Seeking Aircraft Electrical Power Generation and Load Management Info
Seeking Aircraft Electrical Power Generation and Load Management Info
(OP)
All,
Anybody know of a good design reference for subject topic. I'm trying to bring myself up to speed on the principles after an incident on an older airplane. I'm not seeing what I need in the aircraft maintenence guidance.
Thanks
Anybody know of a good design reference for subject topic. I'm trying to bring myself up to speed on the principles after an incident on an older airplane. I'm not seeing what I need in the aircraft maintenence guidance.
Thanks
In theory, there is no difference between theory and practice however, experience suggests that in practice, there is!
My posts reflect my personal views and are not in any way endorsed or approved by any organization I'm affiliated with.





RE: Seeking Aircraft Electrical Power Generation and Load Management Info
Or: aircraft electrical load analysis
RE: Seeking Aircraft Electrical Power Generation and Load Management Info
You could look for an ELA for a similar type of aircraft, particularly one in the same weight class, or having the same engines, etc. Reading that ELA you will find many items of equipment common to both aircraft, and even if the specific type of (for example) landing light is different on the two aircraft, you may find that the electrical load is roughly the same anyway.
STF
RE: Seeking Aircraft Electrical Power Generation and Load Management Info
TTFN
I can do absolutely anything. I'm an expert!
homework forum: //www.engineering.com/AskForum/aff/32.aspx
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers
RE: Seeking Aircraft Electrical Power Generation and Load Management Info
For example, the analysis for a 2-engine aircraft would have to include analysis of the condition when one engine has failed (meaning only one generator). Obviously the design has to account for such eventualities.
RE: Seeking Aircraft Electrical Power Generation and Load Management Info
You reference "older airplane", I've seen lots of times when alterations are done that add electrical equipment, even if the 337 indicates an electrical load analysis was performed, there is no analysis to be found. AC 43.13-1b Chapter 11 paragraph 11-35 and 11-36 cover the topic od electrical loads and controlling them. There is also an Australian AC 21-38 that goes into detail on what an ELA is and how to develop it. While it is for Australian certification, it provides a lot of good info that would be applicable to US certified aircraft. MIL-E-7016F is another good reference document for the development of an ELA.
RE: Seeking Aircraft Electrical Power Generation and Load Management Info
I'm trying to better understand load management from an operating perspective after an in flight incident.
I'm wondering if various commercial aircraft wouldn't have individual load management philosophies based on a failure effects analysis of their electrical power generation system. Certainly the ELA would play a big part too I suppose.
I'm not in the hot seat for this, just trying to understand what I watched unfold.
I've got a copy of IEEE STD 128-1976 from an internet search, but it's very dated.
In theory, there is no difference between theory and practice however, experience suggests that in practice, there is!
My posts reflect my personal views and are not in any way endorsed or approved by any organization I'm affiliated with.
RE: Seeking Aircraft Electrical Power Generation and Load Management Info
TTFN
I can do absolutely anything. I'm an expert!
homework forum: //www.engineering.com/AskForum/aff/32.aspx
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers
RE: Seeking Aircraft Electrical Power Generation and Load Management Info
such as the following guidance.
https://www.faa.gov/regulations_policies/advisory_...
Aircraft specific load shedding information is most likely held in the Flight manual (if you are lucky).
Yes can we get more information about the "incident" please
RE: Seeking Aircraft Electrical Power Generation and Load Management Info
In your original post, you referenced "older" aircraft. Depending on age, your answers may be in CAR 3, CAR 4a, Car 4b, or if old enough, Aero Bulletin 7a. You need to look at the TCDS to see what the Cert Basis of the given aircraft is to understand what the regulatory requirements were at the time of certification. Most "older" aircraft have a lot more electronic equipment installed that what was originally envisioned. If these alterations weren't well thought out, that could be the source of your issue. Keep in mind that with a few exceptions, based on 21.101 any alterations made after 2003 need to comply with the regulations in effect at the time of application for approval. So even if you have a CAR 4b airplane, the changes being incorporated after 2003 will most likely need to comply with the requirements of 14 CFR Part 25.
RE: Seeking Aircraft Electrical Power Generation and Load Management Info
I think what I may really be looking for is an explanation on how the MEL for a large multi engine commercial jet is developed.
That is, what methods are used to determine what equipment in an electrical power generation system can be inoperative or deactivated at departure?
In theory, there is no difference between theory and practice however, experience suggests that in practice, there is!
My posts reflect my personal views and are not in any way endorsed or approved by any organization I'm affiliated with.
RE: Seeking Aircraft Electrical Power Generation and Load Management Info
Had a long post for this question... but somehow managed to wipe it out [+1-hour work] with a few off-cadence key strokes or some other spastic keyboard actions. This is about the 5th time I have wiped-out long post replies by some action I cannot fathom.
That will teach me to type/edit to a word document first... then post to Eng-Tips. I'll try again tomorrow.
Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true.
o For those who believe, no proof is required; for those who cannot believe, no proof is possible.
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion"]
o Learn the rules like a pro, so you can break them like an artist. [Picasso]
RE: Seeking Aircraft Electrical Power Generation and Load Management Info
It happens to all of us, if we post often enough.
I have a habit of pressing "Ctrl-A" then "Ctrl-C" to get everything on the the clipboard before clicking either Preview or Submit. My problem is having my internet connection interrupted by a lousy ISP, but it's a good habit for any reason.
STF
RE: Seeking Aircraft Electrical Power Generation and Load Management Info
So for an electrical system, lets say you have a 2 engine aircraft with an APU. Lets say the APU has a limitation that it cant be started if the OAT is below -20. Lets continue and say this aircraft is certified for extended range, and normal cruising altitude FL320 and above. The OAT at FL320 is below the starting temp limit of the APU. Based on a safety analysis lets say that if a given bus relay fails, the only way to get power to a required system is with the APU. The MMEL may say that with some combination that may cause the relay to fail, the APU must be operating prior to feet wet or no extended range (Operating Procedures). There may be associated maintenance procedures like disconnect, cap and stow a connector, pull and collar a CB, placard the panel. Lots of other possibilities. All based on the basic safety analysis of the system using things like Fault Trees, FAMECA Analysis and all kinds of other things to show compliance with 25.1309.
Hope that helps.