How English Improves Communication in the Cockpit
Frequent fliers understand just how interconnected the world has become, thanks to common interests and the increasing use of English as the universal language. The ability to communicate without the use of interpreters has revolutionized the business world-and the aviation industry. In fact, after the end of World War II, English became the official tongue used by everyone in the aviation realm. Of course, a Japanese pilot can still speak Japanese when flying in Japanese airspace, but when he flies internationally, he will have to use English.
The International Civil Aviation Organization (ICAO) made the requirement of English proficiency by pilots and controllers mandatory in 2008. The FAA followed by requiring all pilots operating internationally to have the "English proficiency" annotation on their licenses by March 2009.
Does this mean that English speakers can fly anywhere in the world and understand all air traffic controllers and other pilots? Well, sometimes. Keep in mind that most international flights originating in the U.S. will be long and will take place during the late evening. Landings are often made in the early morning, when pilots are undoubtedly tired. Due to this fatigue, any differences in accent will be magnified exponentially. It is quite common for the PNF (Pilot Not Flying), who talks on the radio, to misunderstand a transmittal to the aircraft when it's delivered with a strong accent. I have flown all over the world, but I still have occasional difficulty understanding controllers-even those from other English-speaking countries, such as Ireland, Scotland and England.
Flying in the Pacific and the Far East presents its own problems. For example, I have particular trouble understanding the controllers when flying from Japan to Bangkok, Thailand. The flight path is usually plotted down the Chinese coast, over Vietnam and Laos, then into Thailand. Some radio communication in these countries can be achieved only with HF (high-frequency) radios. Anyone who has used HF radio knows how distorted voices can become. Complicating matters further, aircraft and controllers often use a common frequency, depending on the time of day. As a result, all aircraft flying within a 200-mile radius are probably using the same channel. Getting a call in may take several attempts and can be very frustrating. Combine a strong accent with an antiquated radio, and you'll have the recipe for errors and miscommunication.
There has been a coordinated effort to introduce English as the common tongue for all aviation entities worldwide. While adoption has been slow, concrete improvements in safety have already been realized through the use of a
On your mind
Readers pose their questions on air travel
Q. This spring, we returned from Europe on an Air France Airbus 330-200 and had a very nice flight. We were particularly impressed with how pleasant and efficient the cabin crew was. Less than a week after we returned, AF-447 went down. Partly because of our recent experience, I have done a lot of reading on the subject and came across the term "coffin corner." For a loaded A-320 at, say, 37,000 feet, how narrow is the airspeed between the top and the bottom of the flight envelope? I thought I heard on TV that it was 8 mph, which sounds rather narrow to an outsider like me. I would appreciate any light you could shed on the matter.
Irv Usner, Beverly Hills, Michigan
A. This term refers to the peak or corner in the stall speed/critical mach number chart. Operating outside of the published altitude and weight limits for a specific aircraft puts you in the coffin corner, so to speak. The critical mach number is the airspeed at which the airflow over a specific portion of an aerodynamic shape becomes supersonic and creates a shock wave. When this occurs, the drag coefficient increases suddenly and dramatically increases drag on the airframe. Airliners are not designed to fly at supersonic airspeeds, so when shock waves occur in the airflow over the wing or tailplane, the plane can stall or lose control.
I have looked at the A-320's 1.3G Initial Buffet Speeds Chart. For a fully loaded (165,000 pounds) A-320 at 37,000 feet, the spread between the stall speed and the critical mach number is only three knots (3.45 mph). The 1.3G refers to the extra three-tenths G over the 1G that all aircraft experience in level flight. The extra .3G is added for maneuvering and/or turbulence. Needless to say, most pilots would avoid operating their aircraft with such a thin margin of safety.
If you were to decrease either the weight or the altitude of the cruising aircraft, the spread between a stall and the critical mach number would widen. For example, an A-320 at flight level 330, weighing only 130,000 pounds, would have an 81-knot spread between stalling and exceeding critical mach.
There are just two situations in which any aircraft could find itself in this predicament, and both of them are weather-related. One could happen if a pilot were attempting to climb over a thunderstorm, misjudged the height of the cell and tried a last-ditch effort to climb higher. The other might happen if the pilot were stuck in heavy turbulence and attempted a climb to circumvent it. This is why we always carry charts to determine the safe operating envelope for our specific aircraft.
Have a question you'd like Chris Cooke to answer in a future issue? Send it to firstname.lastname@example.org.