It’s time for another edition of Ask Cranky and today, it provides a good excuse to write more about Boeing’s 737 MAX problems. No small talk needed… let’s get into this.
Everyone is bashing Boeing right now, but is there any real difference in the growing pains of the 737 Max vs the computer glitches that caused the pitch down incidents on the Quantas [sic] A330s?
-David
I love a question that makes me do research. I vaguely remembered a Qantas incident on an A330, but I didn’t recall it being all that similar. It turns out, it was more similar than I thought.
Of course, the problem on the 737 MAX is unique. The MCAS automatically pushes the nose down on the airplane when the angle of attack is too high, and no other airplane has an MCAS. Why not? Well, the 737 has been stretched and updated so many times that it’s like a Barbie doll. It can’t stand on its own. The MCAS keeps it flying straight. The A330 has no such issue, but that doesn’t mean there couldn’t have been an example of an airplane forcing its own nose down for other reasons. That happened to a Qantas aircraft back in 2008.
The A330 That Forced Its Own Nose Down
Qantas flight 72 was operated by an A330-300. It left Singapore on October 7, 2008 on a flight to Perth. This airplane had no problem on takeoff as the MAX aircraft did. Instead, it was cruising along at 37,000 feet near the coast of Western Australia when things started to go wrong.
The A330 has three air data inertial reference units (ADIRUs). Just what is an ADIRU? I’ll gladly let Wikipedia explain.
An air data inertial reference unit (ADIRU) is a key component of the integrated air data inertial reference system (ADIRS), which supplies air data (airspeed, angle of attack and altitude) and inertial reference (position and attitude) information to the pilots’ electronic flight instrument system displays as well as other systems on the aircraft such as the engines, autopilot, aircraft flight control system and landing gear systems.
Got that? They basically provide all the most important flight data to the computers onboard so they can make the right decisions. So, yeah, it’s pretty important to have them functioning. On this particular flight, one of the three ADIRUs malfunctioned and started spewing spikes of bad data. Even though the other two ADIRUs were working just fine, this data caused the airplane to become confused. A number of error alerts sounded, the autopilot disconnected, and the pilots took over manual control. Soon after, the airplane’s systems pointed the nose down.
This was no gentle descent. The airplane reached over an 8 degree pitch angle quite rapidly and people were thrown about the cabin. There were more than 100 injuries with 12 being serious. (And yes, the majority of those fools weren’t wearing seatbelts.)
The pilots tried to counteract the airplane, but for 2 seconds, they could not. Then the airplane responded and they went back to normal flight. Two minutes later, however, a less severe pitch down command came in. They recovered once again and diverted immediately. The airplane landed without further incident.
Comparing the A330 and the 737 MAX Incidents
So, here we have an airplane that tried to push its own nose down multiple times after seeing bad data indicating that the angle of attack was too high. Does this not sound a whole lot like the 737 MAX problem that we’re dealing with today? It does, but obviously the outcomes were different. The A330 was never grounded, and as far as I know, there wasn’t a huge negative public reaction to the airplane. What was different?
Let’s start with the obvious. Qantas 72 landed safely and nobody died. Regulatory agencies have an unfortunate habit of being reactive, but if nobody dies, there’s a whole lot less pressure to react at all. But there was much more to it than that.
Unlike the 737 MAX, the A330 family was far from being a brand new airplane. The first A330 was delivered more than 15 year before this incident. In the 28 million plus flight hours between then and 2008, nothing along the same lines had ever happened.
Sure, in 2006, this same exact airplane had a similar ADIRU fault problem off the coast of Western Australia. But in that case, the airplane didn’t adjust flight controls at all, so it was a non-event from a passenger perspective. Another Qantas A330 off Western Australia had a similar issue at the end of 2008 (what the heck is it with Western Australia?!) that again resulted in no change to flight controls.
Even if those had resulted in a nose-down situation, it wouldn’t have been nearly as dire as in the case of the MAX. All of these happened at cruise altitude where it’s a whole lot easier to recover from any upset. Altitude is your friend.
Lastly, this wasn’t some newfangled system on the A330 that pilots weren’t even told about. This was just a malfunction of systems that the pilots were familiar with. The pilots had been trained on how to handle these situations, and in the case of Qantas 72, they did.
You might be wondering, “uh, what about Air France 447 in 2009?” That is the only A330 accident with a major loss of life (except for Afriqiyah Airways putting an airplane into the ground in Libya a year later), and it did involve instrument issues. But that was very different.
That flight from Brazil to Paris crashed into the Atlantic Ocean. This wasn’t a case of faulty data due to computer issues. This was a case of faulty data due to frozen pitot tubes. That still shouldn’t have brought the airplane down, however. The pilots just failed to fly the airplane.
Why the MAX Was Grounded and the A330 Was Not
Unlike the A330, the 737 MAX is a brand new airplane, and it went down right on takeoff soon after being introduced into service. We’ve now had two accidents within a few short months, at least one of which is thanks to the new MCAS system which wasn’t properly explained to pilots. There is no history of safe operation of the airplane to help quell fears.
The 737 MAX delivery schedule is far more aggressive than the A330’s ever was. There are a lot of these airplanes going into service every month… at least there were until the airplane was grounded. So why did the MAX get grounded? There’s no doubt some of it is simply a reaction to all the dead bodies. Pardon the bluntness, but it’s the unfortunate way things work.
But looking at the way this airplane was designed and how training was pushed out, it seems to have been done in a rush and could, to put it mildly, have been thought through better. By grounding the airplanes, the authorities are effectively hitting the pause button to let training and automation catch up to the airplane.
You’re probably wondering what happened in the wake of Qantas 72. Well, first, it was noted that everyone should keep their seatbelts on when seated. That’s obvious.
But the algorithm that told the airplane how to react to the rare “multiple data spike” incident on the aircraft was redesigned to provide more protection. It shouldn’t happen again. Further, there were new training modules and procedures put into place to help make it safer for everyone. I’d recommend a read through the very thorough final report from the Australian Transport Safety Bureau. It’s a good (but LONG) read.
The odd thing is that I expect the resolution to the 737 MAX issue will be similar. Improve training, make the software safer, and then everyone should be satisfied. That’s not to suggest that what happened to the A330 was the equivalent of what is happening to the MAX. The A330 was a proven, safe airplane for many years before this freak incident occurred. The MAX has a long way to go before it gets to that point.
