Controlled Flight Into A Thunderstorm (2009)

[Scott Olson]

As many chasers are aware of the power of thunderstorms and respect the power and unpredictability of these storms, so too are many pilots. Flights through severe thunderstorms do occur many times each year, occasionally with disasterous results.

2009 Summary:

1. Air France Flight 447-

One of the most tragic events in recent memory, MAY have involved weather, though the secrets to this mystery remain deep in the atlantic.

Air France Flight 447 was a scheduled commercial flight from Rio de Janeiro, Brazil, to Paris, France, that crashed into the Atlantic Ocean on 1 June 2009, killing all 216 passengers and 12 crew members.[2]
The aircraft, an Air France Airbus A330-200 registered as F-GZCP, took off on 31 May 2009 at 19:03 local time (22:03 UTC). The last contact from the crew was a routine message to Brazilian air traffic controllers at 01:33 UTC, as the aircraft approached the edge of Brazilian radar surveillance over the Atlantic Ocean, en-route to Senegalese-controlled airspace off the coast of West Africa. Forty minutes later, a four-minute-long series of automatic radio messages was received from the plane, indicating numerous problems and warnings. The exact meanings of these messages are still under investigation, but the aircraft is believed to have been lost shortly after it sent the automated messages.[3]

Our own Tim Vasquez has a top-notch analysis of the weather conditions avaliable at: http://www.weathergraphics.com/tim/af447/

2. Lebannon Crash -

Flight took off and pilot failed to make necessary turn to avoid severe storms, then made abrupt turn and crashed. Remains mystery.

All 90 people on board were feared dead after the plane bound for Addis Ababa went down in flames minutes after takeoff at around 2:30 a.m. Monday.Transportation Minister Ghazi Aridi said the pilot initially followed the tower's guidance, but then abruptly changed course and went in the opposite direction. "They asked him to correct his path but he did a very fast and strange turn before disappearing completely from the radar," Aridi told The Associated Press.

3. Corpus Christi - B100 Multi-engine turboprop

On October 26, 2009, approximately 1142 central daylight time, a Beech B100 King Air, impacted terrain after encountering severe weather near Benavides, Texas.The pilot was aware of a severe squall line near his position and coordinated with Houston Control to get his way through. However, once in the squall line he was called by Houston to verify his altitude. He was originally assigned 25,000 feet. The pilot reported that he was in some pretty strong turbulence and had lost a 1,000 feet of altitude. The controller instructed him to climb.

At 1142:07, an expletive and propeller noise were heard on the same frequency being used by the pilot, and for the next 35 seconds there was sound similar to that made by a stuck microphone.

The aircraft then disappeared off radar. 4 people perished in the crash.



The red dot is the location where the aircraft crashed. Echo tops were noted between 25,000 and 40,000 ft.
Note the well defined gust front. The aircraft was generally above most of the significant precipitation echoes but clearly was experiencing severe turbulence.


Top 5 Weather Events from the cockpit for 2009: (From ASRS)

1. Let's get outta here:

I was pilot flying. Was aware of weather both at the time of departure, and during entire phase of flight. Had a departure maintenance delay due to inoperative CTR fuel pump. Took an hour to fix. Got routine updates in flight from Dispatcher who did an outstanding job of keeping us informed, both of the weather and PIREP of other aircraft who landed ahead of us. Had to do some minor deviations for weather on arrival. Nothing more than light to moderate precipitation on weather radar. Descended to 2900 FT MSL, per approach plate to pick up glideslope. At FAF inbound, Approach Controller advised of windshear alert. Captain and I discussed situation, light to moderate turbulence and precipitation on approach. Decided to continue approach, but reviewed windshear escape procedures as well as a departure plan due to rising terrain at departure end of runway at approximately 2500 FT MSL on glideslope with autopilot and autothrottle engaged, aircraft began to bank 25 degrees to left. Captain asked if I was doing that at the same time I disengaged autopilot. He, Captain said, "Let's get outta here" I performed the normal go around procedure and called for flaps 20, gear up set and armed Missed Approach Altitude. At that point, we encountered the worst windshear and severe turbulence I've ever seen in my flying career since I started flying at age 13. Hard time focusing on instruments, airspeed decaying 30-40 KTS in a matter of seconds, both Captain and I pushing on yoke trying to build airspeed. When we flew through the tailwind portion of microburst and into the headwind portion, the airspeed began to build rapidly. We began with a normal go around, but turned into a windshear microburst procedure. Flaps were left at 15 degrees, and airspeed increase to 250+ KTS. We exceeded the flap limitations during a Microburst/Go Around/Severe Turbulence Escape procedure. At approximately, 1500 FT MSL, aircraft flew past microburst, we cleaned up the aircraft, and aircraft began to accelerate normally. ATC asked our intentions. I told the Captain in no way did I want to return to the severe weather. He absolutely agreed and decided on our published alternate. I felt it was a great idea. Approach and landing at our alternate was uneventful. Advised Dispatch in flight after incident that we were diverting to our departure airport. Upon landing, called Maintenance for flap limitations exceeded during windshear/severe turbulence go around.

2. 90 Degree Bank Angle:

During the cruise flight at 12,000 FT on IFR flight plan in IMC, I experienced turbulence in a build up that caused loss of aircraft control. As I recall the timing of events, I was under Cleveland Center control at the time and was on an approximate 290 degree heading and deviating around obvious thunderstorm cells easily viewed on NEXRAD some 20 nautical miles northwest of Toledo, Ohio. In less than a second I found the aircraft in a 90-degree bank and descending over 1000 FT per minute. This event was accompanied by unexpected heavy rain. After leveling the wings I found myself on an approximate 90-degree heading, and at 11,200 FT altitude. Once stabilized on this heading and regaining the assigned 12,000 FT altitude I asked for the re-route to gain time to assess weather and the best course of action. I was handed off to Detroit Approach Control and they assigned 10,000 FT altitude and granted request to direct Ann Arbor and then direct destination. At the time of the event I was navigating in part on NEXRAD images on my moving map to avoid as much precipitation as possible, At the time of the event I was clear of all precipitation on the moving map over ten miles in any direction. There were isolated thunderstorms across a wide area of Michigan and Ohio. At this time and it appears in my judgment that I likely entered a building cell that was not referenced on NEXRAD image less than 5 minutes old. Crossing this frontal boundary again, I would request even more significant deviations and remain at an altitude that allowed visual conditions as much as practical. As additional follow up, I train yearly with type-specific instructor and I believe this instruction allowed me to regain control of the aircraft and assess the aircraft loss of control as expeditiously as possible. I also want to thank ATC for providing efficient help in re-routing in what was a busy day near DTW airspace. This flight concluded with further deviations throughout the flight. As I flew past Green Bay, build-ups began in earnest again and I climbed to 16,000 FT to maintain visual separation from clouds. Again with significant deviations from 'direct' flight plan, I was able to maintain clearance from thunderstorms obvious through the aircraft windscreen and on NEXRAD. Although canceling the flight with Minneapolis Center while still airborne the Controller did not receive cancellation and a phone call was required to close out flight plan.

3. Flying over severe storms:

On the day of the flight, we observed two large thunderstorms over the midwest. The flight plan had us going through the weather. The Captain and I discussed the best way to circumnavigate these two cells. We did not agree. The captain wanted to climb and try to top and go between the two cells. The distance between the two cells was approx 15 to 20 miles. I wanted to turn to the north and go around the cells avoiding them completely. This discussion lasted several minutes. Against my requests we climbed to FL380. The two cells were painting level 4 and 5 on the radar and tops to FL420 according to ATC. The wind was out of the northwest approximately 90K and the anvils of both could clearly be seen. The anvil of the first cell had blended into the second cell. Once we climbed to FL380, it was clear that we could not top the weather. I again asked the Captain if he wanted to deviate. He did not. I turned on the seatbelt sign and asked the flight attendants to be seated, they complied. Approximately 3 to 4 minutes after penetrating the anvil, we experienced severe turbulence. The aircraft oversped by approximately 5 to 15 KTS, which disengaged the autopilot. The aircraft abruptly climbed 800 to 1200 FT. I immediately requested FL340 from ATC and was granted this. During this event, I asked the Captain if he still felt as though he made the right decision. He agreed that we should have turned north to go around the weather. We were IMC for approximately 15 to 20 minutes with light to moderate turbulence the entire time. After we had passed through the weather the flight proceeded normally and as filed. We continued to circumnavigate around weather with us agreeing on the correct avoidance headings. The Captain's trip ended in ZZZ. The flight attendants and I went on to our next destination. I had asked the flight attendants about the event. They told me they were very concerned and that some of the passengers had screamed and were holding on to each other. They said that there were no injuries reported. The Captain's decision to attempt to top and go between the cells, I feel, was the wrong one. He later agreed stating that it didn't look that bad on radar. I also should have been more clear in my repeated requests to go around the weather. I will do this in future flights.

4. Encountering downdraft over top of severe storm.

We were in cruise flight and thought we were traveling over the very top of severe weather. The ground based doppler showed we were entering a band of narrow storms however the onboard radar showed the storms below our path. The aircraft began to vibrate (pre-stall) and we noticed the angle of attack indicator showing we were about to stall. We asked the Controller for lower and he cleared us to 36000. There was visible lightning and light hail in our IMC conditions. The aircraft descended under our control and was stabilized at 36000 when we entered VMC and climbed back to our normal cruise. We think that we entered an area of downdraft and the autopilot trimmed the nose up to the point of pre-stall. We never noticed the autopilot trimming action. As a result we are going to adjust the audio trim movement indication so it can be heard.

5. Lightning strike:

At FL380, aircraft was struck by lightning, right forward window shattered but pressure was constant. Declared emergency and descended to land.

It's been a bit slow around here and thought I would add something to the mix. Weather is directly and indirectly releated to a large percantage of airline crashes. Some of these remain a mystery. NASA ASRS reports feature all sorts of interesting phenonema encountered by aircraft. There are likely many more that deserve to be mentioned, if you have one you want to add please feel free and add it.

-Scott Olson

 

[Mark Blue]

Very interesting post Scott. It would be neat if we could see the air parcels in some of these situations and/or scenarios, so we could better understand what the atmosphere is doing during these events. If only the air wasn't invisible...

 

[Warren Faidley]

Nice report... As a storm chaser and pilot it is always interesting and sometimes disturbing to be a passenger in a commercial flight encountering bad weather.

I recall a PM flight from St. Louis to Tucson about 7-8 years ago after I conducted a speaking engagement. Just before take off, I noticed an obvious supercell structure about 5-10 miles south of the airport illuminated by almost constant lightning. After takeoff, the pilot continued in the direction of the storm as I watched out the window, waiting for him to bank right. For some odd reason, he turned too late and we flew right through the edge of a massive towering CU, likely the tallest part of the flanking line. The turbulence was so bad people began to pray out loud. I was more irritated, knowing we were likely safe. (While trying to stay steady to get a shot of lightning hitting the wing). The plane was struck by lightning multiple times, again, not a real hazard, but the people were freaking out.

W.

 

[Olivier Staiger]

in June 2003 , one morning (!) I saw a storm on radar that looked hook-ish, in the Jura hills near Geneva.

later I learned that an Easyjet airplane had taken off from Geneva and had tried to fly through the storm , or too close for comfort.... and encountered damaging hail, they had to do an emergency landing back in Geneva..

I had seen that hook echo storm and thought, how silly ...


images are impressive.

http://www.tuxboard.com/?images-l-a...ance-de-geneve-est-entre-dans-un-mur-de-grele

http://avion-radiocommande.over-blog.com/article-36981273.html

 

[Scott Olson]

Wow, looks like it took quite the beating! The nose looks significantly dented in, could have very well damaged the expensive avionics. Open skin on the horizontal stabilizer, ouch. They are LUCKY they didn't go the route of the Southern Airways aircraft that lost both engines due to baseball sized hail and crashed landed on a small highway.

http://en.wikipedia.org/wiki/Southern_Airways_Flight_242

in June 2003 , one morning (!) I saw a storm on radar that looked hook-ish, in the Jura hills near Geneva.

later I learned that an Easyjet airplane had taken off from Geneva and had tried to fly through the storm , or too close for comfort.... and encountered damaging hail, they had to do an emergency landing back in Geneva..

I had seen that hook echo storm and thought, how silly ...


images are impressive.

http://www.tuxboard.com/?images-l-a...ance-de-geneve-est-entre-dans-un-mur-de-grele

http://avion-radiocommande.over-blog.com/article-36981273.html

 

[Mike Smith]

I did some work on Southern 242 (including a submission to the NTSB). The pilots were apparently using "iso-echo contour" (where the most intense part of the storm is made to appear black surrounded by white echo of lesser intensity). Unfortunately, they shortened the range of their radar (zoomed in) to such an extent that the black appeared to be "no echo" on their scope. They "cut across" that area (their words per the cockpit voice recorder) and immediately ran into heavy rain and large hail.

This exact problem would not occur today because all or virtually all onboard radars are color. That said, attenuation of 3cm aircraft radars is a real problem and does, at times, mislead pilots.

 

[Scott Olson]

I did some work on Southern 242 (including a submission to the NTSB). The pilots were apparently using "iso-echo contour" (where the most intense part of the storm is made to appear black surrounded by white echo of lesser intensity). Unfortunately, they shortened the range of their radar (zoomed in) to such an extent that the black appeared to be "no echo" on their scope. They "cut across" that area (their words per the cockpit voice recorder) and immediately ran into heavy rain and large hail.

This exact problem would not occur today because all or virtually all onboard radars are color. That said, attenuation of 3cm aircraft radars is a real problem and does, at times, mislead pilots.

Very interesting Mike! I suppose that explains the pilots identifying 'a blowing alley effect' or 'opening' of the storm that they thought would allow them to traverse for a safe landing.

 

[Mark Blue]

After reading Warren's post it reminded me of a flight my wife and I took in the mid 90s on our way to Florida. We had a connecting flight on Delta, so our first leg took us to Houston. At the time a winter storm was moving in from the west and as we left Stapleton airport in Denver, the upper level low was in a position that would mean surface cyclogenesis would occur in SE Colorado at about the time we were flying in that direction and/or vicinity. I could see from the window that we were flying SSE and I mentioned to my wife that I felt as though we were in for a huge surprise and couldn't believe that the pilot was heading right towards the bullseye. Probably 35 or 40 minutes into the flight we hit turbulence like one can only imagine. The flight attendants were lifted off of the floor and the pilot asked them to stow everything and buckle in for the ride. That was the worst "white knuckle" express of a ride I have ever been on. To this day whenever we fly I always get nervous when I feel any kind of turbulence.

When I was about 7 years old my dad had his pilot's license and he decided to take the family on a vacation to the Black Hills. We lived in Central Nebraska at the time and we flew there in a small Cessna, like a 152 or whatever their smallest plane is. When we were over the Badlands of SD we hit some thermals that took us on the most invigorating roller coaster ride of our life. My dad said we were losing 1500 feet of altitude at a time in a matter of seconds, then just a short time after that we would get lifted up the same distance in the same manner. It's the feeling where your stomach is in your throat like when you go through a country intersection in a car, but only magnified by about 20 times. Flying is definitely not my favorite past time as I have had one too many scary events to be fond of it.

 

[Skip Talbot]

Wow, good stories and info by all. I just got my private pilot's certificate a couple weeks ago, and have often thought about what would be involved chasing storms from the air rather than the ground. I've seen videos of it done effectively, but these stories really highlight how extremely dangerous it is to fly near thunderstorms. In most of the cases it sounds like bad judgement and lack of situational awareness. Why fly into a storm when you have so many opportunities, before and during the flight, to avoid doing so?

There is a great video production that has a lot of information on flying in storms and aerial storm chasing. The shots of supercells and convection from the air featured in the video are exquisite. I highly recommend anyone who hasn't seen it to check it out: http://www.convectionconnection.net/

 

[MClarkson]

Unless you want the US air traffic system to essentially be paralyzed every other day in the summer, you have to accept the fact that planes are going to fly near or through thunderstorms with some regularity. Especially at high altitude, where thunderstorms are "generally softer" and the ground is much further away. Air France got unlucky doing what lots of other planes do all the time. Those pilots also may not have correctly chosen a weaker spot in the line, or reacted improperly to turbulence, but its hard to say for sure since the exact manner in which the thunderstorm won is not yet known.

And airborne weather radar does give pilots a couple different ways to screw up. You have to do some stuff manually that is already done for you in a nexrad image, not to mention they attenuate faster and the resolution is lower.

 

[Dave Marshall]

I was (and am about to be again) an aviator in the USAF. There were a number of times where mission requirements didn't permit us to go around thunderstorms, though we only really core punched a couple of smaller storms. We were also capable of climbing high enough to get over most storms. Some aircraft aren't that lucky.

Iraq sees some real ass kickers in the spring, and it was pretty unnerving to watch a really rocking electrical storm from a distance knowing eventually you're going to be flying in/around it.

There is a youtube video of a KC-135 that has always set my hair on end watching it.
http://www.youtube.com/watch?v=4sA-Hk_jnPg

Not a fun way to chase....

 

[Jay Bell]

Hi Dave!

Great video! Unfortunately, spending years as an airline pilot, I can totally relate to it. More times than not, you can go around, but there are those times, that you just don't have any really good options. Punching through even a small cell can rattle your world. The other part that stinks is, once you are in that kind of weather, the static buildup on the aircraft is so high, that most times you can't communicate with ATC (at least in civilian planes). Either they can't hear you or you can't hear them. Even after years of doing it, I still get a knot in my stomach every time I see that I'm gonna have to deal with that kind of weather! Thanks for your service and thanks for the post!

Jay Bell