If you look at 2016 aviation baseline, you’ll see that about 8 percent — 54 of 661 — of American Airlines’ flights out of its big Charlotte hub are still on turboprops. These are rather old planes that are unloved by passengers. The question has been for some time what will replace them. We now have an answer of sorts: Piedmont Airlines, which is wholly owned by American Airlines and operates the 37-and 50-seat turboprops on its behalf, has announced that their turboprops will be giving way to 50-seat Embraer regional jets, with all the turboprops expected to be all gone by 2020.

This is just kicking the can down the road for a couple of years though. Piedmont is getting planes that are far from new — by 2020, those new to them Embraers will be somewhere between 15 and 22 years old and soon themselves in need of replacement. Replaced by what may well depend upon the next round of contract negotiations between American Airlines and its pilots union, as the “scope” clause in the contract limits what type of planes and in what quantity American’s regional carriers can fly. American is currently near the existing cap on the much more efficient large regional jets (76-seat Embraer 175s or Bombardier CRJ900s) that its regional carrier can fly. If American can’t get the large regional jet cap raised, then Piedmont acquiring new, more modern turboprops may be an option as 50-seat regional jets have been out-of-production for over a decade.

Bonus impact: Turboprops can takeoff and land on much shorter runways than what regional jets require. This could be a problem for a couple of places Piedmont flies to — it’s uncertain at best whether Hilton Head, SC (to Charlotte) or New Haven, CT (to Philadelphia) can reasonably support regional jet service.