Three years ago I was pulled over for supposed loud music violation. I submitted to a field sobriety test, which I thought I passed but the officers, eight in total still wanted a breathalyzer test. They pulled out one, then another officer said they should use the one in his trunk. I was fully cooperating but these officers were just looking for a reason too haul me in. I politely asked to do a blood draw, while not refusing anything. They were not happy about this. Fast forward a few months, I'm not a lawyer so I hired one. The lawyer was able to get all the charges dropped because the stop was unconstitutional.
So wait, you were arrested but then was a blood draw or breathalyzer ever actually completed? I'm talking about the breathalyzer at the station that's usually mounted to a table, not one of the portable field sobriety kits. If you did, unconstitutional or not there should be a BAC report. Whether the BAC report still exists depends on the state and their data retention requirements but the prosecutor's office may still have it. If they didn't then the FAA probably wants to know why one wasn't done. If you refused the official breathalyzer or blood draw, then the FAA considers that the same as being guilty. If one wasn't done as a procedural error or if the report no longer exists, then you have a little more to stand on but it's still going to be a difficult time. You'd probably need a letter from the prosecutor stating no test was ever conducted or that the report was destroyed. Even that may not be enough.
Why don't you get the arrest expunged?
His line "I learned a lesson" is a tell IMO.
The lesson may have just been not to comply with police looking for a DUI. Exercising one's 5th amendment rights is unfortunately considered to be the purview of the guilty and so most people comply with officers questions and requests, especially on a traffic stop. It takes only one situation such as this for people to learn that an officer conducting an investigation is not your friend; they can and will legally lie to you and admitting anything can solidify the prosecution of the case.
Contrary to popular belief, field sobriety tests are completely optional and the field breathalyzers are notoriously inaccurate and are generally not considered admissible in court except to prove probable cause for the arrest. Still any lawyer worth his salt would tell you not to comply with a DUI stop. Complying with the field sobriety tests is akin to testifying against yourself. If you fail any of them, they can and will be used against you in court and to provide probable cause for your arrest which allows the official "legal" test to be requested/completed. If you dont comply with the field sobriety test, then the officer must show that the reasonable suspicion of a DUI rose to the level of probable cause for arrest and search for the blood draw/breathalyzer and it may not even get that far if the officer doesnt think it'll stick.
Without corroborating evidence of a failed field test, a lawyer can challenge the arrest and potentially the blood sample or breathalyzer if you provided one or were ordered to provide one by the court. Of course the same attorney would advise you also refuse to the breathalyzer and blood draw too since in the criminal proceeding its harder for the prosecution to get a conviction with no evidence but you do put your Commercial Driver's and/or Pilot License at risk.
Only a blood draw or a breathalyzer test taken using the official, permanently installed machine at booking and administered by a trained technician provides the legal basis for DUI. If you are arrested and taken in, you can still refuse to comply with this test however most states have a "implied consent" penalty for refusing this test. The federal government also uses implied consent for the purpose of Commercial Drivers Licenses and Private (or higher) Pilot Licenses so a failure to blow on the official test may lead to a suspension anyway. Still if there's a chance you'll fail, its easier to win the criminal case when the prosecution has no physical evidence showing you were driving under the influence.
