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We help Organizations quickly Conceptualize, Design, Develop, and Implement Innovative Cost-Effective Solutions for Avionics, Aircraft, and Flight Guidance-Navigation-Control Systems. |
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Home
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What
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Summarized below are some of our Learjet-specific
accomplishments. In addition to telling you about what we
have done, we will also show you-- in detail. These
accomplishments in combination with the "What We Know" page
should give you a good idea of what ASTECH can really do--
for you. |
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Situation: The Mach/Overspeed Warning Switch used on older Learjet aircraft (Learjet 23, 24, 25, 28, 29, 35, 36, 55, & C-21) has a high failure rate (Low MTBF/MTBUR). One Operator commented: "... our aircraft cannot pass a service facility without changing out the mach switch..." Across the Learjet fleet, there are over 25 different Mach Switch Part Numbers in use, each with different Mach/ Airspeed/ Altitude setpoints-- a spares nightmare. There are roughly 2500 Mach Switches in use on roughly 1400 Learjet aircraft. Because of the high cost of Mach Switch Overhaul/ Replacement and associated Removal/ Replace/ FT Labor costs, Operators have identifed this as a top priority problem that must be fixed (Learjet Advisory Panel Top 10 Item).  Solution: We conceptualized, designed, and wrote the specifications for a Fleet-Common Mach/ Overspeed Warning Unit with the following attributes:
Status: Based on feedback we have been getting,
operators want this Fleet-Common Mach/Overspeed Warning
Unit. But after 9-11, development on the Fleet-Common
Mach/Overspeed Warning Unit was terminated due to funding
cuts. We are currently looking at resurrecting this effort--
if enough interest exist. If the Fleet-Common Mach/Overspeed
Warning Unit is of interest to you, please give us a
call. |
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Situation: RVSM is coming to domestic US airspace and could be operational by December 2004, according to the FAA. RVSM has already been imlemented in Europe, Canada, and oceanic airspace in the North Atlantic and Pacific. RVSM will decrease the separation minimums from 2000 ft to 1000 ft between suitably equipped aircraft flying between 29000 and 41000 ft (FL290 to FL410). Aircraft not FAA certified for RVSM must either fly below FL290 or above FL410, which can result in higher fuel consumption and longer flight durations. At this time, there are no FAA certified RVSM solutions for Learjet 20 Series aircraft. Learjet-Bombardier has chosen not to offer a solution for the roughly 580 20 Series aircraft. A few other companies are currently working on RVSM solutions for 20 Series Learjets. Our preliminary analysis on 20 Series aircraft along with our RVSM experience on other Learjet aircraft indicates that "typical" RVSM solutions will not enable the aircraft to meet RVSM performance requirements. Simple tweaks can be performed, but this still will not fix the RVSM performance problems. Solution: As a result of studies performed for the FAA (see below), we have gained extensive experience on 20 Series Learjet Avionics, Autopilots (JET FC-110), & Flight Control Systems. We also understand the similarities and differences between aircraft models in terms of coming up with a fleet common solution (which could also be adapted to other airframes). More importantly, we know what it takes to make an RVMS solution easily meet performance requirements-- even with the existing AFCS. And with us on your team, we can help you capture the entire RVSM market on 20 Series Learjets-- while your competition continues to struggle with their RVSM performance problems.  Status: If you have an interest in capturing the
entire RVSM market on 20 Series Learjets, let us help you
make it happen. |
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Situation: As you Learjet Operators know, maintenance manual procedures can sometimes seem excessive. On many systems, the entire system(s) has to be completely functional tested whenever any component in the system is removed and replaced. For some components, all this testing may be necessary because the component is the principal element in the system & interfaces with all the other components in the system. For many other components, all this testing is not necessary-- only the interfaces to/from the component and the functionality that the component provides to the system need to be functional tested. And during Functional Testing, reperforming extensive component Acceptance Testing which has already been performed by the Vendor should be minimized. Eliminating this unnecessay &/or redundant functional testing can save operators considerable time and money on maintenance. Learjet-Bombardier recognized this as a potential cost savings to operators and implemented the RTS initiative for in-production aircraft (M31A, M45, M60). The objective of RTS was to write streamlined functional test procedures that were optimized for each component that could be removed/replaced in the system. Solution: We were directly responsible for RTS Test Procedures on systems in Chapters 22 (Autopilot), 27 (Flight Controls), 31 (Indicating & Recording), 32 (Landing Gear), & 34 (Navigation):
We supported RTS Test Procedure development, research, &/or review on:
We helped establish the RTS methodology at Learjet by creating the formats, guidelines, & templates that all RTS procedures would use (as well as review most of the electrical/avionic RTS procedures that were generated). Each system that we generated RTS procedures for was extensively researched (Learjet design/ test/ maintenance/ safety documentation, vendor documentation, Technican/ Vendor discussions, lessons learned, undocumented tips, shortcuts, ....) so that we completely understood the system from all perspectives and at all levels (hardware/software, system-subsystem-component level, operationally, ...). We worked closely with Learjet Customer Service, Production, & Core Engineering, and with Equipment Vendors to ensure that the RTS procedures were correct, optimized, and tested out. We also worked closely with Learjet Tech Pubs to ensure that the RTS procedures made it into the maintenance manuals correctly-- this is much harder than it sounds. We also took the initiative to update Production Test Procedures to RTS standards, which was outside of the effort scope-- needless to say, production was very happy. We took the RTS concept much farther than was ever intended. Test procedure steps are usually written in standard form (do this, then do this, then do this, etc), but this form gives little insight into problem isolation when procedure steps don't test out. In addition to significantly streamlining the Function Test procedures, we added diagnostics/ troubleshooting logic that identifies exactly what to check if a procedure step doesn't test out (Example: do test step [IF this test step fails ==> check On-Side MAN Roll Trim RWD wiring, Trim Engage & AP Dump Wiring], do next test step [IF this test step fails ==> check MSW wiring & PRI Pitch Trim], etc). We also added detailed functional block diagrams that detail all system components, interfaces, & interconnects, and are designed to be used in conjunction with the RTS procedures to help diagnose/ troubleshoot systems. Technicans can now get up to speed on an RTS'ed system in no time and know exactly where to start looking when problems occur-- no more stumbling thru a complex/unfamiliar system for hours/days trying to find & fix a problem. And with Technicans needing to be proficient on more & more complex electrical/ avionic systems across more & more aircraft, it gets more difficult for them to remain an expert on a specific system on a specific aircraft. As a result, our objective has been to create RTS procedures that makes any Technican an expert at quickly testing, troubleshooting, & fixing a system. For the operator, this helps minimize maintenance costs and AOG durations. Have we been successful? You be the judge. The M31 AHRS FT was reduced from a 4+ hour test to less than 1 hour, plus the speciality test equipment was eliminated-- which makes it much easier to FT a removed/replaced AHRS at any remote location without having to wait for the speciality test equipment to arrive (this does happen more than you think). The M31 Flight Control System FT used to take production 8+ manhours to run (if everything went smoothly), now it takes less than 1 hour worst-case. If test steps failed, hours/days may be needed to troubleshoot & fix the system, afterwhich the FT would need to be rerun. Production came up with the idea of enlarging (poster size) & laminating the RTS functional block diagrams & using marker pens to trace wire runs during troubleshooting. Used in conjunction with the aircraft wiring diagrams and RTS procedures, Production has said that they can find & fix problems in a fraction of the time it used to take. For each RTS procedure that we have generated so far, we have gotten the same type of feedback. Several of the Learjet-Bombardier training centers now use our RTS procedures and functional block diagrams, and have found them so helpful/benefical for training that they asked that we send them anything & everything that we generate. Vendors of equipment that we have RTS'ed are doing the same thing. Some of the laminated functional block diagram posters were made available at recent Maintenance & Operations (M&O) conferences-- the posters went quickly and calls came in asking for more. Status: At this time, we are not involved in any
RTS-type activities. But there is much more that could &
should be done in this area. And we can help you like we
helped Learjet. If you are looking for ways to bring down
the cost of ownership on your aircraft for operators, this
is the ticket. We are guessing that reductions similar to
what we generated for Learjet are possible for many systems
on many aircraft. Let us help you help your customers save
money. |
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For more information on how ASTECH Engineering may be able to help you, please contact Jeff Wilson at astech@cox.net or call 316-304-6157. © Copyright 2002 ASTECH Engineering. All rights reserved. No part of this document may be reproduced in any form without the expressed written consent of the author. |
Learjet
Fleet-Common Mach/Overspeed Warning Unit