In light of the recent announcements made by Virgin to acquire 4 Max-8s and Max-10s, I had been scheduled to complete the MAX differences training.
Side note: This month is full of checking and training (annual line check, max differences training, and my cyclic - 3 days instead of 2, focusing on a 1-day check and 2 days of training).
Before I go into the training on the MAX I will preface this by saying that I in
no way forgive Boeing or defend them for not putting in these additions to prevent the terrible accidents from occurring. The proper training and information in my opinion was
absolutely needed to be given to pilots, as I have found out. Yes, it is a 737, but it feels like a completely different aircraft in terms of the screens and functionality, so the training is definitely needed!
First up, the most noticeable thing was the engine power! Definitely a lot more thrust and it's absolutely needed for the increase in take-off weight by about 20 tonnes. No breakaway thrust was required to get the aircraft moving from a stopped position. The pitch couple is also much more noticeable, ie, you add thrust, and the nose comes up and vice versa.
Next, everyone's favourite topic...the flight controls. I won't go into too much detail as the additions don't affect normal flight however it really is a nice bit of kit. The one I found really impressive was the emergency descent speedbrakes. The spoilers are now fly by wire. Electrically controlled and hydraulically actuated.
This means that on an emergency descent (depressurisation only) when the flight crew raise the speedbrakes, the control unit raises them further automatically. This increased our descent rate from 3800fpm to a staggering 9300fpm!
Other items include elevator jam landing assist, landing attitude modifiers (more so for the -10), manoeuvre load alleviation, and ground spoiler control modules.
MCAS
I've put this under its own heading because I'm sure it'll bring more questions. The MCAS and speed trim system have been dramatically overhauled (for the better!). There are now a lot more redundancies and limits put into place to reduce the amount of trim activation during a non-normal event.
To put this into practice, we put the aircraft (sim) into a deep stall. Some pilots may remember the old stick pusher system. While it's technically not a stick pusher, at the point where the MCAS activates to bring the nose down, the hydraulic system doubles the pressure to the control column momentarily. I tried hanging on to this for demonstration purposes, and it was really overpowering. In that instant, the aircraft recovers really quickly.
Now after MCAS activates nose-down trim, (it is now not running as quickly or for as long as it used to) the trim is taken off again once the aircraft is unstalled.
Trim Runaway
This was next in the sequence and is now really a non-event. For anyone asking if the control column cut out is there. Boeing has added a retrofit software design that acts as a cut-out (for forward control column inputs only) and a redundancy system on top of that.
I actually tried to let it run a bit however, it was quite easily managed now with the other pilot. The technique I used was to trim nose up (in this case) and when I had the aircraft as close to trim as possible I got him to cut out the main and back up stab trim cut out switches. This allowed me to then manually use the trim wheel for smaller inputs even as I was the pilot flying.
Conditions for MCAS operation now include:
- Autopilot
disengaged. So if the autopilot is engaged, MCAS cuts out. This could create another problem by pilots throwing the aircraft at the autopilot and getting it to fix the problem. Which to activate on the 737 isn't so simple as pushing the button.
- Flaps
UP
- Angle of attack above a certain threshold.
- Up to 0.84 Mach
- Only activated 10 seconds after take-off.
- New flight control computer software that has an angle of attack comparison.
- A maximum command limit meaning it no longer trims full nose down as we saw in both accidents. This allows full elevator authority.
- Only one MCAS activation (nose down trim) per event. So if the aircraft exceeds a high angle of attack MCAS will only activate once, not continuously. If there's another high angle event and the threshold is exceeded, it will activate again. For those inclined by numbers, the maximum amounts are 2.5units of nose-down trim at low Mach and 0.65units at high Mach.
- When activated, the system records a snapshot of the stab trim position, and the nose down limit is established from here. So it won't give a full go of the trim if it is already near the maximum limit.
- Once the angle of attack is reduced below the threshold, the stab trim inputs are reversed.
Finally, there is a flight control computer trim monitor function. This is currently used on the NG model during a dual autopilot landing only, but on the MAX, it is now monitoring during all stages of flight, providing additional protection against a runaway stabiliser caused by erroneous computer commands.
There were also a few system changes with the engines, starting, and fuel system warning lights, the most noticeable would be the APU. It has a similar design to the 787 with a new inlet door.
Again I must reiterate that I in
no way excuse the manufacturer for the massive oversight of the MAX program. Having said that, the right information is now out there (and plenty of it!) for the crew. The simulator training should have been done from the inception of the aircraft into service and is such a valuable tool. I could have read about the changes until I was blue in the face. However, it's not until I see something physically that I can then understand how the whole thing works as opposed to a system in isolation.
Given this training, I am looking forward to flying to MAX8 and the -10 (if it gets certified by DEC 2022) and would gladly put my family on it. I understand not everyone will feel the same, and that's ok, that's the brilliant thing about choice.
Here's to looking up!