Hmmm.
Always a difficult situation.
Your last post is helpful in clarifying the some attitudes and from your original post there is also some helpful information.
You say that you have now enough experience, you think, to take on more ownership of the projects and that at the same time, you have started to question some of his decisions.
I would leave the past decisions well alone. Bringing them up will signal to him that you are out to get him (that's how he will see it).
Stick exclusively to current projects.
When you adopt a contrary position to him and where you both have solutions on the table, there are two ways forward.
The first is:
"Here is how I thought we should do it and why I thought that, can you please explain to me why I am wrong."
The second is:
"You are wrong. This is the right way to do it. Let me explain why." (and I am making damn sure management knows it too).
You need to know what your end objective is and find the right path to it.
You also need him to understand your objectives and that you are non-threatening, maybe even you are positive benefit to him.
Forget the engineering.
This is about people.
There are many many people in positions of seniority who are far less equipped to do the job than their juniors or that their juniors do.
Its a fact of life.
It is also a fact of life that they are probably very good at defending their position by whatever means.
They can either feel threatened:
"This guy wants my job and he is going to suck up to management and brown-nose me out of it trying to show them he knows far better than me."
Or they can feel:
"At last I have someone who can do the job and I now have my chance to get into management."
Down one path lies the possibility of a pyrrhic victory, you show him up to be a dunce but management decide you are don't have the right "character/personality" to be a "team player".
There is also the chance that he can either do it to you before you do it to him or that he will so damage you that you really don't have much of a future.
At best they will replace him with someone else.
At worst, they may let you go, whatever happens to him.
never expect management to do what you think they should do. They will surprise you every time. And never ever expect them to make the right decision, except by accident. This is a "hope for the best but expect the worst" approach to life.
Or he can decide he can work with you.
If you don't threaten, he may feel that he can gradually let go and let you take that responsibility you think you are now upto.
Life is going to be one long succession of people in authority over you who can't do your job as well as you can. They probably also can't do their job as well as you could.
So, we already know your first objective, to be able to take ownership of these projects.
Maybe your next objective is to have his job. That's OK, but you may find the easiest way to get his job is if he helps you to get it. He'll do that if he thinks you are going to help him move up the ladder.
How do your actions and attitudes signal which of these is the option you want to pursue?
The safest place for this guy, you may feel, is out of the door.
In reality, management often don't take such extreme measures. As you go through life you will see time and again where deadbeats and liabilities, instead of being shown the door, are promoted to where they can't do too much damage or moved sideways.
The path of least resistance may thus be to get him promoted out of your way.
He may have an ambition to get into management (especially if he is worried he doesn't have the skills he needs for where he is) But till now he has lacked the team and team player skills to do well enough to get there.
Management judge him by the team's results, not by his personal skill at a particular role (and till now they appear to have been OK with what he has done).
In fact they probably really don't care so long as they make the end of the month figures. They don't like spats between their troops. They hate to have to make difficult personal decisions. They will talk about "team players" a lot.
So, if he can be made to feel safe, that he at last has an engineer in his team he can safely trust:
(a) to do most of the engineering, and
(b) who isn't trying to stab him in the back all the time,
he can start to demonstrate management skills by managing you and letting you do more of the engineering.
He then can demonstrate at a last having a team that really delivers.
What happens then?
Well he goes into management (and let's face it, there are plenty of bad managers so one more won't make any difference) and you get his job.
There is a catch 22 here that works for you.
To at last show he has management potential, he has to deliver better results from his team. But once those results start rolling in, management won't want to do anything, such as promoting him, that will affect those results.
He therefore finds it is necessary to persuade management that if he moves up that you are the right guy to take over and maintain the performance of that department - "I've taught him all I know.". And management will want to feel assured that he can, as and when and for as long as necessary, provide a hands off supervisory role.
Life is never going to be simple. Black and white. Right and wrong.
JMW