Air taxi flight crew reported undocumented Hazmat cargo loaded in cargo compartment without any required documentation provided to the flight crew. A communication breakdown between Captain and First Officer exacerbated the situation resulting in a safe precautionary air return to correct Hazmat violation and weight and balance errors.
Synopsis
Air taxi flight crew reported undocumented Hazmat cargo loaded in cargo compartment without any required documentation provided to the flight crew. A communication breakdown between Captain and First Officer exacerbated the situation resulting in a safe precautionary air return to correct Hazmat violation and weight and balance errors.
Narrative
We did the appropriate paperwork and prepared to depart ZZZ for ZZZ1. Picked up our clearance and departed. At some point in the climb we became aware of an odor distinctly that of gasoline. After discussing the notable lack of HAZMAT paperwork and the implications of such an odor we made the decision to turn around. Re-briefed the approach and our plan; called ZZZ Center and requested direct to the IAF for the ILS which we then performed as normal. After arriving back at the airport we opened the cargo door to inspect the cargo and locate the culprit. Upon doing so we discovered a shipment of gas cans (Jerry Jugs) that had not been cleaned properly. We removed them; searched the rest of the load for anything else that we should have been notified of its presence; removed what we could find; and redid the weight and balance. Filed a new flight plan; and departed once more for ZZZ1. The rest of the flight went without incident. A company mandated return report was filed with the appropriate operational personnel.
Second reporter narrative
I was the FO on Flight X. We arrived into ZZZ to get loaded. The Captain informed me we were picking up camera equipment that was a cargo charter. The ground crew loaded our plane and supplied the Captain where each [component] weight was located. He did a weight and balance and I checked his math and also agreed we were within CG. They did not supply us anything that showed Hazmat paperwork. However; I didn't know that at the time. I went and gathered the cones and when I went to grab the tail stand I noticed it was 1/2 inch off the ground which I have never seen. I notified the Captain on the aft weight being heavy and told him he should come look. He declined to come inspect the weight aft that was weighing down the tail stand but he checked the paperwork and said we would be OK. I did notice some gas cans which I believed to be brand new at the rear of the cargo area. I also noticed numerous large propane tanks. At this point I assumed the Capt knew about it.As we departed and were climbing out I started smelling a strong odor of gasoline. We were still in a critical phase of flight climbing out on our departure procedure. ATC cleared us direct ZZZZZ once 6000 feet. As we climb through 6000 feet clear of all obstacles I entered direct ZZZZZ in the GPS and then told the Captain I smelled a very strong odor of gasoline. He explained he did as well. We kept climbing trying to decide what was the odor exactly. I told him about the cans and propane tanks and asked if he knew if we had Hazmat onboard. He explained he was not told or given any Hazmat paperwork. We turned the blowers off as I was getting light headed from the fumes. I told the Captain I felt it was urgent we return to ZZZ or land at the nearest airport ZZZ2 to check the safety of our load and determine the odor. After a brief discussion the Captain agreed and we made the decision to return to ZZZ because there we had a better way of inspecting and checking for paperwork. The Captain notified ATC we needed to turn back to ZZZ due to odor coming from our cargo. We did our descent approach checklist after picking up current weather and started our approach into ZZZ. We landed safely in ZZZ. I got out and put the tail stand in immediately. When the Captain exited the aircraft the plane fell on to the stand. I told the Captain I was not leaving in that airplane until we got the load figured out and the weight and Balance was corrected. We went through and found approximately 10 gas cans that contained some gasoline left inside; flares; ammunition; bear spray; 100 small propane tanks; and 8 large propane tanks. None of them were on the manifest we were given. We removed those items. The Captain got a flashlight and went through most of the entire load. The Captain redistributed the weight making our plane safely within the CG limits. We left ZZZ without any Hazmat onboard to our knowledge and we were well within CG.I learned a valuable lesson in this. I will never assume the Captain knows what is inside the aircraft. When I ask a Captain to come look at the CG I will not start the flight until that Captain comes and we as a team can determine our aircraft is loaded how the loaders told us and we are not carrying Hazmat materials unaware to us. It was flooding rain. The Captain and I both trusted the plane was loaded the way and with the contents the loader told us. We were delayed in a few other places and allowed the pressure of getting the cargo to ZZZ3 and the fact we were pushing our time to rush us. Once the Captain and myself discovered all these discrepancies we both slowed down; ensured the load was legal. We notified Dispatch while flying back we would not be making it to ZZZ3 as planned. We both were not going to have enough hours and both of us were fatigued. Once we realized the issue we made the right decisions to make it safe. I learned a valuable lesson from this incident and the Captain explained he did as well.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.