Dear Hughes500,
Your chagrin is understandable given the misinformation in the industry regarding Halon.
My company is a major supplier of aviation fire extinguishers, and I had the opportunity to attend a meeting with the FAA at their Atlantic City fire test facility. Also attending were representatives from major airlines, aircraft manufacturers, the US military and international regulatory bodies, including EASA.
While there, a Halon fire extinguisher was tested and compared to a similarly rated sodium bicarbonate dry chemical fire extinguisher to determine whether a dry chem. extinguisher could be safely used in place of a Halon extinguisher. A key test was the "hidden fire test," which tests the ability of an extinguishing agent to extinguish hard to get at fires behind panels, etc. The Halon extinguisher performed phenomenally, the dry chem. extinguisher failed.
I understand that your argument concerns toxicity. In the nearly 30 years that Halon has been used in aviation, there has not been a single confirmed case of a pilot or passenger being incapacitated by Halon. To fight the perception that "Halon will kill you," the FAA, following a recommendation by the NTSB, in 2004 published AC120-80 on In-flight fires. The FAA also just released a video on the same topic. The message: Don't hesitate to use a Halon fire extinguisher on aircraft - the combustion products of the fire are much more toxic. Both the AC and video can be found on the FAA's website -
www.faa.gov.
As for discharging a dry chemical fire extinguisher in a confined space, it is not advisable. At the FAA test, we discharged a dry chemical extinguisher in the interior of a 737. The cloud of blinding, choking powder would be have been debilitating in the much smaller confines of a helicopter.
The consensus of the group after these tests was that purely from a safety standpoint, dry chemical fire extinguishers should not be used on aircraft. Many also voiced concern that the corrosive nature of dry chemical extinguishers is another very good reason to avoid their use.
Regards,
Chris Dieter
H3R Aviation, Inc.