Scott Olson
EF5
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.
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.
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.
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:
2. 90 Degree Bank Angle:
3. Flying over severe storms:
4. Encountering downdraft over top of severe storm.
5. Lightning strike:
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
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
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