itself out when it is no longer supplied with fuel. For the most part, the guts of a jet engine don’t include a whole lot of combustible materials. That being said, an engine fire is not a casual event by any means. Its urgency requires the use of “memory items.” These are initial actions of a procedure that are considered critical for pilots to perform without reference to a checklist.
Immediately after takeoff an engine malfunction adds a level of difficulty. Airplanes are certified based on their performance of having a complete engine failure at a critical moment in time. Introduce a fire, and the level of difficulty becomes even more problematic. If an engine fire is not addressed in a timely manner, the potential for compound issues becomes a serious concern. As opposed to other takeoff emergencies, we are trained to proceed with the engine-fire memory items at such time that the controllability of the airplane is firmly established and a minimum altitude of 400 feet has been attained. So what are the memory items?
In this circumstance, a flow pattern is utilized. Flow patterns are movements that guide the eye and the hand in a logical manner. They are not only an assistance to cockpit preflight inspections but also a tremendous aid in recalling checklist items not used on a regular basis, especially during the heat of the battle in an emergency. As an example, the preflight inspection of the overhead panel involves a logical progression that sweeps each section from top to bottom, rather than random examination of switches from one part of the cockpit to the other.
For an engine fire, the autothrottle associated with the affected side is disabled by turning off the switch located on the eyebrow of the glareshield. Once the autothrottle is disabled, the nonfunctioning thrust lever can be moved to the idle position. Just behind the thrust lever on the quadrant is the fuel cutoff switch. The switch is moved to the off position, officially discontinuing the supply of fuel. Next, just behind the fuel control switch is the fire handle. Assuming a fire is still occurring, the fire handle will be illuminated red. It is pulled, cutting off electrical power, hydraulics and bleed air from the Âengine. If, after these particular checklist items are completed and indications are still present that a fire exists, the fire handle is rotated, discharging one of two halon bottles in order to extinguish the flames.
Beyond the memory items immediately accomplished, the remaining portion of the checklist involves housekeeping chores. Mostly the objective is to return the airplane safely back to earth with very few procedures that differ from a nor-mal landing.
The 777 employs a TAC (thrust asymmetry compensator). The TAC takes the awkwardness of operating with asymmetric thrust and almost completely eliminates it by automatically applying the appropriate rudder pressure. The sophistication of the electrical system and the autopilot even allows for a CAT III approach down to 300 feet RVR with one engine inoperative.
If the checklist is followed with minimal errors, the procedure for an engine fire practiced in the simulator is a systematic event. It has a high probability of a successful outcome. But smoke entering the cockpit or cabin is an unknown. This is not to say the situation isn’t controllable. By methodical use of the checklist, the problem can be solved and the threat eliminated. But the checklist involves a lengthy procedure that requires a certain degree of troubleshooting to determine the source of smoke. If the troubleshooting process fails, the only alternative is to evacuate the smoke and land ASAP.
While all this is occurring, did I mention the possible reduction in cockpit visibility, notwithstanding the cumbersome mask apparatus that I described in the first paragraph? In addition, communication with ATC, with the flight attendants and with the passengers requires a juggling act of switches. Not having a grasp of switch functionality or a strategy of untypical communication methods could sacrifice precious moments.
Many will recall the circumstances surrounding Swissair Flight 111 on Sept. 2, 1998. Acting as an armchair quarterback, it is easy to reach the conclusion that it was an avoidable tragedy. But that conclusion would be a rush to judgment, not knowing the circumstances. The airline community, if not the entire aviation community, learned valuable lessons from this accident. One of the lessons concluded with modification of smoke checklist priorities.
As a recap, the MD-11 experienced electrical fire and smoke from the aft cockpit ceiling. The source of the electrical issue was determined to have come from the passenger entertainment system, information unknown to the pilots. The crew methodically prepared the airplane for an emergency diversion into Halifax, Nova Scotia.
As part of the process, fuel dumping was initiated in order to bring the airplane below max landing weight. Landing above certified max landing weight could impose structural issues. In addition, approach speeds are necessarily higher, increasing required runway lengths. That being said, airliners are able to withstand landings even at max takeoff weight so long as the sink rate is not excessive upon touchdown.
Unfortunately, the urgency of the situation was not quite apparent. Cockpit instrumentation rapidly shut down, reaching a level whereupon the pilots were unable to maintain control. The MD-11 crashed into the ocean. In retrospect, the checklist language priority should have been written to simply get the airplane on the ground. Although given the severity and rapid spread of the electrical fire, investigators indicated the outcome may have been the same.
A smoke checklist for an unknown source requires methodical adherence to the procedures. Initially, at least on the 777, the procedures involve troubleshooting that isolates one bleed air system from the other. Just by virtue of having to wait while verifying whether the smoke concentration has decreased as a result of the isolation procedure can be a critical factor. The checklist includes a provision that allows it to be abandoned for the smoke removal checklist instead. Regardless, it’s an uncomfortable circumstance that can easily become uncontrollable.
No pilot in any airplane, big or small, wants to be presented with a smoke event. Transitioning the airplane safely to terra firma is always the best solution.
Given a choice, give me the engine fire. I never want to experience a situation that requires use of that damn mask.
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