In August I wrote about the crash of Voepass flight 2283 which was captured in a flat spin moments before impacting the ground killing everyone onboard. The imagery was shocking and it’s the only time I’m aware of that an airliner has ended up in a flat spin which was likely unrecoverable.
Analysis: Pilot Error At The Heart Of Voepass ATR-72 Crash
CENIPA, the Brazilian accident investigation authority, recently released its preliminary report. This was far more comprehensive in terms of data than what we would normally get from the US National Transportation Safety Board (NTSB) at this stage of an investigation including a detailed timeline and FDR data. That report gives us a very detailed insight into what went wrong on this flight and how this tragic accident happened. The answers are frankly disturbing and difficult to understand. Because the picture painted is one of a flight deck crew that does almost nothing right, failing at even basic tasks. Sadly, like all accidents it wasn’t one thing but rather a cascade of issues that led to the crash.
The picture painted is one of a flight deck crew that does almost nothing right, failing at even basic tasks.
In writing this I’ve relied not only on the preliminary report but also on a video from the Fly with Magnar YouTube channel as he is a current ATR-72 Pilot and check airman. I’m going to try and distill the information down into a summary of what went wrong. If you want a more detailed look I suggest reading the report and or watching Magnar’s video.
With flight 2283 the first threat they encountered was the weather. Flying at 17,000 feet they were right in the middle of an area of forecast severe icing conditions. While airliners are designed to fly in icing conditions, severe icing by definition is a rate of accumulation so high the aircraft systems can no longer keep up. This is an emergency situation that requires immediate corrective action.
Now, just because severe icing is forecast doesn’t mean its present. So, the crew’s decision to fly through this area isn’t an inherently bad one but it does require vigilance. It would turn out the weather was perfect for the formation of supercooled large droplet (SLD) icing. This particular form of icing is by far the most dangerous and severe because you get large drops of supercooled water that when they hit the airplane create a rapid buildup of ice.
The ATR-72 is equipped with a very comprehensive suite of protection features against airframe icing. It has two ice detection systems one visual and one electronic. The visual one is a miniature wing outside the cockpit on the Captain’s side. Procedure states that airframe ice must be assumed to be present as long as there is any ice at all on that probe.
The second is an electronic ice detector that uses a vibrating probe to detect ice and will activate an alarm in the cockpit when ice is detected. The ATR also features electric heating for the propellors, control surface horns, and the cockpit side windows that must be selected on whenever in icing conditions. This is a TAT (total air temperature, the air temp the airframe actually feels as opposed to the actual air temp) of less than 7C with visible moisture in the air. Selecting horn anti icing on also results in the flight computer reducing the angle of attack at which the stall warning system activates.
The final level of ice protection is the de-icing system which consists of boots on the wings, horizontal stabilizer, and the engine air intakes. This system should be selected on and remain on anytime ice is detected on either of the two probes until the visual detector is clear of all ice.
Minimum Speed During Ice
Pilots must also compute a minimum speed to fly in icing conditions based on aircraft weight. On the day in question this was 169 knots. Speed must always be maintained at no less that that speed plus 10 knots which meant a minimum of 179 knots. The ATR is also equipped with APM or Aircraft Performance Monitoring. The First Officer sets the takeoff weight of the aircraft and then the APM system looks at various factors to compare actual aircraft performance to predicted aircraft performance. If ice buildup on the airplane is causing increased drag and reducing the aircrafts performance the APM system has three levels of warning to advise the pilots of this.
First when cruise speed is 10 knots below the computed value it will activate a CRUISE SPEED LOW message to warn the pilots. This is a reminder to monitor ice accretion and airspeed. When cruise speed drops by more than 15 knots a DEGRADED PERFORMANCE message is triggered. This is an indication of severe icing and airspeed must be immediately increased to the icing minimum plus 30 knots. As this is an indication of severe icing you are now in an emergency situation and the crew should immediately declare an emergency and commence a descent to exit the icing conditions.
Remember severe icing means the rate of accumulation is so high that the aircraft systems can no longer manage it. The final APM warning comes once speed is less than the icing speed plus 10 knots which should never be allowed to happen. The warning INCREASE SPEED should never come on and is the final warning that the aircraft is in danger and immediate action to increase speed must be taken.
The Timeline Of Events
Now let’s look at the timeline of the critical events in the flight from the preliminary report. I’m going to shorten this from what’s in the report for brevity:
- 15:12:40 – the PROPELLER ANTI-ICING 1 and 2 were turned on
- 15:14:56 – the Electronic Ice Detector connected to the Centralized Crew Alert System (CCAS) emitted an alert signal upon passing FL130
- 15:15:03 – the AIRFRAME DE-ICING was turned on;
- 15:15:42 – a single chime was heard in the cockpit. Subsequently, the crew commented on the occurrence of an AIRFRAME DE-ICING Fault
- 15:15:49 – the AIRFRAME DE-ICING was turned off
- 15:16:25 – 16:12:55 the Electronic Ice Detector goes on and off multiple times staying on from 16:17:32 to the end of the flight
- 16:17:41 – the AIRFRAME DE-ICING was turned on; We don’t know if it was working or not.
- 16:18:41 – at a speed of 191 kt., the CRUISE SPEED LOW alert was triggered.
- 16:18:55 – a single chime was heard in the cockpit. At this time, the communication with APP-SP was taking place
- 16:19:07 – the AIRFRAME DE-ICING was turned off
- 16:19:28 – at a speed of 184 kt., the DEGRADED PERFORMANCE alert was triggered, together with a single chime
- 16:20:00 – the Second in Command (SIC) commented, “a lot of icing”
- 16:20:05 – the AIRFRAME DE-ICING was turned on for the third time;
- 16:20:33 – APP-SP cleared the aircraft to fly direct to SANPA position, maintaining FL170, and informed that the descent would be authorized in two minutes
- 16:20:39 – the crew acknowledged the flight instruction received (last communication performed by the flight crew)
- 16:20:50 – the aircraft started a right turn in order to fly to SANPA position.
- 16:20:57 – during the turn, at a speed of 169 kt., the INCREASE SPEED alert was triggered, in conjunction with a single chime. Immediately afterwards, vibration noise was heard in the aircraft, simultaneously with the activation of the stall alert
- 16:21:09 – control of the aircraft was lost, and it entered an abnormal flight attitude until colliding with the ground. The aircraft rolled to the left to a bank-angle of 52 degrees, and then rolled to the right to a bank-angle of 94 degrees, performing a 180-degree turn in a clockwise direction. Subsequently, the turn was reversed to an anticlockwise direction, with the aircraft completing five full rotations in a flat spin before crashing into the ground.
There is a lot there so let me summarize. They were flying in an area of forecast severe icing which should have been known to the crew. The aircraft was doubtless accumulating ice which is very unlikely to have melted off given the conditions they were in. So even if the electronic ice detector wasn’t indicating ice its almost certain the visual one was.
Despite this after getting a fault in the airframe de-icing system the crew took no action to exit the conditions. At 16:18 CRUISE SPEED LOW comes on confirming that the aircraft is carrying ice. The fact that the airframe anti-icing system is switched on at 16:18 and off again after a single chime at 16:19 possibly indicates that it was faulted again. But note the sequence at 16:19. With airframe de-icing off the DEGRADED PERFORMACE alert is triggered and then the First Officer comments on how much ice there was. Airframe de-icing is selected back on at 16:20 but despite the presence of an indication of severe icing and an emergency situation the crew takes no action.
The final minute of the flight is chilling. At 16:20:50 they initiate a turn at 30 degrees angle of bank which unless they descend will increase the AOA putting the aircraft closer to a stall. Then 7 seconds later INCREASE SPEED is triggered along with airframe vibrations (which is the airplane telling you it’s literally about to stall and you need to react NOW) and then the stick shaker triggers. Despite all these events the crew does not apply the stall recovery procedure. They don’t lower the nose, they don’t push the power up, the don’t extend the flaps the only thing they do is increase the propellor RPM to 100%. 12 Seconds later all control of the aircraft is lost and it ultimately enters a flat spin.
A Failure Of Two Pilots
I’m honestly at a loss for words here. Magnar in his video says that its too easy to blame the pilots and he’s right. We don’t know how they were trained or what experience they had beyond the number of hours in a log book and I hope CENIPA will be looking closely at those questions. But at the same time, I’m sorry, this is an utterly colossal failure by the two pilots. Not only do they seem totally unaware of the danger they are in not once do they apply the proper checklist to deal with the lights that are coming on. The QRH or quick reference handbook has a checklist called Procedure for icing conditions which isn’t referenced or followed. DEGRADED PERFORMANCE means you are in severe icing and they failed to apply both of the relevant checklists for that.
There are also procedures specifically for CRUISE SPEED LOW, DEGRADED PERFORMANCE and INCREASE SPEED none of which were followed. They didn’t run the checklist when the airframe icing system faults, they just turned it off and keep flying. When you’re an airline pilot applying the proper checklist when a light comes on is piloting 101. There is simply no excuse for these failures. Not to mention that with the airplane literally shaking and the stick shaker going off they still don’t take proper action which almost certainly would have saved the airplane and prevented the spin.
Furthermore, even a poorly trained a professional pilot has an obligation to understand the sort of events that have killed people in the past. We’ve had more than enough turboprops lost to airframe icing to make it a threat anyone flying one should be thinking about entirely on their own. It goes back to professionalism and airmanship as I’ve talked about in the past.
The sad fact is that 60 people lost their lives because the two pilots they trusted to keep them safe inexcusably failed to do so. The question that has to be answered now to prevent it from happening again is why.
> Read More: Airmanship: What Pilots Need Most
image: CENIPA
Hey , everyone makes mistakes , ( said Einstein ) .
We can only Attempt to mitigate everyone’s mistakes .
And Nothing can overcome gravity or weather , whether a piper cub or a 747 .
This appears to be incompetence most likely coupled with fear on the part of the captain. Even if the de-icing system failed do to the shear amount of ice the captain took no corrective action to get the aircraft out of that situation. Even when the first officer stated that’s a lot of an icing the captain took no corrective action to save the aircraft. The first officer took no corrective action to safe the aircraft where were the CRM skills. When air traffic control tell them to maintain FL170 they would descend them in 2 minutes why didn’t either the first officer or the captain tell ATC unable we’re descending now do to severe icing and probable issues with the aircraft de-icing systems. And finally with the amount of ice they had on the wings why, why, why would you initiate a 30 degree bank angle turn when your speed is at 169 kt and decreasing rapidly.
These are not mistakes, 60 innocent people didn’t die because of mistakes this appears to be incompetence coupled with fear, what action did the captain take at all to save this aircraft? And did the first officer who at least noted the the severe icing not step up and takeover the situation seeing that the captain didn’t respond at all when advised of the severe icing?
@proschwit … +1 . Perhaps “incompetence coupled with fear” on the part of the flight crew can be a result of mistakes in the training and employment departments ? Perhaps all flight crew ought to be re-evaluated periodically ? Perhaps the executive group fell captive to a self-satisfied and self-assured blindness ? Perhaps other pilot’s opinions of each fellow pilot ought to be taken into consideration ?
16:17. We don’t know if airframe deicing was working.
Was this because it was on/off in the previous time period or because ice was now rapidly accumulating?
@Maryland … +1 . Excellent comment .
We don’t know if it was working based on the fact it had faulted previously. Also note that shortly after it terms on we get a single chime and then it’s turned off again. My gut is very strongly telling me that the chime was the system faulting again which is why they turned it off even though they still had ice on the airplane.
Thanks. This was helpful
Excellent details on a tragic situation. The bigger question is when this happens again, which it will, is the next crew ready to deal with it? And what refresher training is in place to ensure they are?
Great analysis of the very tragic event. Not trying to make excuses for the pilots here but the situation they faced (ice formation) might probably be the same as someone living in Texas having to drive in snow one day. It is probably so rare in places like Brazil that even if they were trained, they were probably not ready to act on it since the chances of facing that situation was so remote. Unfortunately, they faced and failed.
At those altitudes during Brazilian winter icing is far more common than you think.
You might be right. I wonder if there is any type of record on how many flights in Brazil had gone through a situation so severe like this that pilots had to follow all the protocols not followed by these pilots.
Even if this was a crew that had never seen airframe ice before that doesn’t change the fact they weren’t running any of the proper checklists at all. And if you’re not used to ice and your aircraft is suddenly loading up with it with a failed de-ice system any reasonable professional pilot would know this was bad. Very bad. These two didn’t seem to have a clue.
It sounds somewhat like American Eagle 4184 – the Roselawn crash, though I don’t think anyone (except the self-interested airplane maker) suggested that the pilots were at all to blame in that incident.
Its actually very different from Roselawn. In that event a ridge of ice was building up behind the boots and when the pilots retracted the flaps to start accelerating out of the hold the increase in AOA caused an aileron hinge moment reversal which the crew was unable to counter. In that case the pilots didn’t do anything wrong and design changes were made to the airplane as a result.
This one is 100% pilot error. The only question left is why they made the errors they did.
I will also say as an aside that I’m very impressed by the comprehensive nature of the ATR’s ice protection system. It well thought out and quite comprehensive and should any crew that follows proper procedure out of trouble.
Very interesting, thanks!
Not sure if you read Admiral Cloudberg but they just did a pretty extensive analysis of the Roselawn incident and talked about aileron hinge moment reversal – very interesting and horrifying but all over my head a bit.
So to break this down the first and practical solution would have been to declare Pan Pan due to the malfunction and descend quickly to a lower and warmer altitude. I mean, how could this have not happened? The only thing imaginable is that the malfunction was so common that they just ignored it as they had in the past and were fine.
I am REALLY fed up with pilot error getting blamed time after time for this airplane’s fatal crashes in icing conditions. Go back to the very first crash of an ATR 42 and what was the reaction of ATR’s MD? “This airplane could be flown by trained monkeys”, the inference being the (Italian) pilots were incompetent.
Once is excusable. Twice may be a coincidence. 3 or more times is a trend. This airplane was designed by engineers who had never designed an anti iced wing used on turboprops rather than the deiced wing used on jets. It’s NOT a turboprop problem as the Dash 8, SAAB 340, Fokker 50, Beech 1900 and Jetstream continue to fly safely in icing. This airplane is dangerous, especially if the pilots’ are not ultra vigilant. I for one go out of my way not to fly it.
@skedguy … +1 . Thank you . Consider the many cautionary warnings about the Osprey .
Sorry, but ice and/or poor plane design is not what killed these people. Accidental entry into a high power/accelerated stall did. That’s pilot error of highest degree. There is nothing more basic you can do to crash a plane other than CFIT.
The fact that icing made a stall more likely is immaterial because if they had followed proper recovery procedures for the situation they were in, they would have eventually removed themselves from the severe icing through the change in altutude. The only thing that mattered is that they had multuple – I repeat MULTIPLE stall warning signs and indiciations over a period of several minites and they ignored ALL of them because they were fixated on the icing situation.
It’s similar to Air France 447 from 15 years ago – everyone was paying so much attention to the weird indications in the cockpit that no one was paying attention to basic airmanship.
The first rule of flying is to fly the plane.
Very thoughtful analysis, thanks @121PILOT. What a waste of life. I hope the airline is held culpable and pays hefty fines and damages to the families of those that perished
A lot of good information, sadly given from a Monday morning quarterback perspective. I assume the author is more in love with clicks than flying. Sad!
What are you, the Brazilian pilot’s mother?