All passengers from Avianca must ride a Mobile Lounge from the gate arrival area to IAB (immigration & customs). Try to stay close to the doors on the Mobile Lounge - so you can be among the first ones off at IAB.

First stop is Passport Control. Be sure to get into the correct line for either US Citizens or Non-US Citizens. (Note that Legal Permanent Residents - Green Card Holders - use the Citizen line.)

After Passport Control you must retrieve your checked bag from the carousel. There are free luggage carts to use if necessary.

Then head towards the EXIT, where you will surrender your blue Customs Form. (And hope that you aren't diverted for Secondary Processing.)

After surrendering the Customs Form, go straight through automatic double-doors. There is a currency exchange in front of you, if necessary. Then turn right in front of the currency exchange and head for the United re-check counter. At that counter you can re-check your checked bag, and get your boarding pass/gate information for your connecting flight.

Then exit through another automatic double-door into the domestic arrivals area. Look for the "TO ALL GATES" sign behind carousel 13. That leads you down to TSA security. After TSA security, follow the signs for transportation to the concourse (A, C, or D) for your connecting flight.

If your Avianca flight arrives on time, you should be fine with this connection.

Feel free to PM if you have any questions.