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Sailvi767
24th Jul 2019, 23:41
Let’s everyone be careful out there. I have witnessed some strange things in the last month. On the 22nd at JFK with level 5 thunderstorms in the area a KLM flight took off with a 16 knot tailwind on 22R with a huge cell 3 miles N and tower calling a wind shear alert. After a runway switch to 4 a Aero Mexico flight accepted a take off clearance with no available departure path and WS alerts and only cancelled take off when they got a onboard WS alert. 2 minutes later a Ethiopian inbound flight landed on 4R after declaring a fuel emergency. As they touched down we were getting onboard radar windshear alerts for the arrival corridor. The cell over JFK had tops reported at 56,000 feet at that time.

Dan_Brown
25th Jul 2019, 00:47
Nothing wrong being reminded of the dangers of extreme WX, for example and the pssible consquences, should things not go according to plan.

We're all fallible, each and every one of us. I have fear of T/S's among other things in aviation. If we don't have fear therefore respect of possible consquences, we're in the wrong business. It's helped keep me alive up until now.

hunterboy
25th Jul 2019, 09:40
I was in JFK a couple of months ago in the queue for a 22 R departure but facing up towards the ILS arrival path during particularly bad weather, causing >1 hour ground and air delays.
We were surprised when our PWS went off as we were in the queue stationary on the taxiway. Suffice to say, the next couple of arrivals on the approach went around.
One of the times we were glad to be on the ground with loads of excess fuel happy to wait it all out.

Sailvi767
25th Jul 2019, 11:17
It was actually the first time I have seen PWS work on the ground and we got multiple alerts on the 22nd. Nice to watch it in action so to speak.

flyboyike
26th Jul 2019, 11:17
I thought Les Abend retired?

Capt Fathom
26th Jul 2019, 11:24
Let’s everyone be careful out there.

Luckily everyone reads PPRuNe! :E

M.Mouse
26th Jul 2019, 13:30
Letís everyone be careful out there.

Is the implication of that statement that normally people aren't careful?

Sailvi767
26th Jul 2019, 19:41
Is the implication of that statement that normally people aren't careful?

I would say sometimes people are less than careful depending on circumstances. KLM knew that if they did not depart it was going to be a long night. Tower asked if any of the other aircraft in line were willing to depart as KLM rolled. The radio stayed silent so the majority were careful and yes we all had a long night.

Dan_Brown
26th Jul 2019, 21:35
Certain airlines in a hurry, "gethomeitis"? Commercial pressure raising it's ugly head again?

Sad how history has a habit of repeating itself.

Hotel Tango
26th Jul 2019, 23:10
On the 22nd at JFK with level 5 thunderstorms in the area a KLM flight took off with a 16 knot tailwind on 22R with a huge cell 3 miles N and tower calling a wind shear alert.

Fair enough, but for the sake of impartiality the DAL172 departed 3 to 4 minutes in front of the KLM. The KLM made his left turn slightly earlier than the DAL.

aterpster
27th Jul 2019, 13:42
Fair enough, but for the sake of impartiality the DAL172 departed 3 to 4 minutes in front of the KLM. The KLM made his left turn slightly earlier than the DAL.
Are you agreeing that both of them did risky departures?

Hotel Tango
27th Jul 2019, 14:20
Are you agreeing that both of them did risky departures?

It is not for me to judge either way. I wasn't in their cockpits looking at whatever data they were looking at. I just wanted to put the record straight that, as I felt was being implied, it wasn't just the KLM that opted to depart at that time. If I have a personal opinion, to me it would imply that (with CRM) there were at least 4 professional pilots who considered it safe enough to go and the Delta was not heading home!

Tomaski
27th Jul 2019, 14:35
We were surprised when our PWS went off as we were in the queue stationary on the taxiway.

I've had PWS go off because it was sensing the thrust of an aircraft in front of me (no weather in the area). Probably depends on the radar unit.

the_stranger
27th Jul 2019, 15:20
Certain airlines in a hurry, "gethomeitis"? Commercial pressure raising it's ugly head again?

Sad how history has a habit of repeating itself.
How sad you are jumping to conclusions without being there...

Sailvi767
28th Jul 2019, 12:42
Fair enough, but for the sake of impartiality the DAL172 departed 3 to 4 minutes in front of the KLM. The KLM made his left turn slightly earlier than the DAL.

The above is correct however Delta had a headwind at the time of departure with no tower wind shear alerts. Both aircraft had a clear departure corridor after getting airborne. Winds and conditions were changing by the minute.

alioth
28th Jul 2019, 23:13
Been a bad year for thunderstorms

Sailvi767
29th Jul 2019, 16:58
We have not had a major windshear accident in a long time. It breeds complacency. This cell had the ability to turn that 16 knot tailwind into 50 knots in the blink of a eye. It’s good to be lucky but luck eventually runs out.

Hotel Tango
29th Jul 2019, 17:45
This cell had the ability to turn that 16 knot tailwind into 50 knots in the blink of a eye.

Just as the minimum headwind component for the Delta when given take-off clearance could have similarly turned into a 16 knot tailwind as it accelerated down the runway and a 50 knot tailwind as it rotated.

It’s good to be lucky but luck eventually runs out.

Well yes, but were they "lucky"? That's quite a damning statement aimed at four fellow professionals.

You've had your say and made your point. It may be valid and it may not. You were not sitting in either of those cockpits.

The Range
29th Jul 2019, 18:58
These guys weren't that lucky.
​​​​​​Accident: Pan American Airways 759 (http://code7700.com/accident_pan_am_759.htm)

Hotel Tango
29th Jul 2019, 19:22
That was 37 years ago on July 9th, 1982. Much has evolved since then!

Dan_Brown
29th Jul 2019, 23:37
Let us not forget the L1011 tradgety at Dallas/Fortworth .

No two Thunder cells the same. Do not, i repeat do not underestimate the power within and in the proximity.

Better and more experienced pilots than most of us have been caught out. As the OP quite rightly suggests, why run the risk? Think of your passengers and crew, as we owe them that much at least.

We humans may think we have aviation "kicked to death". But we haven't and we never will

kibz2005
30th Jul 2019, 03:29
I've had PWS go off because it was sensing the thrust of an aircraft in front of me (no weather in the area). Probably depends on the radar unit.

Please correct me if I'm wrong, but I thought PWS works on the principle of measuring velocity of droplets, not changes in airflow?

Starbear
30th Jul 2019, 04:56
Please correct me if I'm wrong, but I thought PWS works on the principle of measuring velocity of droplets, not changes in airflow?

It does but is also known to be imperfect and why it may be permissible for a crew to disregard it in certain circumstances.

Starbear
30th Jul 2019, 06:03
From a well known manufacturer's FCOM:
The “W/S AHEAD” message is displayed on each PFD. The color of the message depends on the severity and location of the windshear.

Note:When a predictive windshear alert (“WINDSHEAR AHEAD” or “GO AROUND WINDSHEAR AHEAD”) is triggered, the flight crew must carefully check that there is no hazard. If this is the case, the flight crew can disregard the alert, as long as both of the following apply:
‐ There are no other signs of possible windshear conditions
‐ The reactive windshear system is operational.

Known cases of spurious predictive windshear alerts were reported at some airports, either during takeoff or landing, due to the specific obstacle environment.

However, always rely on any reactive windshear (“WINDSHEAR”).

Capn Bloggs
30th Jul 2019, 06:11
Known cases of spurious predictive windshear alerts were reported at some airports, either during takeoff or landing, due to the specific obstacle environment.
A rogue airport in my network produced occasional "GA WS Ahead" callouts in gin clear weather and not a hill in sight. Gets your attention at 300ft on Final!

Hotel Tango
30th Jul 2019, 08:39
Why are you guys citing accidents from way back when WS was not so easily detected nor trained for?

The Delta accident was in 1979 (and on landing).

There were several contributing factors such as the lack of adequate equipment on the airport and on board the aircraft to detect the possibility of WS. The NTSB also determined that a lack of specific training, policies, and procedures for avoiding and escaping low-altitude wind shear was a contributing factor.

The point I'm making is that a great deal has evolved since then. For that reason I remain unconvinced that neither Delta nor KLM took any "risks".

The Range
30th Jul 2019, 08:47
HT, you're correct, a great deal has evolved since then. But TS's are the same, and a strong microburst can still put an airliner down.

Hotel Tango
30th Jul 2019, 09:24
TR, I don't disbelieve that for a moment. Not at all. I also don't for a moment believe that the Delta and KLM crews took any unnecessary risks at the exact time they departed. It's pure supposition by the OP. Finally, if the OP just wished to make a general point, why name one operator? Agenda?

Yaw String
30th Jul 2019, 13:12
Discussing this few days ago.The imaginative mind can see problems that do not exist,but on the converse,a lack of imagination in our industry can bring on its own problems..

Jim_A puts it well,in the following post!

Jim_A
30th Jul 2019, 18:30
One of the inherent problems with this type of scenario is that it probably happens more often than we would like to admit, and having no unpleasant consequence the crews learn the wrong lesson. The phrase "normalization of deviance" comes to mind. Then something bad happens and everyone starts taking the radar returns serious again.

The Range
15th Aug 2019, 13:09
These things can still happen. Thankfully this time nothing serious happened.

​​​​​​https://www.pprune.org/rumours-news/624630-respect-convective-weather.html