The interim report also revealed traces of cannabis had been found in the blood of pilot Lance Hopping, which while being a "significant safety concern" was unlikely to have caused the crash.
Media were told investigators would look at seven major lines of inquiry following the interim report, including whether a malfunction contributed to the crash, balloon and pilot performance, and the effects of substances on pilot performance.
The investigation also was focused on the certification and registration of balloons, the maintenance and continuing airworthiness of balloons, and a review of wire strikes and in-flight fires involving balloons.
Chief Commissioner John Marshall QC and investigator-in-charge Ian McClelland will tomorrow speak at a press conference on the findings.
Commission inquiries can determine causes and make recommendations to improve transport safety.
The crash was the deadliest involving a New Zealand aircraft since the 1979 crash of Air New Zealand Flight 901 into Mount Erebus, and was the third-worst hot-air balloon tragedy on record.