I will be enable to call you back vs I won't be able to call you back

Some examples from the web:

• If set to false the hero will be enable to earn or spend energy.
• To this effect, the EPLP can support the measures introduced to enable the right of call-back and sunset clauses contained within this directive, which is not an imposition on national powers.
• I have to call you back because he just came in.
• Tell them to call you back when they know where he is.
• I totally forgot to call you back.
• I'll have to call you back.
• But I think I need to call you back.
• Sorry, I'll have to call you back.
• I'm sorry. I forgot to call you back.
• It took long enough to call you back.
• Sorry, I'll have to call you back.
• Billy asked me to call you back.
• - I have to call you back.
• That particular dog of war will have to call you back after his bath.
• I completely forgot to call you back.
• Deena, seriously, I will call you back later.
• I will tell them to call you.
• I have to call you back on that, but the money sounds like we're in the ballpark.
• Sorry, I'll have to call you back.
• Great. Listen, I need to call you back in an hour.

Some examples from the web:

• I won't be able to call you for some weeks or even months.
• But even Sonny won't be able to call off Luca Brasi.
• And you won't be able to call him a liar because you'll have a bullet in your head.
• And you won't be able to call it if you're not authorized, so I'll get to security, I'll send it up.
• I told you I wouldn't be able to call you on your honeymoon, but you lied to me.
• I wouldn't be able to call myself a Christian if I didn't pardon you on the remainder of your sentence.
• - Call Aunt Irma and tell her I won't be able to make it.
• Boris may need me on short notice in the near future, and I won't be able to reach you after he calls.
• - I just did something stupid. I told my secretary to call Mother. I realized she won't be able to reach her.
• There was no phone in that dump, so I knew you wouldn't be able to call from t road to... to make sure I wasn't lying.
• And that's when you assaulted him so he wouldn't be able to call the cops on you?
• Soon I won't be able to fix your jacket.
• Although I won't be able to visit every month.
• And I'm afraid I won't be able to keep up.
• With my ankle I won't be able to move fast enough.
• I won't be able to walk.
• Otherwise, I won't be able to start...
• I won't be able to lean over to shut the door.
• I won't be able to get to the nearest Stargate for at least a month.
• I won't be able to relax.