1. A single Faulty AOA Vane is not a reason to Ground a Fleet of a plane, Planes have this thing called MEL "Minimum Equipment List" whic specifies what is required on the Absoloute Minimum. Planes can be dispatched with alot of Stuff Inoperative and its still Fine
2. There is no Difference, Both flights had the exact same Fault(AOA Vane showing Indications whic are too High). The difference being 1 Crew managed to Cope with the Fault and the other one failed to follow the Stabilizer Trim Runaway Checklist
3. They all had to atleast be Trained for a Stabilizer Runaway Event whic is more dangerous than MCAS Thinking the planes Stalling
4. Because they've Flushed the Pitot Tubes, did additional Tests and they turned out fine so they cleared it again.
If there is Something wrong you Divert, it doesnt matter if your Passengers are going to be Pissed. Atleast thats the way it is with most Western Airlines (EasyJet,Lufthansa,Ryanair,KLM etc.). No Pilot can get Fired for Pre-Cautiously Diverting.
The Captains ALT and SPD indications weren't working on the Previous flight so they Switched the Captains PFD to source its info from the Right hand Pitot-Static port and they continued the Failure and wrote it up after landing. Oh and you can land a Plane with 2 Things only btw. Pitch+Power, the plane wouldnt have "ended up in aland-based crash" thats completly wrong. The QRH gives you Pitch and Thrust Values for a Given weight whic you can use to land your Plane if you had No Speed and Altittude indication on all 3 Displays.
The "Stick"(btw. it's called a Yoke not a stick, there is no such thing as a Stick in a 737) doesn't bring the plane in a nosedive, the Pilots can ALWAYS counter it. and Yes there are 3 Ways to Counterract it really Simply. 1st way, use your Rocker Switches on the yoke to Trim Nose Up (against the Nose Down input from MCAS) whic will also inhibit any Trim Operation wether that is from MCAS or from the STS(Speed Trim System) for 5 Seconds before they start working again, 2. Way is to use the Stabilizer Cutout Switches witch the Crew on the Previous flight have correctly Done. and the 3. Way whic is also the easist is to Just Grab your Trimwheel. The Trimwheel is Mechanically Connected to the Gearbox of the THS via a Steel Cable. If you hold the Trimwheel with your Hand(Whic doesn't require a Hulk to do) No electrical triminput will be able to Override it. That should also be your First thought if the Trim is doing something its not supposed to and you cant figure it out, just Grab it.
What isn't found in the Manual is the Description of the MCAS System whic was operating. and what the Other Crew found and did was the NNC(Non-normal Checklist) of the QRH(Quick Reference Handbook) was the Stabilizer Trim Runaway Checklist, and EVERY Commercial Plane carries a Flight manual(called FCOM in most cases) And a QRH onboard.
The Issue was written up by the FlightCrew on the Previous flight whic was Unreliable Airspeed and Alttitude. Maintenance have done the AMM Tasks and it was working fine again. However no AOA Fault was Reported hence MX didn't fix it. How should they fix something theyre not aware of? and the plane doesnt "Randomly" dive into the Ground, it happens for a Particular Reason. Stall a 737Max with no assistance from the SMYD,EFS and MCAS and then you'll be glad systems like these Exist.
They Have, they made a Tech Log Entry and MX Looked at it, but no one knew the Problem was with the AOA Vane, everyone suspected a Malfuction with the ADR(Air Data Reference) Systems.
You don't have to Find a Checklist, theres this thing whic we like to call Airmanship. Every Pilot needs to know all Memory Items of the Top off the Head. Unrealiable Airspeed? 4° Nose Up and 74% N1. Trim Runaway? Grasp and Hold the TrimWheel. Aeroperu 603? 2 Completly diffrent accidents whic dont even Resemble eachother. The Instruments on this flight were working(On the Previous flight the Captains Instruments were Showing unreliable Indications whic was looked at by MX before the Accident Flight)
Really, your basing your opinion on ACI whic is a complete overdamatization of the Smallest Thing? Have you ever worked as a Aeronautical Engineer or do you know anyone that is one? No one "Carelessly" Fixes planes these Days. You have to exactly follow the AMM Tasks and get the Task signed off, you cant just go to a plane and do something and call it a job done, Goodluck with that. What is your Claim of Understaffing and pressure based on? Do you have any Graphs, Data or Anything at all to back that claim up, or just ACI?
2 Crews Faced with the Same Situation, 1 Crew were able to Handle the Issue, the other weren't. Go Figure.
A Single Human error doesnt cause a Crash, its a Chain of errors and also down to the Skill of a Person. I'm sorry to say but so many People are Pilots because they have the money when in reality they shouldn't even be allowed to touch something. Every Plane is objected to Multiple Maintenace Checks like C/D-Checks where its Torn appart and Every Inch is inspected. Those inspections dont happen randomly, They happen after xxxx Hours and Every airline keeps track of that. so a Plane going in for Maintenance Checks does not Cause a delay at all cause it's planned. 99% of the Cases theres always a Backup plane that can be flown in from somewhere or it's standing around at the airport to replace the "Faulty" one its not as big of a deal as you make it out to be. And no plane get's grounded for "minor" issue, if there is one, it's written up in the Tech Log and fixed on the next annual Check. it doesnt cause a delay and there is no reason to not tell of something thats faulty. I can tell you that The major western airlines dont Skimp their Maintenance, there is almost no Grey area, If you see that something is Broken you consult the AMM and to the Task in there, no matter what.
Again this is so wrong. The Previous Crew wasn't aware of the MCAS system, they had however Unreliable SPD and ALT on the Cpt. Side, so they thought the Trim Runaway was because of that whic they have Reported to Maintenance. Maintenance Flushed the ADM's (Air Data Modules) and the Cpt. Pitot Tube, did Tests whic Worked Ok and they cleared the Plane. No one was even suspecting a faulty AOA Vane.
I'm sorry but it doesnt Take a genius to look Realize that you need to Pull back more and More to maintain the Pitch attitude, give it some NU Trim to ease of the Yoke Forces only to feel the Nose wanting to go down again. You'd look down on the Trimwheel and see it Run away from you(Whic btw. on the 737 is Loud). Whic is what the Crew on the Previous Flight managed to do.
Except that the Upsets in QF72 happened within Seconds and caused Abrupt sharp movements. Because of a Faulty AOA sensor
Liekly, but theres more to it than Just shifting the blame to the Pilots.
There is no "Auto-Trim" on a 737, you have MCAS(Only on the MAX) and the STS(Speed Trim System). Also this Cut off Switch as you've been Refering to (Proper name is: Stabilizer Trim Cutout Switches, of whic there are Always 2, one for the Main Electrical Channel and one for the Autopilot Channel) has been in the 737 since the Very first 737, if you were only fammiliar with legacy 737s then you would Exactly know where your 2 Cutout switches are. Wherever you got that Info From, its complete BS. The Stabilizer Cutout Switches and their Function are also Mentioned in the FCOM(Flight Crew Operating Manual) Whic every pilot will atleast have seen when they do their TypeRating. They had the Time, the crew before them Managed to stop the Runaway.