Ask the Captain: Why must window shades be open for takeoff?

— -- Question: Why, on some flights, are the window shades required to be open for takeoff and landing? On the majority of flights I've taken, this isn't even mentioned.

— submitted by reader Hichens

Answer: If a U.S. airline chooses to include the window-shade position in their pre-takeoff and pre-landing announcement, and the FAA (or any other regulatory agency) approves the announcement, then it becomes a requirement for them.

There is some variation between the airlines in these announcements. The FAA requires certain information such as how to operate the seat belt, the location and type of exits, and the location and operation of the oxygen masks. If an airline chooses to add additional information, the FAA reviews it and approves or rejects it.

Regulators of other countries may require that the window shades be open for takeoff and landing which would affect their airlines.

Here are some follow-up questions to recent Ask the Captain columns:

Q: Captain Cox, in a recent column, you addressed, among other safety measures, utilizing the drink cart to block the aisle and the lavatory when the cockpit door is open. On a recent trans-Atlantic flight on a 747, I was seated in the first row of seats behind the cockpit on the upper deck. Many times during the flight the cockpit door was open and the pilots, as they rotated, came out and spoke with those seated in this part of the aircraft with no apparent security mechanism. Is the assumption that if you are flying in a premium class of service that you pose no threat to the safety of the aircraft? Is the apparent lack of security something that should be reported to the airline or to the FAA?

— jasmith1

A: Many 747s do not have carts on the upper deck, making it impossible to use them to block the flight deck door. There are only a few people seated in the upper deck of the 747, unlike the hundreds seated on an A380, thus reducing the security risk. All of the security programs are approved by the FAA and TSA and the flight crews follow them. The details of each security program are not public information, but the flight crew on your flight likely used other security measures to ensure it was safe to open the door.

Q: In a recent column you talked about soft and hard landings. It seems to me I remember that the (Boeing) 727 required a firm touch down to set the squat switches so that the thrust reverse would be allowed to come on. Is this still a problem with more modern jets?

— gurban

A: The 727 weight on wheels switch (squat) switch was very similar to other airplanes built during that time. The firmness of the touch down was not the determining factor in having the switch go from "air" to "ground" mode, it was the movement of the left main landing gear strut. When the strut was fully extended the switch sensed the "air" mode, when it is compressed the switch sensed "ground" mode. A very soft touch down could be made while still compressing the strut and having the switch move from "air" to "ground" mode.

John Cox is a retired airline captain with U.S. Airways and runs his own aviation safety consulting company, Safety Operating Systems.