From: email@example.com (Ed Hahn) Organization: The MITRE Corporation, McLean, Va. Date: 16 Feb 94 13:13:51 PST References: 1 2
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In article <airliners.1994.927@orchard.Chicago.COM> firstname.lastname@example.org (Khee Chan) writes: >Now, why would they do this? What are the pros and cons of each? For the bits that are required to generate the flashes, the following applies: Rotating beacon == mechanical == moving parts == more maintenance Strobe == electronic == no moving parts == less maintenance The difference between the type of anti-collision lights on the above mentioned 727's is probably more likely to be correlated to the vintage of the aircraft. Maybe customer preference has something to do with it - perhaps someone from Boeing can answer this. ----- Khee Chan email@example.com, firstname.lastname@example.org, jplsp::kchan <<I speak for nobody and nobody speaks for me, sometimes not even myself!>> --- I'll take a shot if you don't mind. I agree with you regarding the maintenance aspects of the two systems, first off. >From an operator's perspective, whether an airline would standardize at all, or even which to standardize would depend on the following: 1) Operator experience in component consumption (how many burned out lights/motors, etc.) on a per year basis, 2) Spares commonality with other fleets. 3) Spares which would become obsoleted. 4) Engineering manpower to write a modification order and CERTIFY it. (Could be non-trivial, depending on which region of the FAA the operator reports to). As with most operator decisions, the economics usually decides: For example, Airline X has 20 B727s, mostly delivered before strobes became an option. Airline X also has 10 B737-200s, which happen to use the same mechanical system components (I don't know for sure, I'm just creating a hypothetical case). Airline X operates mostly in the southern part of the US, without much time spent in salt environments. They also tend to fly a daylight charter schedule. Airline X's consumption of parts is rather insignificant compared with the cost of retrofit. Example 2: Airline Y has 95 B727s, about 30 of which were delivered before strobes were an option. Airline Y, which flys mostly cargo, operates a heavy night schedule between Chicago and Florida/Caribbean. After getting rid of all of its B707s, the airline only has newer aircraft like the EFIS MD83 (aside from the B727s). The yearly maintenance costs for the older system has been increasing over the last few years. Because the newer aircraft are all strobe equipped, it may make sense to retrofit these aircraft, especially since the management has decided to hush-kit these aircraft to meet Stage III noise regulations. Now I will wait for the usual bandits to pick apart the details, but you get the idea. ;-) Hope this helps, ed (ex. American Airlines/Trans World Airlines Avionics Engineering) //////// Ed Hahn | email@example.com | (703) 883-5988 \\\\\\\\ The above comment reflects the opinions of the author, and does not constitute endorsement or implied warranty by the MITRE Corporation. Really, I wouldn't kid you about a thing like this.