N610RLDassault-Breguet MYSTERE FALCON 900 · 1988

On April 16, 2015, about 1910 eastern daylight time, a Dassault-Breguet, Mystere Falcon 900B, N610RL, owned and operated by RLB Holdings Transportation LLC., received minor damage from an inflight electrical fire. The airplane had departed Westchester County Airport (HPN), White Plains, New York about 1715, destined for the Orlando International Airport (MCO), Orlando, Florida. The pilot, copilot, cabin attendant, and 12 passengers were not injured. The corporate flight was being operated under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91.

According to the cabin attendant, she noticed "a weird smell" in the galley area and started checking the appliances. She could find nothing wrong with them and asked the pilots if they had any idea where the smell was coming from. She turned around and opened the area in the galley that they kept the glasses (crystal) in and noticed "a glow behind it." The pilot then came back to assist her. He grabbed a fire extinguisher, discharged it completely, and then asked her for another one. She handed him the second one and he was able to put out the fire. The pilot then told her to watch the area.

According to the pilot, they noticed the strange odor when they were on the Standard Terminal Arrival Route (STAR) for MCO descending through 20,000 feet above mean sea level. They checked that all the ovens, microwaves, and warmers were in the "off" position. All were found to be "off", but the smell continued and then smoke appeared. The crew declared an emergency and asked for priority to the nearest airport. The pilot then "gave the flight controls" to the copilot who took over flying and the radio duties (the autopilot was on and engaged). The copilot then turned off the power to the cabin and to the galley. The pilot then used a fire extinguisher to extinguish fire. The fire was suppressed by getting behind the crystal storage and spraying the area with a Halon portable fire bottle. The crew decided to continue to Orlando as it had large runways with excellent fire and rescue capabilities. The landing was normal. The crew evacuated the passengers and fire personnel double checked the airplane for any signs of continued fire or hot spots. None were found.

According to the copilot, they noticed a smell at first and then smoke from somewhere in the airplane when they were on the STAR for MCO at approximately 1910. They determined that it was coming from the galley area, declared an emergency, and asked for vectors to the nearest airport. After the sight of smoke, and the cabin attendant assuring that everything was powered off, the pilot "gave the controls" to him. The pilot then went back into the cabin to assist the flight attendant by spraying the galley area with a halon fire extinguisher. No more smoking was observed so they decided to continue to MCO for an "abnormal approach and landing" with priority from air traffic control. After landing they could see signs of burnt wiring behind the galley.

Pilot

According to Federal Aviation Administration (FAA) and pilot records, the pilot held an airline transport pilot certificate with a rating for airplane multi-engine land and airplane single-engine land. Commercial privileges for airplane single-engine sea, rotorcraft-helicopter, and instrument helicopter. He also held a flight instructor certificate with ratings for airplane single and multi-engine, rotorcraft-helicopter, and instrument airplane and helicopter, as well as type ratings for the BAE-125, BE-400, CE-750, DA-50, G-1159, IA-JET, LR-JET, and MU-300.

His most recent FAA first-class medical certificate was issued on November 18, 2014. He reported that he had accrued 6,200 total hours of flight experience, 500 of which was in the incident airplane make and model.

Copilot

According to FAA and pilot records, the copilot held an airline transport pilot certificate with ratings for airplane single-engine land, and airplane multi-engine land. Commercial privileges for airplane single-engine sea. He also held a flight instructor certificate with ratings for airplane single engine, and instrument airplane, as well as type ratings for the BE-300, and DA-50.

His most recent FAA first-class medical certificate was issued on September 9, 2014. He reported that he had accrued 5,200 total hours of flight experience, 180 of which was in the incident airplane make and model.

Cabin Attendant

At the time of the accident, the cabin attendant had been serving as a crew member on the Falcon 900 for 3 years. Her most recent recurrent training had occurred in the Fall of 2014, at Flight Safety International's Teterboro Learning Center where she had attended the Corporate Cabin Attendant and General Emergency Training Course for corporate and general aviation aircraft. The course met the minimum recommendations for International Civil Aviation Organization (ICAO) and International Standard for Business Aircraft Operations (IS-BAO) certification, as well as many of the regulatory requirements for 14 CFR Part 135.331.

The incident airplane was a long-range, swept wing, executive jet of conventional metal construction designed to accommodate up to 19 passengers. It was equipped with retractable landing gear and was powered by three Garrett TFE 731-5BR-1C geared turbofan engines, each producing 4,750 pounds of takeoff thrust.

The fuselage consisted of the nose cone, the cockpit, the passenger cabin, the rear lavatory, the baggage compartment, the rear compartment, the auxiliary power unit and the No. 2 engine compartment (with its thrust reverser).

The cockpit, passenger cabin, and baggage compartment were pressurized. The baggage compartment was accessible in flight.

According to FAA and maintenance records, the airplane was manufactured in 1988 in Merignac, France by Dassault Aviation SA. It was then ferried in "green" condition to Dassault Falcon Jet's Little Rock, Arkansas completion center where the passenger oxygen system was installed under an FAA supplemental type certificate (STC) and Dassault Falcon Jet routing instructions. Additional avionics, and the interior was also installed, and the exterior was painted. It was completed in 1989. The airplane's most recent continuous airworthiness inspection was completed on April 13, 2015. At the time of the incident; the airplane had accrued approximately 9,949 total hours of operation.

During the 26 intervening years between the completion of the airplane at Dassault Falcon Jet's completion center and the incident, multiple C Checks (which are performed every 3,750 flight cycles or 72 months) had occurred, which required portions of the airplane's interior to be removed. During this same time period, numerous modifications had been made to the airplane by several maintenance, repair, and overhaul (MRO) organizations including multiple lighting, interior, and galley modifications, which required rerouting and re-securing of wiring, as well as removal and replacement of interior panels, partitions, and cabinetry, in the vicinity of the area of the fire.

The recorded weather at MCO, at 1853, included: wind 040°at 11 knots, 7 miles visibility, scattered clouds at 6,000 feet, broken clouds at 8,000 feet, temperature 23° C, dew point 22° C, and an altimeter setting of 30.08 inches of mercury.

The incident airplane was a long-range, swept wing, executive jet of conventional metal construction designed to accommodate up to 19 passengers. It was equipped with retractable landing gear and was powered by three Garrett TFE 731-5BR-1C geared turbofan engines, each producing 4,750 pounds of takeoff thrust.

The fuselage consisted of the nose cone, the cockpit, the passenger cabin, the rear lavatory, the baggage compartment, the rear compartment, the auxiliary power unit and the No. 2 engine compartment (with its thrust reverser).

The cockpit, passenger cabin, and baggage compartment were pressurized. The baggage compartment was accessible in flight.

According to FAA and maintenance records, the airplane was manufactured in 1988 in Merignac, France by Dassault Aviation SA. It was then ferried in "green" condition to Dassault Falcon Jet's Little Rock, Arkansas completion center where the passenger oxygen system was installed under an FAA supplemental type certificate (STC) and Dassault Falcon Jet routing instructions. Additional avionics, and the interior was also installed, and the exterior was painted. It was completed in 1989. The airplane's most recent continuous airworthiness inspection was completed on April 13, 2015. At the time of the incident; the airplane had accrued approximately 9,949 total hours of operation.

During the 26 intervening years between the completion of the airplane at Dassault Falcon Jet's completion center and the incident, multiple C Checks (which are performed every 3,750 flight cycles or 72 months) had occurred, which required portions of the airplane's interior to be removed. During this same time period, numerous modifications had been made to the airplane by several maintenance, repair, and overhaul (MRO) organizations including multiple lighting, interior, and galley modifications, which required rerouting and re-securing of wiring, as well as removal and replacement of interior panels, partitions, and cabinetry, in the vicinity of the area of the fire.

Examination of the area behind the crystal storage area of the galley by maintenance personnel from J & M Aircraft Services and Duncan Aviation, revealed the presence of sooting, and the remains of a burnt wiring bundle behind the plenum ducting.

Further examination by Duncan Aviation personnel revealed that the plenum ducting had no edge protection strip (caterpillar strip) or anti-chafe material installed on the sharp edge of the plenum ducting, the burnt wiring bundle contained the 28-volt direct current wiring and ground wires for the EMTEQ LED cabin headliner and downwash lighting, and that the associated circuit breaker in the cockpit (28VDC Bus A1 "FWD Cabin Ceiling A"), had been tripped. They also observed that two of the insulation bags had been fire damaged, the wires had been routed over them instead of directly next to the airplane's structure, and that they had been in contact with, or in close proximity to, a soft oxygen line which had been completely burned through.

In order to improve safety, the participants in the investigation took the follow actions:

Duncan Aviation:

- On April 21, 2015, Duncan Aviation filed a Service Difficulty Report (SDR) with the FAA to disseminate and alert the aviation community of the event.

- On January 19, 2016, Duncan Aviation published Service Alert 2015.12.1, titled: Inflight Fire, advising inspectors at all of their facilities to inspect for chaffing/pinching of wire, and degradation of existing wire. To inspect for proper clearance between wire routing and all aircraft articles, and that Varglass sleeve, spiral wrap, caterpillar strip, etc., could provide additional protection to wire insulation. Additionally, to use relevant devices (mirror, endoscope, etc.) to inspect inaccessible areas.

Dassault Aviation:

- On April 22, 2015 Dassault Aviation published a TOME III Event Report, to analyze the technical events that had occurred that could affect the safety of the airplane, and disseminated the information to the European Aviation Safety Agency (EASA), Direction générale de l'aviation Civile (DGAC), Organisme pour la Sécurité de l'Aviation Civile (OSAC), Bureau d'Enquetes et d'Analyse pour la Sécurité de l'Aviation Civile (BEA), and the Federal Aviation Administration (FAA).

- On November 25, 2015, Dassault Falcon Customer Service Published Falcon Service News Flash FSN-211-R00-A, titled: Inflight Electrical Fire. This was an immediate-action publication which notified operators and Dassault authorized service centers that urgent action was required, and described the event, with recommendations and electrical standard practices, along with links to the relevant procedures in the maintenance documentation.

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Oxygen System

Examination of the oxygen system revealed that the burned soft oxygen line was part of the supply system for passenger and third crew member (cabin attendant) masks.

The oxygen system used gaseous oxygen stored in a high-pressure cylinder to provide passengers and crew members with low pressure oxygen when necessary.

There were three separate systems:

- The crew distribution system which included two plug-in connectors for pilot and copilot masks.

- The supply system for passenger and third crew member masks.

- The first aid system which included two plug-in connectors in the passenger cabin.

All three systems were supplied by a high-pressure oxygen cylinder which was located under the left side of the airplane's floor, aft of the passenger door.

The passenger oxygen system included:

- An oxygen controller.

- A passenger distribution system which provided oxygen to the passenger masks, to the first aid, and third crew member (cabin attendant) mask.

The oxygen controller operated in two modes and its indicators and controls were located on its front panel. It was installed on the copilot console and would ensure automatic or manual activation of the passenger oxygen system and shutting-off of the passenger oxygen system.

The controller was supplied under a pressure of 70 pounds per square inch (psi). At low altitudes it would deliver oxygen under 19 psi, and at high altitudes under 70 psi. The boundary altitude between the two modes was 18,000 feet.

The front panel included a four-position rotary type selector, a test socket, a pneumatic indicator, and a high-pressure gauge. The four-positions of the selector corresponded to the following functions:

- "NORMAL": The normal inflight position. Automatic oxygen flow was available in case of depressurization (mask boxes would open, and oxygen masks would be supplied with oxygen during the remainder of the flight).

- "FIRST AID": Oxygen flow would be available for the first aid masks. Automatic function was retained. And it could also be used to supply passenger masks under 19 psi after the "OVERRIDE" position had been used.

- "OVERRIDE": In the event of automatic system malfunction, this position would ensure mask box opening and high-pressure oxygen supply to the passenger masks.

- "CLOSED": The passenger system supply was shut off, and the oxygen cylinder would supply only the crew system.

Mask boxes were provided above each passenger seat, in the lavatory, and above the cabin attendant jump seat. Each box was equipped with a dual pressure-operated latch, and internal door which would maintain the mask in the stowed position, and a cover held by a magnet. The masks were connected to the boxes by a cord ended by a pin which would actuate a small valve incorporated in the latch. Rated operating pressure of the latch was between 29 and 58 psi and if the latch failed to operate automatically, the passenger masks could be released by pulling open the cover of the box.

In automatic operation, when oxygen pressure on the latch built up to 70 psi, the latch piston would push the box cover open and release the internal door. An elastic strap in the bottom of the box would push the mask out of the box and cause it to fall and hang in view of the passenger at the end of its cord. Pulling on the mask would then cause the valve to open and oxygen to flow. The mask would be held over the face by an elastic strap passed behind the head. In case of an automatic system failure, or to deploy the masks manually, the oxygen controller selector could be set to "OVERRIDE" which would allow the masks to fall out and be supplied with oxygen.

Emergency Procedures

Review of the Falcon 900 Operating Manual and Airplane Flight Manual, revealed that the airplane manufacturer had provided guidance in the manuals on how to operate the oxygen system for depressurization, air conditioning smoke, electrical smoke or fire, smoke and unusual odors removal, and failure of the passenger masks to automatically deploy.

Review of these procedures indicated that if the crew had followed any of the above procedures, the soft oxygen line which had burned through during the fire, would have been pressurized with oxygen by the automatic system or manually pressurized when "OVERIDE", was selected.

Oxygen Line and Wiring Installation

Examination of photographs of the oxygen line and wiring in the area of the fire damage indicated that sometime in the past, it had been changed from the originally specified configuration, as it did not appear to conform to Dassault Falcon Jet's Cabin Oxygen System Drawing F90-42002, nor did it appear to comply with Dassault Falcon Jet's Installation Standard FES 105, that was in effect at the time of the initial airplane completion at Dassault Falcon Jet's completion center.

Further examination of the photographs also revealed that:

- The clamp installed on the oxygen line near the fire damaged area appeared to be the wrong part number clamp, as it included in the clamp assembly a white silicone pad instead of the specified black chloroprene cushion.

- A spacer appeared to be missing, which was required under the clamp near the fire damaged area to achieve a minimum ½ - inch separation per STC drawing F90-42002 between the oxygen line and the covered wiring harness immediately to the right of the clamp.

- A support also appeared to be missing, which was used to maintain the minimum ½-inch separation per STC drawing F90-42002 at the point where the oxygen line crossed the burned wiring bundle.

Materials Laboratory Examination

15 sections of the cabin lighting wiring, and the fire damaged soft oxygen line were submitted to the NTSB Materials Laboratory for examination. Nine sections of the wiring had sustained fire damage of varying degrees. The remaining six lengths of wiring exhibited mechanical damage on the ends that were consistent with cutting.

For the fire damaged sections, five sections had fire damage in the middle of the section. Three of these sections had only surface charring damage to the insulation and the damage did not extend down to the conductor. For the remaining sections, the conductor was exposed.

For wire section 10LZ1-3-2LZ1-FLW, the fire damage (charring, melting, missing insulation and thermal discoloration) was limited to the wire insulation. The exposed conductors underneath were intact.

Wire section M22579/18 also exhibited similar insulation damage in the middle of the section. The conductors in the area exhibited thermal related thinning and melting and fusing of the individual conductors. The remaining sections had melting and some small areas consistent with electrical erosion, which is is the loss of material due to sparking or arcing and indicated that material transfer may have occurred when one conductive, electrified material had come in to contact with another conductive material.

Of the remaining four damaged wire sections, the damage was limited to one end on each section:

- On wire section 10LZ16-GND-C, there was one area that resembled electrical beading which was indicated by round copper globules with clear lines of demarcation found on the ends of the damaged electrical wire conductors, and which indicated that the conductors were subject to thermal exposure.

- On wire section M81381/22-16- 28427-1LZ3-A1-1DLZ, there was an area of damage consistent with electrical erosion.

- The two remaining wire sections with end damage displayed generally smooth melting on the ends. Despite the damage to these wires, there was no clear indication of chaffing, rubbing, nicks or damage that may have led to an arcing event.

The soft oxygen line sustained extensive damage mid length of the hose. The soft hose material was missing, leaving only the support coil present. The remaining soft hose material was charred and ridged on the ends were the material was still present. The support coil did not appear to have any damage other than some thermal discoloration. The surface of the exposed support coil was examined using scanning electron microscopy and energy dispersive spectroscopy to look for evidence of copper transfer consistent with arcing wiring against the support coil. No evidence of copper on the exposed coil was found.

Post Incident Airplane Examinations

Post incident, Dassault and Duncan Aviation conducted examinations in the area of the fire on airplane's that were brought in for maintenance. During the examinations they discovered the following:

- On three airplanes, the layout was acceptable.

- On a 4th airplane, interference was observed between the oxygen line and the gasper line, but not with the electrical bundle.

- On a 5th airplane, interference was observed between the oxygen line. and the structure, the gasper lines and pressurization valve vacuum lines, a small electrical bundle, and Frame No. 5.

- On a 6th airplane, a wire displayed damaged insulation.

- On a 7th airplane, a section of wiring was pinched.

NTSB Database

Review of the NTSB database revealed two other previous incidents involving electrical fires in Dassault airplanes:

NTSB case number FTW88IA052: On January 21, 1988, at 1520 central standard time, a Dassault-Breguet DA-10, N79PB, received minor damage from an in-flight fire after departure from Dallas Love Field Airport (DAL), Dallas, Texas. The flight crew and three passengers were not injured. Day visual meteorological conditions prevailed, and an instrument flight rules flight plan was filed, for the flight destined for William P. Hobby Airport (HOU), Houston, Texas. the Westchester County Airport (HPN), White Plains, New York. The business flight was conducted under 14 CFR Part 91.

The flight experienced an in-flight fire resulting from an electrical short in an auxiliary circuit breaker panel that was installed after the airplane was manufactured. The short resulted from the use of a mounting bracket that chafed against the input wires. The flight crew extinguished the fire but failed to complete the prescribed emergency procedures to isolate the faulty circuits and restore power to other circuits. This resulted in a landing without stabilizer trim, wing flap deployment, or brake anti-skid protection. The pilot intentionally swerved the airplane off the runway pavement to avoid overshooting the 8,800-foot-long runway.

NTSB case number NYC04IA037: On November 18, 2003, at 1700 eastern standard time, a Dassault Falcon 50, N14CG, received minor damage during an in-flight fire during climb out from the Bradley International Airport (BDL), Windsor Locks, Connecticut. The two certificated airline transport pilots, and three passengers were not injured. Night visual meteorological conditions prevailed, and an instrument flight rules flight plan was filed, for the flight which was destined for the Westchester County Airport (HPN), White Plains, New York. The company training flight was conducted under 14 CFR Part 91.

Shortly after takeoff, at 500-600 feet AGL, the flight crew noticed smoke in the cabin, declared an emergency, and returned to land without incident. After landing, crash fire rescue extinguished a fire in the overhead paneling of a coat closet, which was located directly behind the cockpit. Examination of the airplane revealed extensive heat damage to the overhead paneling around a closet light fixture in the aircraft cabin. Visual examination of the damaged area revealed that electrical wiring and an oxygen line were installed in close proximity to each other in the area of the light fixture. Additionally, examination of the oxygen line revealed a pin-size hole through the circumference of the line with signatures consistent of electrical arcing. Further examination of the light fixture revealed areas of severe localized heating and melting. Examination of maintenance records revealed two entries in the past 12 months, which described the closet light circuit breaker popping during illumination of the light. This occurred as a result of an electrical arcing between the light assembly and an oxygen line. Both instances included installing Teflon tape to protect interference between the assembly and the oxygen line.

The National Transportation Safety Board determined the probable cause of this incident to be: An in-flight fire, originating from electrical arcing, which subsequently created a hole in an oxygen line.

During post incident examinations of 72 other airplanes, only one additional Falcon 50 was identified as needing a clamp to improve the oxygen line attachment. No interference between wiring and oxygen lines was noted in any of the other Falcon 50 airplanes.

As a result of this incident, Dassault Falcon issued a Falcon Operator Communique – Urgent – No. 031203, and Falcon Service News Flash FSN50-50EX-113 to all Falcon 50 operators, which recommended that the airplanes be inspected for any indication of interference between the closet light fixture or its wiring and the surrounding structure or equipment, particularly oxygen lines.

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