An Analysis of What Caused VALUJET 592 To Crash

From: Ed Block EdWBlock@aol.com\line.

Date: 11 Jun 1998\line.

Time: 21:57:04\line Remote Name:

From: Edw Block <EdwBIock@aol.com

Subject: Valujet 592 Date: Thursday, November 06, 1997 1:49 PM


My name is Edward B. Block, and I am a former Department of Defense wire and cable specialist. I was the government's liaison to all the related Industry Technical Committees for aircraft wire and cable, and recognized as the top expert in wire and cable at the Department of Defense's Industrial Supply Center from 1974 - 1984. In this capacity, I was recognized by; The Society of Automotive Engineers, Chairman of the Aerospace Electrical and Electronic Equipment Committee, The Aviation Safety Institute, The National Electrical Manufacturers High Temperature Insulated Wire Committee, and The Department of Defenses Electronic Supply Center, as well as being named as the most Outstanding Personnel of the Year in 1981 for the entire Supply Center.

I had been awarded this honor for saving millions of dollars through the Valve Engineering Beneficial Suggestion Programs by solving complex legal / logistics problems that had in some instances plagued the government for over seventeen years. In addition I have been published in The Department of Defenses Dimensions Magazine and endorsed for a White House Fellowship position by my Congressional Representative, and submitted testimony to Congressional Committee Hearings. I have briefed The Federal Aviation Administration, The Federal Bureau of Investigation, The General Accounting Office [National Security and Transportation Departments], The Department of Transportation Inspector General, The Navy Department, Congressional Representatives, The National

Transportation Safety Board, The White House Commission on Aircraft Safety and Security, The National Defense Universities Industrial College of the Armed Forces, The Joint Logistics Commanders Ad Hoc Group on Aircraft Wiring on wiring problems.

I have also been featured on ABC's Primetime Live, Fox News Network, KIRO - TV interviews and the subject of news paper articles nationwide including a radio interview which included a debate with Senator Roth of Delaware.

I have read the National Transportation Safety Board's, Office of Research and Engineering's Fire and Explosion Group, Factual Report dated March 4, 1997 as well as the Systems Group Chairman's Factual Report dated June 12, 1997 and I must take exception to their conclusions. My review of this accident must begin with the issuance of the FAA's Airworthiness Directive 96-07-15 effecting the VALUJET flight 592 Aircraft on May 16, 1996, five days after the crash. Per the amendment to part 39, it addressed what was referred to as an "unsafe condition" issued "To prevent the potential for fire and uncontrolled smoke throughout the cockpit due to damaged electrical wiring". [Emphasis added].

It is worth noting that not until 12 February 1997, when the White House Commission on Aircraft Safety and Security issued its final recommendations, did this serious issue of safety and degraded wire get noticed. Recommendation 1.9 states; the Commission is concerned that existing procedures, directive, qualify assurance and inspections, may not be sufficient to prevent safety-related problems, caused by the corrosive and deteriorating effects of non-structural components of commercial aircraft as they age.

Non-structural components include electrical wiring, connectors, wiring harnesses, and cables. In response to the Commission recommendation the FAA has finally acknowledged the launching of its first study of aging wiring [Newsday 13 July 1997] in addition, NASA will spend $500 million to now study aging systems.

These actions certainly are reactive, rather than proactive. When you consider as early as 8 November 1993, the Senate hearing before the Subcommittee on Aviation, Thomas McSweeny concluded after referring to 264 cases of smoke fumes or fire, in or near the cockpit, over just a 6 year period, that "existing procedures are satisfactory". Even though the FAA's own service difficulty reports (SDR’s) from 1974 - 1994, indicate a total of 2,039 wire -related problems. Mr. McSweeny said in a 21 May 1997 letter to Congressman Jones Greenwood [R. Pa.], that he felt there still were no problems with aircraft wiring, but that the FAA's upcoming study would consider the issues I raised at the 10 April meeting.

The military knew as far back as 1982, the far reaching effects of aircraft wiring that had degraded by requesting $360 million in FY83 to remove wire insulation that had an abnormal aging, hardness and cracking problem, resulting in wire-to-wire shorts, spurious signals on control wires causing spoilers to stick in the up position, inadvertent auto-pilot commands and power shorts which disable the auto-pilot completely. [Appropriation APN-Activity 5, F-14A]. There have been 144 F-14 crashes, to date, out of 600 produced.

In March 1995 the FAA's own Technical Center in Atlantic City, NJ., issued a report on electrical short-circuit and current overload tests performed on commercial aircraft wiring. [FAA Technical Center Report, 5 March 1995, page 1, paragraph 1. 1.] Based on just 3 illustrations of aircraft fires, certain questions have presented themselves including whether there is anything definitive an investigator can look for to help determine if electrical failure was the cause [FAA Report, page 2 paragraph 1.2c].

Their conclusion: "no visible differences were detected in comparing wires subjected to over-current with those subjected to the fire". By flexing the cables it was found that the wires that were subjected to the fire were more brittle than those exposed to the over-current [FAA Report 3/95, page 4, paragraph 2.2, last sentence]

This background is useful in order to elaborate on the contradictory findings in comparing both reports. The Fire and Explosion Group Factual Report states on page 2 section d [Details of Investigation] that, "no soot or fire damage was observed on recovered components from the cockpit or the electric and electronics department." Whereas, on page II, paragraph 8.0, Electrical, 2nd paragraph it states, "There were numerous places that the wires within each wire bundle were broken". The broken places showed up as very short blackened areas on each of the breaks on an otherwise white insulation. These blackened areas were visible the entire length of the bundles that included areas where the conduit was heavily sooted and heat damaged and in areas where there was no soot or heat damage.

The description cited above is repeatedly discounted with the phrase "no signs of soot or heat damage" associated with every reference. However in paragraph 8.5 [left tunnel wiring] there is an obvious shift in terms. There is at this point an acknowledgment that some wiring was actually in a fire. The remainder of conduit HWG toward the floor beam was consumed. The wires in HWG in the areas where the conduit was consumed by fire had fire and heat damaged insulation with areas of missing insulation. The conductors were heat damaged, but were not severely hardened, [FAA Report 3/95, page 4, paragraph 2.2 last paragraph last sentence]. The reason this is significant is that this is only the first of 12 separate references to this finding. Although some references cite no severe embrittlement, it appears some disconcertment was utilized in these findings. According to the findings, the FAA report would conclude that they were the result of over-current since they were less brittle. This is based on the assumption they were flexed versus just visibly bent. The question is: are these overused catch phrases meant to negate electrical malfunction as a possible cause of the fire?

The fact that there was no mention of what type of insulation was used in this aircraft throughout this report seems compelling. Was it known to be flammable or to produce large volumes of smoke? In fact it was identified, if not by type of characteristic in the afore-mentioned Airworthiness Directive 96-07-15 issued "to prevent the potential for fire and uncontrolled smoke throughout the cockpit due to damaged electrical wiring".

So it has been established, that there was a known hazard in the cockpit. A potential for fire, and this is an understatement, is that the wire insulation used is MIL-W-5086/2, An extruded polyvinylchloride material [PVC] that was banned by the Military in MIL-W-5088 [the Aerospace Vehicle Wiring Specification] in 1980. Its flammability was unmatched, in that the flame test requirement, had to be done horizontally, to slow the flame to an acceptable level. If the wire were elevated to 60 degrees it would fail to pass. The smoke density, was also never equaled by any other wire insulation material tested to date. There is also no reference in the report of the transcript from the CVR where pilot states at 1410:15 "we've got some electrical problem." Followed by the co-pilot agreeing and then at 1410:20, 5 seconds later, "we're losing everything"!

These reports are significant for what is not included. There appears to be a conscious effort to dissuade even the consideration of electrical wiring as a potential for fire. Even though the pilots acknowledged their problem: the aircraft had a history of electrical problems, the aircraft type was identified as being in an unsafe condition due to damaged electrical wiring, and electrical wiring is now under study by the FAA after chasing the ignition source on TWA 800, there is no mention in these reports. Perhaps the statement "other than in areas of heat and smoke damage, no evidence was found of pre-impact failures in any aircraft systems. System Group, Page 2, 3rd paragraph is a stretch. It's like saying there was no evidence of a person’s stroke prior to it. I view it as a disclaimer. Maybe the reference to the "decontamination" that ensued after retrieval didn't involve any chemicals or process that might have removed evidence. [Systems Group Report, Page 3, section d, paragraph 2] it is not explained. If there was a comparative analysis done to the hardness levels of conductors, other than by subjective flexing, it should be so stated.

Somehow, this preponderance of evidence must all be overlooked, to then make a leap of faith, to conclude an oxygen generator was to blame. Although it couldn't be recreated without pulling pins, and is admittedly not possible to recreate, it was somehow duplicated in a cargo hold with 5X the volume, with the cargo door open for filming purposes. Based on the above, I feel electrical wiring was the most probable ignition source, and the oxygen generators only contributed to the fire.

Ed Block




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