If we are looking at a Taiwan scenario then China will certainly not deal with older MANPADS. They will deal with the latest ones. Plus, Taiwan has a large reservist force which will be mobilized before the war. These reservists armed with MANPADS can do a missile barrage that no helicopter will be able to defeat. So, I don't think those Helicopters will be useful in an actively defended beach landing.
They might be useful if the landing is not on the beach but much more inside for a surprise transport of troops. Of course Air superiority is essential to defeat all high end SAM sites. But after that part is over. PLA might want to land behind enemy lines with helicopters instead of doing a beach landing that could be heavily defended. With high altitude, Helicopters can probably beat MANPADS.
I don't think Helicopters are useful against modern Ships with good radars. Their nap the earth Strategy will be ineffective when they get to around 20 miles of a ship. Then, they will be within the earth's curvature horizon and easily visible to the ship radar. Most helicopters have missiles with very low range. The moment they are visible by ships radar, they will be shot down with air defense missiles. Plus helicopters are too slow to avoid ship based SAM missiles.
Without drifting into the helicopter threads, I'll just quickly add these points:
- Aided by radar/missile/laser warning receivers combined with chaf/flare and infrared countermeasures, I'm confident a PLA helo pilot has the tools and sufficient reaction time to perform effective evasive maneuvers when fired by a MANPAD.
- I have no idea what the PLA doctrine is, but I'm almost certain no Z-10 or Z-19 would be flying alone - They'd almost certainly fly in tandem, if not in greater numbers. If they detect a missile being fired upon them, it only takes one helo to turn to where the missile was fired from and lay waste to it with rockets/mow down opposing troops.
- Target acquisition and launching of a MANPAD takes time. While an attack helicopter might be slower than a Harrier or an F-35B, it still has the ability to fly fast at 100 something knots. A soldier still needs to seek out the helo, find a good spot to fire the MANPAD, place said MANPAD on his/her shoulder, anticipate where the helo is going, and ultimately fire the weapon.... That's a long time, certainly enough time to be identified as a hostile by troops on the ground or the eye in the sky, by which they will be greeted/neutralized by the barrel of a Type 96 tank or the Z-10's plethora of weapons. Like I said it takes five fingers to form a fist, especially in joint warfare.
The fact the Type 075 can bring multiple helicopter platforms to a battlefield in tandem with landing troops from the Type 071 is absolutely a game changer.