Security of Flight Doors Improved Through Use of MTI-2100 Fotonic Sensor - MTI Instruments - #1

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MTI Instruments, Inc. 325 Washington Avenue Extension Albany, NY 12205 PH: +1-518-218-2550 OR USA TOLL FREE: 1-800-342-2203 FX: +1-518-218-2506 sales@mtiinstruments.com www.mtiinstruments.com APPLICATION NOTE Security of Flight Doors Improved Through Use of MTI-2100 Fotonic Sensor Introduction NTSB safety records point to numerous incidents involving cockpit door locking/unlocking mechanisms, either accidentally opening/closing or not operating fast enough upon command. In the assembly and testing of these door locking mechanisms, a reliable and repeatable method was needed to determine how well the mechanism responds to instantaneous cockpit open/close commands. A key supplier to the aerospace industry who manufactures many types of solenoid door latches was faced with the requirement to measure the motion of the lock plunger. These latch assemblies, a key safety feature in fl ight deck door locking systems, must quickly and positively seal aircraft cockpit doors against unauthorized cockpit entry but also be capable of opening upon a sudden loss of cabin pressure. The Problem Since the solenoid latch needs to complete the locking or unlocking cycle in as quickly as 13 milliseconds, it was critical to accurately track the fast motion of the plunger with a measurement system having a frequency response in excess of 100,000 Hz. Because of limited access to the interior of the cockpit door plunger/solenoid assembly, a compact, rugged and fast response sensor would be needed. The Solution After a thorough analysis by MTI Instruments’ application engineers, the MTI-2100 Fotonic sensor was selected to make this measurement. The MTI-2100 transmits a beam of light through a fi ber optic bundle onto the target surface and the amplitude of the refl ected light returning back to the probe generates a very precise curve of volts vs. distance. With a response time of up to 200 kHz, there is minimal phase delay in measuring the solenoid motion and the probe is also immune to any electromagnetic interference (EMI) present in the vicinity of the latch assembly. MTII appnote: cockpitdoors.pdf - Page 1 of 2