View Full Version : ETOPS and nonů

9th Jun 2003, 21:24
I was wondering, what qualifies and engine/aircraft to be ETOPS, say for example the 767 compared to a non ETOPS 767.

I understand the concept of extended range/flying on one engine, but I was after what are the mechanical differences. Are these engines modified in any shape or form?

Thanks for any replies, w.

10th Jun 2003, 00:07

well they may have to meet a stricter time frame on updated service bulletins.

Basically they are tracked against their hard shutdown rate as a fleet and their maintenance is scheduled against this tracking. In some cases this might mean prioritizing an updated service bulletin on this fleet vs a quad fleet. In the long run its the operators call (he has to demonstrate to his authorities that his reliability meets ETOPs standards).

However in some cases the data may be more compelling (a high fleet failure rate of a component) and require a fleetwide restiction of ETOPS until a retrofit can take place.

12th Jun 2003, 15:52

The differences between Etops and non Etops, are based in maintenance procedures and Mel/MMel requirements, i.e. an aircraft to be approved Etops operation need three independents sources of electral power, the 767 has four, two engines driven generators, APU and HDG, you could be dispatched with the APU u/s, only if the HDG is ok.

Another particularity of this kind of operation, is the procedure that involves the engines checks, as oil measurement, two mechanicals are needed to perform this, one for each engine, because this assure to reduce the possibility to duplicate mistakes.

Prior to each Etops flight, maintenance must has been made an entry in the book stated "etops approved" only with this condition you will be able to start a flight extended range operation.

Also, the crew members need to hold Etops Qualification, that involves special procedures like drift down, critical scenarios, etc.

Yours faithfully,

12th Jun 2003, 17:25
Sorry - it might be a silly question, but what is a HDG (I'm sure it is not Hand Driven Generator).

12th Jun 2003, 17:34
Hydraulic Driven Generator (usually centre system,blue for the old timers like me)on the 76.

12th Jun 2003, 17:51
Sorry about my brief about HDG.

This means Hydraulic driven generator, and is automatically powered by the center hydraulic system when electrical power is lost in the 767s.

hand driven generator...good joke!!! i will remember it in my next recurrent course!


12th Jun 2003, 18:13
Probably a few more things to consider.

A read through FAA AC 120-42A (http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/2638EAF8B89680A8862569BA00751C8C?OpenDocument&Highlight=etops) is worth the time ......

The basic idea is to achieve something comparable to four-motor reliability. It is not just a question of number of motors but overall system redundancy and reliability.

(a) each airframe/engine combination is considered separately

(b) individual critical systems are considered. So, for instance, a particular widget may need particular SBs etc to be incorporated for the widget to qualify for use in ETOPs operations by virtue of different reliability characteristics. This sort of thing can make configuration status tracking a bit of a nightmare for the maintenance planning and records people if an operator runs a mixed ETOPs/non-ETOPs fleet .... Alternatively, for example, you may need to run the APU to provide electrical redundancy during the ETOPs part of the flight .. and so on ...

(c) it follows that the operator must have appropriate systems in place to permit a reasonable probability of achieving the theoretical reliability figures tossed around during the ETOPs certification ..

(i) reliability monitoring and tracking is a requirement for the tech services people

(ii) the maintenance systems overall need to be reviewed and approved. Personnel need to be trained and approved ..

(iii) the pilot group needs to be trained and approved ...

12th Jun 2003, 19:02
Many thanks everyone. Perfectly clear.

12th Jun 2003, 19:17
I learned something too - Thanks.

13th Jun 2003, 00:59
I've always heard them called HMG's for hydraulic motor generator.

jorg - two mechs are NOT req'd to do oil checks it is down to company proceedures. I have worked for ones where 2 are required and others where only one can do the job. As long as the NAA are happy with the proceedures in place that is all that matters.

Individual componants may also have an ETOPS restriction. For example a fuel feed pipe of a certain dash number may not be ETOPS compliant IAW the IPC. I know on a certain engine type the spinner is ETOPs critical!!? To prevent problems ETOPS authorised airlines insist all componants aquired are ETOPS compliant even if they are not going onto an ETOPS a/c.

An inoperative power source may not mean that the a/c is no longer ETOPS. It may however reduce the duration fron say 180 to 120 mins. Information like this will be found in the MEL

Hope this additional info helps.

23rd Jun 2003, 08:14