Plane Answers: How close are airliners allowed to fly?

by Kent Wien on

Welcome to Plane Answers, where our resident airline pilot, Kent Wien, answers your questions about everything from takeoff to touchdown and beyond. Have a question of your own? Ask away!

This question was submitted by Jim,

Hi Kent,

My question concerns how much advance notice pilots get when there are other planes in their immediate air space. In some of my travels, while at cruising altitude, I’ve seen other planes cross paths just below us. Knowing how many planes fill the sky each day and knowing that your reaction time is minimal, I wonder how pilots and controllers work together to keep all those planes apart. Also, what’s the rule on how much distance must there be between planes when on the same route and at intersection points?Thanks Jim,

I know it can be a little disconcerting to see another airplane cross under or zip by overhead just as you look out the window of an airliner.

Air traffic controllers have rules on how far laterally they must keep airplanes apart as well as how much vertical space needs to be kept between them.

For lateral separation, airplanes that are en route–flying faster and further away from the ATC facility–must have at least 5 nautical miles between them. When the airplanes enter the approach controller’s airspace, that requirement goes down to 3 nautical miles. Finally, when the airplane is in the control of an airport’s tower controller, aircraft can be spaced much closer if that controller has visual contact with the airplanes or if at least one pilot reports they have the other aircraft in sight. A good example of this is the visual approaches to San Francisco where airplanes are lined up on final approach for the parallel runways. You would think the airplanes are flying in formation at times.

This visual separation doesn’t apply when airplanes are in the clouds, in which case the controllers keep airplanes spaced about 2 1/2 NM apart, more if the preceding aircraft is a heavy (over 250,000 pounds–757 or larger) and the following aircraft is not. This limitation is a function of the wake turbulence generated by larger airplanes.

But I suspect the airplanes that you’ve been seeing lately have been even closer laterally than that. Because of some technology improvements to corporate jets and airliners, most of the world has adopted the Reduced Vertical Separation Minima (RVSM) standards. This allows aircraft flying above 29,000 feet to be spaced at 1,000 foot intervals. In the past, that number was 2,000 feet apart.

This has actually had the effect of doubling our airspace above 29,000 feet, which allows for more direct routing and the ability for us to get out of annoying areas of turbulence.

Westbound aircraft are normally put at the even flight levels (altitudes) and eastbound aircraft fly at the odd levels. That doesn’t apply to the North Atlantic, where most of the traffic flies westbound in the morning and eastbound in the afternoon. In that case, airplanes are spaced 1000 feet apart which makes for some great views from our seat as you can see from the following video clip:


Have a question for Kent? Ask away and he’ll pick one to answer here on Friday.

Plane Answers: “When did first class become the crew lounge?”

by Kent Wien on

Welcome to Gadling’s latest feature, Plane Answers, where our resident airline pilot, Kent Wien, answers your questions about everything from take off to touch down and beyond. Have a question of your own? Ask away!

Dennis asks:

As one who travels somewhat frequently for business and pleasure, I have taken notice recently of just how pervasive it has become for United Airlines (the carrier I usually fly) to seat airline employees dressed in full uniform (most probably dead heading to the next hub) in the First Class cabin, even though in many cases there are ample seats available in economy. Somehow I get a little offended by this. At the very least, wouldn’t it be a show of goodwill if space is indeed available to upgrade paying customers at the gate and let the crew sit in back? Is this a common practice amongst all airlines? What are your comments on this topic?

Thanks for the question, Dennis.

While I can’t speak for United Airlines, I can give a little background on this practice as it relates to my airline. Employees have negotiated improvements to their benefits as they relate to non-revenue travel and deadheading while at work.
For us, non-revenue coach travel is free for employees with at least five years of employment. If the employee would like to travel in first class, a fee is assessed. In either case, the employee is responsible for the taxes normally applied to airline tickets as well as a separate income tax on this benefit.

Deadheading employees are often used to fill gaps in coverage at other bases or if one of their legs of a trip has cancelled. These employees can put themselves on the upgrade list online or while at the gate.

In both of the above cases, crews are offered seats up front only after all first class revenue passengers and frequent flyer upgrade requests have been met. These seats would have otherwise gone unfilled. Pilots and flight attendant unions often negotiate these benefits, and airlines are willing to use them to attract new employees.

I discussed this policy with a gate agent today and she explained that some confusion occurs when passengers that request to use an upgrade voucher give up and decide to take their originally assigned coach seat during the boarding process. Usually the agents wait for no-show passengers before processing the upgrade requests, and if a passenger elects to take their seat in the back they’re unable to go on board and move that passenger up to first class.

Airlines are hesitant to upgrade coach passengers even with empty seats in first class probably because they don’t want remove any incentive for travelers to pay for that premium seat.

Employees have sacrificed their pay and work rules for the past seven years–often helping their airlines pull through some tough times. I hope you don’t fault them if they’re sitting in an otherwise unused first class seat every now and then.

On a somewhat related note, my Irish friend Ruthann provided me with a story that might just work for you if you’re out of upgrade vouchers:

Several years ago, a sales department (frequent travelling) co-worker of mine was passing through LAX on his way back to Ireland when he decided to try his chances with the AA desk clerk and charm her with his Irishy Irishness. He put on his best leipreachán accent and requested an upgrade to first class.

The lady seemed to flirt with him, and was very happy to upgrade the remainder of his trip to first class for free. It was love at first sight, at least for her. He promised her the world, being the funny, jokey charmer that he is. He came back and boasted to us all about the AA clerk he’d charmed into a free upgrade.

A few days later, he got a long distance call. She had kept his info and phoned him, just to see if he got to Ireland safely…

Several years later and they’re due to get married soon.

So there you go. But you might want to proceed with caution if you don’t have the requisite Irish Irishyness!

US pilots jump ship; love Emirates

by Iva Skoch on

I had no idea US pilots were leaving the country in droves. I guess it makes sense. All the bankruptcies in the US airline business, pay cuts, frozen pensions, eroded job security and increases in monthly flight hours are not exactly benefits of the job.

This Time article, titled International Departures, describes the mood among pilots working in the US as not exactly filled with motivation. Many US pilots have already switched to working for international carriers, where they can still be treated like “upper-level managers, with something they feel has long been missing in the US: respect.”

Dubai-based Emirates, for example, expects to hire 540 pilots this year. Half the applicants are Americans, compared with just 7% of its current pilots. Over the past four years, over 100 US pilots have been lured by Emirates and their generous benefits package, including over 40 days of vacation and guaranteed annual raises.

I wonder what Kent will say about this trend. Any insights?

Should pilots have to compete for your business?

by Kent Wien on

You’ve always dreamt of flying out to a remote lodge in the middle of nowhere in Alaska, but you’re a bit concerned about the pilots. Are they really good enough to get you into that 1000-foot strip? Wouldn’t it be nice to know just how these aviators rank?

Well, the May Day Fly-In and Airshow in Valdez, Alaska has a bush pilot competition that ranks pilots and their planes in their ability to takeoff and land in the shortest possible distances. These airplanes are highly modified to handle the tightest gravel bars Alaska has to offer. And their pilots know how to get the most out of them.

If you’re looking for some experienced pilots to take you to a great lodge, you can’t go too wrong with the Claus family. Dad, Paul, accomplished the shortest takeoff at 19 feet, and his 18-year old son Jay scored a 39-foot takeoff, which was good for 4th place in his class. The Claus family own and operate the Ultima Thule Lodge.

Here’s 18 year old Jay’s 39 foot takeoff:


I think I’m ready to go visit the Claus family and see just WHERE they’re taking this airplane!

Join Kent at Cockpit Chronicles which takes you along on each of his trips as a co-pilot on the Boeing 757 and 767 out of Boston.

GADLING’S TAKE FIVE: Week of August 27

by Adrienne Wilson on

It’s the beginning of a new month, but still the end of the week for us here and with that we bring you some of the week’s best:

5. Pilot Locks Self Out:
This is the kind of story one reads and rubs their eyes in disbelief. Sure it’s humorous, but somewhat scary too. A pilot locked out of the cockpit? How can that be? You’ll need to head over for more details.

4. Sex and Violence, Elk-style:
Iva Skoch wastes no time in making her presence known with this alarming headline. I won’t spill all the details here, but let’s just say its got a something to do with hiking and animal acts. Read further – I dare you.

3. Cape Verde:
I’m giving this plug on Cape Verde the number three spot because we don’t get around to Africa much and it seems like such an amazing place. (Understatement, yes – of course.) Cape Verde is beginning to attract interest according to this piece and you wouldn’t want to be the last to find out why would you? Go check it out!

2. Backpacking in California’s Sierras:
We love first-hand experiences here and Neil does a fantastic job on recounting his trip through California’s Sierras. Complete with photos and enough tips to help you plan your own visit out yonder.

1. Never Heard of:
Great post if you’re the traveling type that likes to wander into places no one has ever been or few people know little about. I know I’m one of them and this list from Budget Travel is worth clipping out and saving for later when an exciting destination where no-one will find you is much needed.