Commercial Fixed Wing
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Deviation / Discrepancy - Procedural Hazardous Material Violation; Deviation / Discrepancy - Procedural Published Material / Policy
Aircraft Equipment Problem Dissipated; Flight Crew Became Reoriented; Flight Crew Overcame Equipment Problem
Human Factors
As [aircraft] was being loaded; a cart was brought to my airplane that contained a bunch of dry ice boxes. 16 boxes in total; each containing a reported 18kg of dry ice. I multiplied 18 by 16 and got 288kg. I remembered that there had been an alert bulletin released recently that limited the  Aircraft X to what I thought I remembered was 320kg of dry ice; and I confirmed this number with a pilot standing near me. However I didn't recall that the limit was in pounds; not kilograms. So I completed the PNF; submitted it to Dispatch via email and completed the flight as scheduled. I then received an email several days later from the director of safety asking to confirm the weight of the dry ice; we spoke on the phone and he informed me that the limit was in fact 320lbs and not 320kg. We discussed the issue and I now have this number etched in my brain.[Weight limit issue clarified] when the director of safety spoke with me on the phone about the discrepancy.[Captain further stated the following statements]. Instead of breaking out my GOM or confirming in the hazmat binder; I verbally discussed the weight with another pilot and thought that 320kg was the correct limit for the  Aircraft X. This was compounded by the fact that the jet was several hours late and thus everyone was in an enormous rush to get the cargo loaded and sent on its way.I felt rather crestfallen; as I pride myself on doing everything in exactly the same way and by the regs/procedures to the letter. When in doubt I will always refer to documentation in the future instead of verbally discussing it with someone or relying solely on my memory.Confirming with actual paperwork instead of verbally with another pilot. As I am the PIC the responsibility falls directly on my shoulders to ensure each flight is flown in compliance with company policy/procedure and the FARs and I shouldn't rely on my own memory and word of mouth information when I have questions with regard to important matters such as this.
Captain reported aircraft departed without positive confirmation of Hazmat cargo limitation. Limitation later confirmed cargo within limitations.