Just one pilot's attempt at taking an interesting picture every trip, often with a story to go with it. Come along for the ride.

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Friday, April 25, 2008

Plane Answers: How close are airliners allowed to fly?

Every Friday Gadling I try to answer a Plane Answers query. The questions coming in have been great, and I've noticed that some of you have submitted a few. The most often asked question has been about my path to this job, and I plan on writing that up soon, but it's probably going to take a bit more time than, say, this weeks question regarding how close airliners are allowed to fly.

I'm sure passengers are a little uncomfortable when they see another airplane outside the window so close. But keep in mind, for that airplane to be there, we usually know about it up front. I'll probably write about how TCAS (Traffic Collision Avoidance System) has really improved air travle safety in a future Cockpit Chronicles.

I have just two more of the Cockpit Chronicles posts to catch up with and then I'm off to join the family in Germany where they're visiting my mother-in-law. Believe it or not, I really like her! Both Linda and I have been very lucky in the in-law department.


Neil said...

Great post Kent! I have a question that I think fits better over here. What is the minimum distance permitted between two runways that are operating parallel approaches? I heard somewhere that it is 1000ft, but looking at pictures like this www.tinyurl.com/469tvy or this www.tinyurl.com/4vggxd, suggests that 1000ft is not the case.

Looking forward to the article on TCAS, I think it is an amazing piece of technology.


ps Have a great trip!

Kent Wien said...

Great question Neil.

I linked to one of those pictures over on the Plane Answers page. Thanks for that!

For flights to land on parallel runways in IFR conditions (in the clouds, essentially) they have to have a separation of at least 1,035 metres (3,400 feet), which was the distance approved by the International Civil Aviation Organization.

For VFR flights I came up with this link:


So it look like you're right. They can be REALLY close. Under 500 feet even.

Oh, and no, that wasn't my brother flying the heli when the moose attacked. It was a good friend.

See ya, Neil!

Neil said...

Thanks Kent!

Anonymous said...

The last time I flew over the Atlantic, another jet passed us (I think) 1000 feet higher up, and going just slightly faster, and slightly off to the side. It was close enough that I could tell what company it belonged to. And then, after crossing the ocean, the airplane was put into a hold somewhere over upstate NY, and looking out the window as the plane banked, one could see other planes at lower altitudes crossing over the same navigational fix, going every which way.

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Exeter, New Hampshire, United States
Grew up in Alaska, went to high school and college in Washington State. Commercial pilot since 1990.

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