Rubber Dogshit
I've been trying to keep up with the Boeing fiasco ever since the second crash of the new 737 MAX last weekend. Oddly enough I have found that my own experiences in my four years of Vietnam-era draft avoidance back in the late 60's and early 70's have been an enormous help in my understanding of the situation. I joined the U.S. Air Force in late 1967 on the promise that I would be trained as an airborne weather equipment specialist. That never happened but the Air Force was nice to me anyway. They set me up in a training school in Illinois and taught me enough for me to be qualified to work in certain large aircraft navigation and autopilot shops and then they sent me to North Dakota for a winter while I got my feet wet by working on their latest model, the H model, of Boeing-built B-52 bombers and KC-135 refueling tankers.
After that winter, which still holds the distinction as the coldest winter of my life, the Air Force transferred me to Fort Worth, Texas where I worked in a brand new avionics shop, the first ever avionics shop for the then brand new FB-111A. It was there in Fort Worth that I spent the hottest summer of my life. If it ain't the cold it's the heat, eh?
So while we waited in Fort Worth for deliveries to begin of the new FB-111A's we did maintenance on a fleet of older B-52 D models that were rotating out to Guam for use in the bombing campaign in the Vietnam War. Those old planes rotated out for six months of use in the war but they never came back to our base again. We were by then an FB-111A base. Before they left, though, and mind you this is from old memories which may by now be flawed, but I do have a memory of being taken out to the flight line by a couple of older technicians in my avionics shop and being required by them to crawl through a small opening into the back section of a B-52 fuselage near the tail while the plane sat on the flight line in early Texas summer sunshine and as quickly as I possibly could so I would not succumb to heat stroke swapping out a faulty horizontal stabilizer pitch trim jack screw. It was when the corresponding horizontal stabilizer pitch trim jack screw in the 737 MAX was located in the wreckage of last weeks crash in Ethiopia and found to be in its full nose down trim location that it became clear that this recent accident was probably caused by the same glitch that caused the crash back in October of the Lion Air 737 MAX.
Basically it appears that these airplanes both crashed when a new avionics system malfunctioned and fought against pilot authority while the system - not the pilots but the automatic flight control system itself - attempted repeatedly to initiate a slow, large radius inverted loop, a stunt you wouldn't even see a test pilot attempt in an airplane like this, an airshow stunt that you won't find in any of the videos of these planes when they appeared at air shows over the past few years - an inverted negative-G loop that begins with a power-on pitch down command generously offered up by whoever did the computer programming for this new 737 version.
The system itself, unique to the Boeing 737 MAX design, is referred to as MCAS or Maneuvering Characteristics Augmentation System. According to these visuals which appear to have official Boeing origin, the MCAS system is activated when the airplane is satisfying four parameters:
So why did Boeing think it was worth the risk to implement this system into this new design?
Good question.
Plug your nose people because the answer stinks.
From everything I have been able to gather, Boeing implemented this system, gave it a new name and built it into this new version of the 737 to compensate for an aerodynamic shift from the previous model 737 caused by the upgraded engine, an engine whose size didn't allow for the same engine mount as the previous 737 engine mount. To keep the engine up away from the ground sufficiently when the airplane is being operated on the ground, Boeing designers moved its position on the wing both forward and up, not by a lot but some, apparently by enough.
The claim seems to be that this new engine location had an effect on the flight characteristics of this new 737 variant. Boeing wanted to roll out this new model and have existing 737 pilots - pilots trained and experienced in the previous 737 design - have these experienced pilots be able to just step into these new planes and find them so familiar that no additional flight training would be required. It was a sales pitch. So here, Mr. or Ms. airline pilot, you are already trained and qualified in the 737, you're fine to go in this new design. Flies just like what you're already used to flying.
Except...
We're not going to worry you by informing you that we have made a bit of a change to this thing and added a new automatic system that has never been tried before in airliner design. And oh, we don't want to alarm you so we just won't tell you about this new system.
I shit you not!
Pilots are coming out and blowing the whistle on Boeing and pointing out to each other and to the general public and pointing out to anyone else that will listen that pilots were not informed of this new system and were not given training on how to handle the airplane if this system fails. To make things even worse, most pilots didn't have access to flight simulators for this new model so they had no way to prepare themselves for when this system failed. And apparently it did fail in at least two of these new airplanes. Both times the failure overcame any prior 737 pilot training and all on board these two airplanes were killed.
So that's what I've come up with so far in my Google-driven self-education.
There has been quite a lot of discussion about what should these pilots have done to survive this malfunction. What did they do? Why didn't it work for them? And what should they have done instead?
So far nobody has answered these questions. Both in the Indonesia crash last October and in this month's crash in Africa there should be answers to the question what did the pilots do. Those answers should be in the black boxes that automatically record all flight control commands but so far that information hasn't been released. So all I have to go on so far is common sense and speculation, both highly influenced by speculation and system familiarization being generously offered by others on the Internet.
The general consensus of others seems to be that these pilots should have recognized the problem as somehow being introduced and enabled by electrical pitch trim circuits. So the pilots should have turned off those circuits. The consensus is that if they did that then it would stop this pitch trim system from forcing the airplane into a pitch-down condition, this inverted loop condition I spoke of earlier.
That makes sense, right? That's a good knee-jerk first response. Just turn it off.
Except...
And it gets tricky here, counterintuitive...
Turning this system off disables switches located prominently on each pilot's yoke that give the pilots control of pitch trim. Turning the system off by turning off the bypass switches disables the very mechanism that these pilots were probably using to control their airplanes. How so? Well it would appear that when either the pilot or the copilot use these yoke-mounted pitch trim switches, that momentarily disables the new MCAS system - key word momentarily.
So let's say that either the pilot or the copilot did overcome the death-defying MCAS system momentarily using these yoke-mounted controls. Then what?
Well if they held these buttons down, then the pitch trim would go to a nose up condition, initiating a nose-up positive G loop. Oops! Time to let go! So they let go. Meanwhile the malfunction continues and the MCAS system triggers again and the negative-G loop starts again.
So what to do???
If you don't shut off the bypass switches and disable the electric pitch trim circuits then the problem persists.
If you do shut off the bypass switches then you no longer can save the airplane by using the yoke pitch trim switches. You have to do it by hand by cranking the pitch control wheels. That's more than likely not something a pilot can do quickly enough to save the airplane if the malfunctioning MCAS system has sent pitch trim to maximum nose down.
So what do you do?
Nobody seems to know yet what the pilots did choose to do. So far that's either still a secret or it was never recorded in the black boxes to begin with. That seems unlikely so the rational explanation seems to be it's still a secret.
The granddaughter of the sister of well-known consumer advocate Ralph Nader was killed in the crash last week. She was on board the Boeing 737 MAX that crashed last Sunday in Ethiopia and she was killed in that crash. So it's not likely that it will go over well if Boeing or the government or the airlines try to keep secrets. No doubt all authorities involved will want to keep secrets but that's the one remaining mistake they can make. If they keep secrets, then public trust in Boeing, public trust in the government agencies tasked with protecting passenger safety, and public trust in the airline industry in general will all suffer.
Already the flying public has lost trust in the airplane. There are a lot of people who are reacting to this by committing themselves to never fly on a 737 MAX. Most people will probably generalize and never fly again on any Boeing 737 of any vintage. Some will never fly in a Boeing airliner again, like EVER! Never ever!
If you've ever watched the movie Top Gun where actor Tom Cruise plays a Navy F-14 pilot there's a line early in the movie where after Tom Cruise pulls a stunt in his F-14 his commander calls him and his teammate in for a good reaming out and the commander assures them that if they ever do that again they'll be flying rubber dog shit out of Hong Kong for the remainder of their flying careers. I've been thinking, if Boeing screws this up, these new 737 MAX airplanes will have to be relegated to a similar use. Nobody will trust them as airliners again.
It's too bad too. There's a good chance that this airplane, this 737 MAX, is the best and the safest airliner ever manufactured by anyone bar none. It was destined for that reputation. But these two crashes and if it comes to it future crashes caused by this new MCAS system will most certainly destroy that legacy before it even can develop. The fleet, if it is not physically destroyed by executive order, will have to find other applications other than as passenger airplanes.
Like what? Top Gun is an old movie. The F-14 is retired now. We can assume that rubber dog shit is no longer produced in Hong Kong. So what other use?
They could become military refueling tankers to replace the aging KC-135, a relic of the 1960's still serving around the world. That's one possibility. Put a big fuel tank down under the main deck and this airplane could serve as a gas station in any sky anywhere around the world.
They could become cargo airplanes. Maybe Amazon could use them or UPS.
Here's a thought. President Trump could order a bunch of them to ferry illegal immigrants back to their country of origin. Or maybe initiate flights to transport undocumented immigrants down to Venezuela, drop them off down there and on the return trip ferry in properly documented green-card holding immigrant workers. That would put a lot of these brand new airplanes back into service. Plus it would restore Boeing's reputation if none of these 737 MAX planes that nobody trusts anymore ever crashed again despite heavy use.
So there are ways to get beyond this Boeing nightmare. But keeping secrets about the real cause of these crashes is nothing short of corporate suicide. Ralph Nader will make sure of that.
By the way, I haven't brought this up yet but this new system, this MCAS system, it isn't new. It is a rose by another name but it isn't new. For years the aviation industry has wanted to install systems on airplanes that would overpower pilots who bring their airplanes too close to wing stall conditions. When a wing stalls it loses its lift and causes the airplane to either quit climbing or start falling. Automatic systems that electrically command a pitch down maneuver without the pilot's consent whenever his airplane approaches a stall do exist and are included in some general aviation autopilot systems. Up until now they have been deemed too risky for the airline industry. Why else do you suppose the MCAS system was designed not to operate when flaps are down? After all, flaps are down when the airplane is being flown close to the ground, in takeoff and landing situations and in slow low-level approaches. That's when most fatal stalls occur so why disable the system then? Because it's such a risky thing to program an airplane to pitch itself down when it's already flying close to the ground, that's why.
It's dangerous!
Anyway, let me give that link again...
What is the MCAS system?
Oh and as to the question what should the pilots have dome? What could they have done to save their airplanes? How should they have shut down this MCAS system long enough to get the airplanes safely back to the airport?
I don't know but why not extend the flaps a little and see if that shuts MCAS off?
Just a thought...
It's too late now to do that, or at least let's hope it is. Let's hope that Boeing removes MCAS entirely from these airliners. But if they insist on keeping it, why not train pilots to instinctively extend some flaps to safely disable a malfunctioning MCAS?
Break the code of secrecy. Inform pilots of the system and train them how to survive when the system malfunctions.
Just a thought...
After that winter, which still holds the distinction as the coldest winter of my life, the Air Force transferred me to Fort Worth, Texas where I worked in a brand new avionics shop, the first ever avionics shop for the then brand new FB-111A. It was there in Fort Worth that I spent the hottest summer of my life. If it ain't the cold it's the heat, eh?
So while we waited in Fort Worth for deliveries to begin of the new FB-111A's we did maintenance on a fleet of older B-52 D models that were rotating out to Guam for use in the bombing campaign in the Vietnam War. Those old planes rotated out for six months of use in the war but they never came back to our base again. We were by then an FB-111A base. Before they left, though, and mind you this is from old memories which may by now be flawed, but I do have a memory of being taken out to the flight line by a couple of older technicians in my avionics shop and being required by them to crawl through a small opening into the back section of a B-52 fuselage near the tail while the plane sat on the flight line in early Texas summer sunshine and as quickly as I possibly could so I would not succumb to heat stroke swapping out a faulty horizontal stabilizer pitch trim jack screw. It was when the corresponding horizontal stabilizer pitch trim jack screw in the 737 MAX was located in the wreckage of last weeks crash in Ethiopia and found to be in its full nose down trim location that it became clear that this recent accident was probably caused by the same glitch that caused the crash back in October of the Lion Air 737 MAX.
Basically it appears that these airplanes both crashed when a new avionics system malfunctioned and fought against pilot authority while the system - not the pilots but the automatic flight control system itself - attempted repeatedly to initiate a slow, large radius inverted loop, a stunt you wouldn't even see a test pilot attempt in an airplane like this, an airshow stunt that you won't find in any of the videos of these planes when they appeared at air shows over the past few years - an inverted negative-G loop that begins with a power-on pitch down command generously offered up by whoever did the computer programming for this new 737 version.
The system itself, unique to the Boeing 737 MAX design, is referred to as MCAS or Maneuvering Characteristics Augmentation System. According to these visuals which appear to have official Boeing origin, the MCAS system is activated when the airplane is satisfying four parameters:
- The airplane's angle of attack is high
- The autopilot system is off
- The flaps are up (meaning they are not extended in their takeoff/landing position)
- The airplane is "steeply turning"
So why did Boeing think it was worth the risk to implement this system into this new design?
Good question.
Plug your nose people because the answer stinks.
From everything I have been able to gather, Boeing implemented this system, gave it a new name and built it into this new version of the 737 to compensate for an aerodynamic shift from the previous model 737 caused by the upgraded engine, an engine whose size didn't allow for the same engine mount as the previous 737 engine mount. To keep the engine up away from the ground sufficiently when the airplane is being operated on the ground, Boeing designers moved its position on the wing both forward and up, not by a lot but some, apparently by enough.
The claim seems to be that this new engine location had an effect on the flight characteristics of this new 737 variant. Boeing wanted to roll out this new model and have existing 737 pilots - pilots trained and experienced in the previous 737 design - have these experienced pilots be able to just step into these new planes and find them so familiar that no additional flight training would be required. It was a sales pitch. So here, Mr. or Ms. airline pilot, you are already trained and qualified in the 737, you're fine to go in this new design. Flies just like what you're already used to flying.
Except...
We're not going to worry you by informing you that we have made a bit of a change to this thing and added a new automatic system that has never been tried before in airliner design. And oh, we don't want to alarm you so we just won't tell you about this new system.
I shit you not!
Pilots are coming out and blowing the whistle on Boeing and pointing out to each other and to the general public and pointing out to anyone else that will listen that pilots were not informed of this new system and were not given training on how to handle the airplane if this system fails. To make things even worse, most pilots didn't have access to flight simulators for this new model so they had no way to prepare themselves for when this system failed. And apparently it did fail in at least two of these new airplanes. Both times the failure overcame any prior 737 pilot training and all on board these two airplanes were killed.
So that's what I've come up with so far in my Google-driven self-education.
There has been quite a lot of discussion about what should these pilots have done to survive this malfunction. What did they do? Why didn't it work for them? And what should they have done instead?
So far nobody has answered these questions. Both in the Indonesia crash last October and in this month's crash in Africa there should be answers to the question what did the pilots do. Those answers should be in the black boxes that automatically record all flight control commands but so far that information hasn't been released. So all I have to go on so far is common sense and speculation, both highly influenced by speculation and system familiarization being generously offered by others on the Internet.
The general consensus of others seems to be that these pilots should have recognized the problem as somehow being introduced and enabled by electrical pitch trim circuits. So the pilots should have turned off those circuits. The consensus is that if they did that then it would stop this pitch trim system from forcing the airplane into a pitch-down condition, this inverted loop condition I spoke of earlier.
That makes sense, right? That's a good knee-jerk first response. Just turn it off.
Except...
And it gets tricky here, counterintuitive...
Turning this system off disables switches located prominently on each pilot's yoke that give the pilots control of pitch trim. Turning the system off by turning off the bypass switches disables the very mechanism that these pilots were probably using to control their airplanes. How so? Well it would appear that when either the pilot or the copilot use these yoke-mounted pitch trim switches, that momentarily disables the new MCAS system - key word momentarily.
So let's say that either the pilot or the copilot did overcome the death-defying MCAS system momentarily using these yoke-mounted controls. Then what?
Well if they held these buttons down, then the pitch trim would go to a nose up condition, initiating a nose-up positive G loop. Oops! Time to let go! So they let go. Meanwhile the malfunction continues and the MCAS system triggers again and the negative-G loop starts again.
So what to do???
If you don't shut off the bypass switches and disable the electric pitch trim circuits then the problem persists.
If you do shut off the bypass switches then you no longer can save the airplane by using the yoke pitch trim switches. You have to do it by hand by cranking the pitch control wheels. That's more than likely not something a pilot can do quickly enough to save the airplane if the malfunctioning MCAS system has sent pitch trim to maximum nose down.
So what do you do?
Nobody seems to know yet what the pilots did choose to do. So far that's either still a secret or it was never recorded in the black boxes to begin with. That seems unlikely so the rational explanation seems to be it's still a secret.
The granddaughter of the sister of well-known consumer advocate Ralph Nader was killed in the crash last week. She was on board the Boeing 737 MAX that crashed last Sunday in Ethiopia and she was killed in that crash. So it's not likely that it will go over well if Boeing or the government or the airlines try to keep secrets. No doubt all authorities involved will want to keep secrets but that's the one remaining mistake they can make. If they keep secrets, then public trust in Boeing, public trust in the government agencies tasked with protecting passenger safety, and public trust in the airline industry in general will all suffer.
Already the flying public has lost trust in the airplane. There are a lot of people who are reacting to this by committing themselves to never fly on a 737 MAX. Most people will probably generalize and never fly again on any Boeing 737 of any vintage. Some will never fly in a Boeing airliner again, like EVER! Never ever!
If you've ever watched the movie Top Gun where actor Tom Cruise plays a Navy F-14 pilot there's a line early in the movie where after Tom Cruise pulls a stunt in his F-14 his commander calls him and his teammate in for a good reaming out and the commander assures them that if they ever do that again they'll be flying rubber dog shit out of Hong Kong for the remainder of their flying careers. I've been thinking, if Boeing screws this up, these new 737 MAX airplanes will have to be relegated to a similar use. Nobody will trust them as airliners again.
It's too bad too. There's a good chance that this airplane, this 737 MAX, is the best and the safest airliner ever manufactured by anyone bar none. It was destined for that reputation. But these two crashes and if it comes to it future crashes caused by this new MCAS system will most certainly destroy that legacy before it even can develop. The fleet, if it is not physically destroyed by executive order, will have to find other applications other than as passenger airplanes.
Like what? Top Gun is an old movie. The F-14 is retired now. We can assume that rubber dog shit is no longer produced in Hong Kong. So what other use?
They could become military refueling tankers to replace the aging KC-135, a relic of the 1960's still serving around the world. That's one possibility. Put a big fuel tank down under the main deck and this airplane could serve as a gas station in any sky anywhere around the world.
They could become cargo airplanes. Maybe Amazon could use them or UPS.
Here's a thought. President Trump could order a bunch of them to ferry illegal immigrants back to their country of origin. Or maybe initiate flights to transport undocumented immigrants down to Venezuela, drop them off down there and on the return trip ferry in properly documented green-card holding immigrant workers. That would put a lot of these brand new airplanes back into service. Plus it would restore Boeing's reputation if none of these 737 MAX planes that nobody trusts anymore ever crashed again despite heavy use.
So there are ways to get beyond this Boeing nightmare. But keeping secrets about the real cause of these crashes is nothing short of corporate suicide. Ralph Nader will make sure of that.
By the way, I haven't brought this up yet but this new system, this MCAS system, it isn't new. It is a rose by another name but it isn't new. For years the aviation industry has wanted to install systems on airplanes that would overpower pilots who bring their airplanes too close to wing stall conditions. When a wing stalls it loses its lift and causes the airplane to either quit climbing or start falling. Automatic systems that electrically command a pitch down maneuver without the pilot's consent whenever his airplane approaches a stall do exist and are included in some general aviation autopilot systems. Up until now they have been deemed too risky for the airline industry. Why else do you suppose the MCAS system was designed not to operate when flaps are down? After all, flaps are down when the airplane is being flown close to the ground, in takeoff and landing situations and in slow low-level approaches. That's when most fatal stalls occur so why disable the system then? Because it's such a risky thing to program an airplane to pitch itself down when it's already flying close to the ground, that's why.
It's dangerous!
Anyway, let me give that link again...
What is the MCAS system?
Oh and as to the question what should the pilots have dome? What could they have done to save their airplanes? How should they have shut down this MCAS system long enough to get the airplanes safely back to the airport?
I don't know but why not extend the flaps a little and see if that shuts MCAS off?
Just a thought...
It's too late now to do that, or at least let's hope it is. Let's hope that Boeing removes MCAS entirely from these airliners. But if they insist on keeping it, why not train pilots to instinctively extend some flaps to safely disable a malfunctioning MCAS?
Break the code of secrecy. Inform pilots of the system and train them how to survive when the system malfunctions.
Just a thought...
posted by Bill | 4:16 AM
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