Wind shear in Denver
 

Last week I was on UA from IAD-BOI, connecting in DEN. As we approached DEN, the pilot advised that due to thunderstorms near the airport, we would have to circle awhile until the weather cleared.

We were finally cleared, began the final approach. About a 1/2 mile before the runway, the plane started dropping rapidly, like the initial drop on a rollercoaster. For about 15 seconds I thought we were going to smack into the ground. The pilot gave full throttle to the engines and we started to quickly climb. The motion in the cabin was severe enough to start a wave of airsickness throughout the aircraft.

When we finally got up high enough the pilot advised that we "missed the approach" due to wind shear and that this type of weather occurs frequently in the summer afternoons around DEN.

For the frequent DEN flyers, have you experienced anything like this? If so, maybe I'll connect in ORD for my next trip!!

Have had that happen for a couple of seconds in duration before, but not 15 seconds.

Very common to get some nasty bumps and jolts in the late spring through early fall in DEN. Usually those things happen over the mountains or right along the foothills, but not uncommon coming from the east.

The little-known thing about Denver International Airport is that it was built in tornado alley. You'll note that nearly every restroom has a yellow "Tornado Shelter" sign at the entrance.

Have connected thru DEN a number of times unfortunately, and just your basic turbulence sufficient to have FA's sit down.
Never more than couple seconds drop in altitude.

Actually think Vegas is normally worse.

When it gets bad, time seems to slow down.
Sure you meant 15 secs, or more like 5 ?

When everyone gets quiet, then maybe some surpressed screams, thats when its more like 15 secs.

We had a couple of 1-3 second drops coming in around lunchtime today. A few people went quite quiet, but most people were just trying to hold onto their drinks ...

I flew DEN-ORD on Monday evening. Shortly before we took off, a line of storms moved through the area. Listening to Ch. 9, the ATC was advising every plane that took off of wind shear warnings. They were then following up with every flight asking them if they experienced any wind shear. About 50% said they did but it was minor. Our UA flight encountered a little bit but not to the magnitude that you had.

About a 1/2 mile from the threshold, a 15 second drop would put you on the ground with about 5 or 10 seconds to spare.

Nothing against the OP, but as with most all passenger accounts, it was not quite as severe as described. With modern day EGPWS systems, the way the OP describes the windshear would close the airport. No doubt it was a fun ride, though.

Sounds scary. I was in a similar situation when flying into BWI last year and thought I was a goner. It may not be 15 seconds, but it sure feels like it!

The only time I had this happen to me was at ORD! We were at final approach, got directly over the runway and had to abort due to wind shear, plane tipped to the left, the people on DEF got a really good view of the runway up close. Scary but probably not as unsafe as it felt. Pilot aborted for comfort of passengers, said he could have landed but it would have been really rough.

Yes. On LH from FRA - DEN in April and we had missed approach due to wind shear. Wheels almost on the ground when we did ours......didn't enjoy it either. Apparantly that day several planes had to divert to C Springs.

It's a common occurrence for my DEN usage in the summer. There's a thread over in Travel Buzz about airports that frequently suffer from turbulence and I nominated DEN based on this.

20 years in Denver and I have never experienced a significant wind shear event. I've had exactly one go-round and that was at Stapleton around 1992 (that one was because the previous aircraft hadn't cleared the runway in time).

Am I lucky? We do have tornadoes every day, you know. :D :D :D

In the evening of 7/10, after circling over Wyoming for a while as a t-storm cleared DIA, I noticed a mainline UA flight landing about the same time we did (probably around 8:30PM). On approach, that plane I saw appeared to be flying a sine wave, gaining and losing elevation throughout its approach. Our pilot was not out for me to ask as I deplaned, so I don't know what was up with that.

In Denver, it is quite common to have some type of windshear occur anytime it is windy. Most often it is of the minor variety. IIRC, Stapleton was one of the first airports that had the Low Level Windsheer Alert System (LLWAS) installed.

Coincidentally, the National Center for Atmospheric Research in Boulder, developed LLWAS.

In Denver, for example, when the LLWAS has detected windshear, the automated weather has a note that says, "Windshear Advisories In Effect", and ATC advises pilots when they are landing of any reported windshear for their runway. Pilots simply take this into account and land as if they are landing in gusty conditions, which it usually is, and add a buffer to their approach speed. This usually just makes for a slightly rougher ride on final and due to the normally mild nature of the shear, it really isn't something those of you listening to Channel 9 should be concerned too about.

As with any landing, if the approach becomes "unstable," meaning the speed or descent rate is outside a certain range, or if the EGPWS starts detecting windshear, the landing will be aborted.

If the windshear is measured above a certain threshold (IIRC, +/-25 knots or greater), the system identifies it as a microburst. When microbursts are being detected, the airport is pretty much shut down because no airliner will land. This is when you see ground stops and airborne holding.

Checko

There are a few possibilities here:

One, it could have been gusty winds affecting the other aircraft's flight path. However, since you did not say your ride was the same and you could make out the sine wave of the other aircraft, leads me to believe this is probably not what was occurring.

The more likely possibility is that your aircraft was flying the electronic glideslope on autopilot, thus your relatively smoother decent. The other aircraft may have been hand flown and had a comparatively less smooth descent because the pilot was making corrections to stay on either the visual or electronic glideslopes.

Another possibility is the other aircraft's autopilot was simply having a tough time capturing the signal, which very occasionally happens.

Checko

That certainly is a scary thought, especially during a landing.