Passengers aboard Frontier Flight 4345 are recounting the frightening moments after the jet struck and killed a person on the runway Friday night, as federal investigators work to piece together what happened and whether evacuat ion procedures need to change.As of Monday afternoon, the National Transportation Safety Board said it still has not determined whether it will open a formal safety investigation. The agency said it is gathering information about the emergency evacuation process. The identity of the person killed has not been released.12 people suffered minor injuries during the evacuation."As the smoke filled the cabin that's when everyone really started to freak out, said passenger Levi Lynn.Mohamed Hassan, another passenger on Flight 4345, said the experience left him worried about lasting health effects."I'm just concerned for like myself and everyone's health because I mean like inhaled toxic fumes for like four minutes."The evacuation has drawn scrutiny over some passengers' behavior during the process. Sara Nelson, president of the Association of Flight Attendants, said it is deeply troubling when passengers do not follow crew instructions."It's extremely concerning when passengers do not follow the instructions to leave all their bags behind, Nelson said.Nelson said takeoff and landing are the two most critical phases of a flight, and crews are trained and ready to act during both."This is part of our commands for a reason. It's part of our safety briefing for a reason, Nelson said.Carry-on bags during evacuations have been a concern for federal regulators for years. Just last September, the FAA issued a Safety Alert for Operators in other words, a directive telling airlines to re-evaluate their evacuation procedures regarding carry-ons because of similar incidents. Watch Adria Iraheta's report in the player below: NTSB investigating Frontier flight evacuationPassengers have taken their carry-on items with them on a number of recent evacuations. This slows the evacuation and puts lives at risk. Carry-on items also can damage emergency slides, an FAA spokesperson told Denver7 on Monday.The SAFO recommends airlines:  Ensure safety briefings clearly and concisely instruct passengers to leave all carry-on items behind during an evacuation.   Conduct passenger outreach and education campaigns.  Leverage their Safety Management Systems (SMS) to evaluate evacuation procedures and identify and address any risks and hazards. The Association of Flight Attendants is also conducting its own investigation into the incident. Nelson said the union wants to identify what needs to change."Whether that's part of the training, whether it's part of the announcements, whether it's part of the briefings for the passengers as they are going through their whole process of buying the ticket, said Nelson. "As you're thinking about flying, have it in your head if I need to leave, I need to get up and go, not stop and grab a bag that could make everyone else burn on an airplane or make it impossible for myself to get off, too."Measures such as locking overhead bins during flights have been considered in the past but were never implemented due to safety reasons, Nelson said.The union is providing emotional support to cabin crew members not only to help them process the trauma and grief, but also to process the what-ifs like what they could have done differently during the evacuation process.All things considered, experts say the pilots and crew appear to have done everything they should have as part of the rejected takeoff saving many lives in the process.MSU Denver aviation expert Chad Kendall said the maneuver was a textbook example of what crews should do in case of an emergency.Rejecting at high speeds is a critical maneuver, but they performed it to their training. High remarks for how they responded, to the pilots and then the cabin crew members of getting all the passengers off safely, Kendall said.This story was reported on-air by a journalist and has been converted to this platform with the assistance of AI. Our editorial team verifies all reporting on all platforms for fairness and accuracy. ...read more read less