Flying on the Boeing 777
Thursday, 25 October 2007 05:47
Dear Captain Lim,
What happens when the computers fail at the critical moment? So, you still need human beings to save the day! Pilots are the back ups to machines. Hence, aircrew must undergo a thorough course in order to perform this task."
I have a few queries with regard to your FAQ on Autopilot/ILS.
In FAQ “How does a pilot execute an auto landing during bad weather in a Boeing 777?”
"If a pilot wishes to manually fly the ILS to hone his flying skills, he is restricted to fly to a minimum of 200 feet above ground level and a visibility of 550 meters. Beyond that, he must seek the help of the machine! In other words, the airplane must be auto landed with the help of computers.
1) Does this mean the airplane must be auto landed or auto fly BELOW 200 feet?
2) When computer fail below 200 feet, pilots have to back up the machines. Why pilots are not allowed to fly below 200 feet on a normal day to hone his skills when the circumstance of a computer failing below 200 feet arises?
3) Are pilots officially being allowed to fly under 200 ft manually?
In FAQ "Are some pilots that skillful in flying the Instrument Landing System",
"When the airplane is perfectly aligned with the runway centerline, it does not mean that the airplane is performing an auto-land. If a pilot is not qualified or the runway is not certified to accept auto-landing, he merely allows the autopilot to fly the plane up to 200 feet above ground level and then disengage the automation. He would thereafter *hand fly* the plane until the touch down on the runway."
4) Why is it in this case that a pilot is allowed to fly below 200 feet?
1. This paragraph is stated in the context of an ILS approach in IMC – meaning total cloud cover and the pilot cannot see anything ahead. On a Cat 1 approach, the lowest height the pilot can hand fly the plane is up to 200 feet. Yes, below 200 feet in IMC, only a qualified pilot rated on auto-landing is allowed to continue with the landing (with the aid of the computer of course – as no human can safely fly the plane to touch down when he can*t really see the runway!)
2. A pilot can manually fly below 200 feet only if the weather is fine and the visibility is good. So when the computer fails below 200 feet, he takes over and flies by looking out and not on the instruments anymore. If he cannot see the runway because of poor visibility, he must abort the landing and go around.
3. As mentioned above, pilots are allowed to fly below 200 feet manually on a Cat 1 ILS approach only if they can see the runway (In VMC and not IMC)
4. Only a person qualified to perform auto-landing can legally use the automation to land the plane by the aid of the computers below 200 feet. If not, he must disengage the automation and fly the plane manually ONLY if the weather is fine and the visibility is good. In this case, he has not breached any rules. He did not make use of the automation (because he is not qualified).