The airport in Juneau, Alaska

Factual Questions
1

(Y’know, as opposed to Juneau, North Korea. :p)

I was in Alaska last week on a family trip, including fishing for salmon in the Copper River delta. Our flight to Cordova (on a standard jet airliner) stopped in Juneau and Yakutat.

The approach in Juneau was rather alarming. We’re coming in at an apparently normal angle and speed, and then, suddenly, at what felt like maybe a thousand feet off the ground, directly over a neighborhood, suddenly the 737 banks sharply, makes a hard turn, levels out, drops fast, and lands quickly.

And I’m like: :eek: WTF?

Then, on the departure, we do the normal taxi, accelerate, lift off, routine — and the aircraft’s nose angles up much more steeply than seems normal, like we’re desperately trying to get into the air before slamming into something.

Now that I’m home, I’ve looked into the geography of Juneau a bit, and the city is ensconced in sort of a bowl. Obviously, that makes designing an airport quite a challenge. And the approach, for someone not expecting it, was, like I said, fairly unsettling; the takeoff likewise.

My questions:

How much of this was my imagination? Is landing and taking off in Juneau as extremely different as it felt?

And how dangerous is this airport, really? Do they mandate specialized training or experience for airline pilots before allowing them to navigate the airspace?

*Obligatory footnote: Alaska was gorgeous. I saw only the tiniest sliver of it and I would go back in a heartbeat.

2

Missed the edit window:

Did I mention it was sudden?

:rolleyes:

3

Probably no worse than the now closed Kai Tak airport at Hong Kong. Airplanes had to come in alongside the mountains and aim for a target on a hill. Once they were in sight of it, they had to make a sharp turn and hard descent to land. Crosswinds there were also notorious - this short video clip shows a 747 all but hovering over the runway to straighten out after the turn and land.

This longer one with sound shows a variety of perspectives

4

I’ve flown there (and rented a C-172 for sightseeing) and it is indeed a daunting location for an airport. This chart is not especially clear on terrain heights, but within 5 miles of the field the mountains rise to something like 6000’.

Depending on wind and weather, it certainly could be quite challenging - and Juneau gets plenty of wind and bad weather (T-shirt slogan seen there: “Juneau rain festival - Jan 1st thru Dec 31st”). What you need is an IFR pilot to tell you the details of flying approaches to JNU.

5

I think you just experienced the difference between maximum-rate-of-climb and maximum-angle-of-climb. I know how it works in small planes; someone will be along shortly to explain the big iron.

If there’s any sort of physical obstruction beyond the end of a runway, you want to take off at the steepest angle the plane can handle. Push the throttles forward, pull back on the stick, and watch the airspeed. Keep the airspeed at a certain value (known as V[sub]x[/sub]) and you’ll be climbing at the best possible angle.

Here’s where it gets a little counter-intuitive. Once you’ve cleared the obstacle, you can ease off the stick a little and let the nose come down. The airplane will pick up speed, and that additional airflow over the wings will make it climb faster (in terms of feet-per-minute). The velocity for maximum rate of climb is V[sub]y[/sub].

Most runways don’t have have obstructions, so the planes climb out at V[sub]y[/sub]. At Juneau it probably was steeper, but it’s nothing to worry about.

6

IANAPilot, so take this for what it’s worth. It’s fair enough, I’d imagine, to say that some airports are more challenging than others, but none are “dangerous” by any meaningful definition of the word. All landings, everywhere, are within the capabilities of the pilots and the machines they fly.

As you’d imagine, pilots don’t just look out of the window and say “Ah, hell, should be OK. Let’s give it a go.” :wink: The details of landings and takeoffs are planned in detail according to regulations. Factors that may affect the way a takeoff or landing is performed include (but aren’t limited to): load (fuel, cargo, passengers - probably in that order), runway length, field elevation (higher altitudes provide less lift for the wings due to the lower air pressure), local obstructions like mountains and buildings, crosswinds, rain, snow and so on.

If, in the course of flight, some factor such as weather changes to the point where the regulatory requirements can’t be met, the plane can’t land on that runway.

The takeoff that surprises me every time is London Stansted. In this case it involves a steepish climb and sharp turn to take the engine noise away from towns as quickly as possible.

7

Juneau is a challenging airport: “… its latitude, terrain, weather and heavy air traffic create challenging conditions,” as quoted in the article “Flying Leap” by Paysha Stockton in the Juneau Empire 12 Aug 1998 (link). This is why, for example, flight tests of the GPS Wide Area Augmentation System were conducted in Juneau as early as 1998.

For a picture, try this.

8

It works a bit differently in large aircraft. Not that they don’t have max angle and max rate of climb speeds.

In a large aircraft part of its certification process with the FAA or other governing bodies is proving take-off performance. They must be able to suffer an engine failure at a critical point during the take-off roll (referred to as the V1 speed) and from there, take-off and maintain a certain angle of climb*.

The required angle of climb is not normally achieved by flying the best angle of climb speed! Why? Because the extra time taken to accelerate to the best angle of climb speed means that the overall climb angle achieved from the take-off point is less than if a slower speed is maintained. The minimum climb speed that is flown with a failed engine is referred to as V2.

Once certified in this way, an airline operating this type of aircraft produces take-off charts for all of the airports it operates out of. These take-off charts allow the pilots to work out a maximum take-off weight that will allow the aircraft to meet the minimum performance requirements for the particular airfield.

All of this is done assuming a failure of the critical engine at the most critical time during take-off, so with both engines operating, performance is very good and obstacle clearance is not an issue.

What I think the most likely cause of the steep departure climb in the OPs case is that the aircraft was probably at a lower weight to meet the take-off performance requirements. At this lower weight, with both engines operating normally, it performed better than usual which resulted in a steeper than normal climb.

*This is not quite correct, it must actually maintain a certain climb gradient relative to the ground

9

Thanks all.

And :eek: to this.

10

Here is the Approach Plate for a GPS approach to runway 8:

(Warning - all links are PDFs)

http://www.fboweb.com/dpp/01191RV8.PDF

You can see exactly how the approach is designed to avoid the terrain surrounding the airport. Most airports have these approach plates for every runway and a variety of “scenarios”. They provide all of the information the pilot needs to safely land. There are also departure plates to detail various take-off procedures.

Some other plates for Juneau Intl:

LDX Runway 8 Approach

CINGA THREE Departure

11

Need help eating your catch? My local grocery store has salmon for $8.99 a pound. Every so often, they will get in “Copper River Salmon” and it is $28.00 a pound, and we buy as much as we can afford. Mmmmmmmmmmm. :cool: /hijack

12

I meant to address this but didn’t.

Passengers perception of what an aeroplane is doing is generally quite poor. It is a standing joke amongst pilots that a missed approach or aborted landing of an airliner is reported in the newspapers as a “vertical climb” followed by a “90 degree banked turn.” This is simply not the case but it can feel like it when you are cooped up inside an aeroplane and unable to see whats going on outside. Even when you can see what’s going on outside, people with little experience of movement in three dimensions often missinterpret what is happening.

It is highly unlikely that your B737 got to anything more than 30 degrees angle of bank. It might have felt sudden, and it might have felt steep, but only because you are not used to having your body tipped over at an angle like that.

It is also unlikely that the aircraft descended at any more than the 3.5 degree descent portrayed on the approach plates linked above.

Most likely what you experienced was an approach that included some manoeuvering relatively (1000’ instead of 3000’) close to the ground. Your perception of speed and attitude in this situation is unusual and inaccurately interpreted as extreme.

When I was learning to fly, a 30 degree banked turn felt steep. Sometime later that felt normal and a 45 degree turn felt steep. Then that felt normal and a 60 degree turn felt steep. Eventually I got to the point that i could be upside down and it all felt somehow normal. The vast majority of people never get beyond the stage where 30 degrees feels steep.

Having said all that, I don’t discount the possibility that your pilots made a hash of the approach and your aeroplane did what you described.

13

I’ve read that U.S. military pilots flying in and out of Baghdad have to drop sharply when descending, and climb quickly when ascending, to avoid the risk of ground fire. Not a fun ride for passengers.

14

NAF Adak (Alaska) was another place that was said to have a steeper climb out than usual, due to terrain. (And Adak has crummy weather, too.)

San Diego’s Lindbergh Field, within a half mile of the San Diego down town area, provides an interesting view while coming in for a landing. I swear it seems as if the plane is lower than some of the high rises, and your can look into someones office as you pass by (and wave howdy). Weather is not usually an issue, though.

15

The approach is similar to the approach in Eureka, Calif. They do a very steep dive down a mountain canyon and turn sharply to the left at or near the bottom and land quickly. It is breathtaking.

16

Flying into Yeager Airport here in WV has been described many times by pilots as “like landing on the deck of an aircraft carrier.” I thought that was exaggerated until a fellow who used to work with me said “Nope, it is like landing on an aircraft carrier! I’ve done both and I think the aircraft carrier was easier.”

Here’s what Wiki sez: Yeager Airport - Wikipedia

And seeing who it’s named for, it doesn’t suprise me :eek:

17

Depends on which runway is used in Adak and the direction of take-off. When I was a young Seabee, I was stationed on Adak and was in charge of the airfield lighting. Both runways have approaches over water; the other end is a bit more problematic. There has been at least one plane that has crashed on takeoff there and its carcass still remains on the mountainside as a reminder.

Re: Juneau. It is a bit disconcerting to land there and the approach is as the OP states, with a quick bank to the left. Just before the bank, one wonders if there is an airfield there at all, as all one sees out the windows on the left is mountains and trees, and out the right is just water. At least Juneau now has GPS so planes can land in marginal weather. Downdrafts, updrafts, wind, rain and fog are the norm in Southeast Alaska.

18

Here’s a really interesting approach on video.

This is a 757 on approach to the airport in Tegucigalpa Honduras. Honduras airport is at the bottom of a bowl. The pilot will fly along the ridge of the bowl, getting to about 50’ above the ground. At the edge of the bowl, the pilots starts a very steep descent in order to hammer it on to the relatively short runway (for a 757 anyway) 6100’ at 3300’ elevation.

Video taken from the ground.

Video taken from the cockpit. You can hear the ground proximity warnings (computer voice calling out distance above the ground) followed just before landing by sink rate warning and stick shaker, indicating that the airplane is just about to lose lift and fall out of the sky (in fact, it is kind of falling out of the sky at that point).

19

Dammit, qwest, you beat me to it. My dad was sent to Honduras once while he was in the Air Force and told us about that airport. Yikes!