CASA $1,000 Useless Compass Check
You quoted much of what AOPA had to say. Please send me a link to the original "Waddington Effect" paper
I have absolutely no idea what AOPA ( I presume you mean AOPA/USA) has said on the subject.
My knowledge of the subject is only a little bit second hand, as it comes from an RAF maintenance officer who was a distant but fascinating relation.
As for your demands for a (academic) paper, I dare say that, at the time, the chaps were a little busy fighting Hitler, and formal studies, collection of statistics etc was not front of mind.
Indeed, I have only heard it called the "Waddington Effect" in recent years, but civily the general principles were well understood by the 1950s, it was covered in Eng1 at Sydney Uni., and undoubtedly in Engineering courses at other universities. The WWII RAF experiences were quoted.
In the RAF setup, Squadron/Wing COs had wide ranging authority, their Engineering Officers --- just from day to day experience saw the serviceability of otherwise of aircraft, particularly larger aircraft, and convinced their COs of the "if it ain't broke, don't fix it" approach.
Quite simple, it worked.
The first "studies", of which I am aware, which might satisfy your demand for a "paper", was work by United Airlines in the late '40s or early 1950's, and as developed over the years, has become the basis of much civil and military maintenance control processes. --- on condition maintenance.
Re.maintenance error, in the modern airline sphere, it accounts for the "most probable cause" or "root cause" in about 35% of accidents, not a trivial percentage.
Tootle pip!!
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Sure Leadsled
I just wanted to read the original paper. The only thing I could find was a link to a book about submarine operations.
Seems its written in "C. H. Waddington, OR in World War 2: Operational Research against the U-Boat"
So I am trying to get a copy !
I just wanted to read the original paper. The only thing I could find was a link to a book about submarine operations.
Seems its written in "C. H. Waddington, OR in World War 2: Operational Research against the U-Boat"
So I am trying to get a copy !
Hasher,
Try and get your mind around the idea that it didn't start with a "paper", although there may well have SUBSEQUENTLY been something written that gave rise to the name "Waddington" effect, but it was certainly NOT invented at or confined to Waddington.
Indeed, one of the interesting stories of the day was the introduction of Catalinas with PW1830 engines, at the other end of the country, one of the first experiences of US aircraft and engines in the RAF.
The reliability of the engines came as somewhat of a surprise to those only familiar with English engines. A engine that could run for twelve hours plus, and only needed the oil topping off to do another twelve hours, without having to replace a single cylinder, came as a bit of a revelation.
Engines with overhaul lives measure in 1000s of hours, not 100s (if you were lucky) were just not believed, at first.
To not have to tighten nuts using a micrometer to measure stud extension, alone, saved hours. The use of gas pressurised compression rings on pistons, as opposed to spring steel or other solid and inflexible rings were another revelation.
I think "necessity is the mother of invention" just about covers it.
Tootle pip!!
Try and get your mind around the idea that it didn't start with a "paper", although there may well have SUBSEQUENTLY been something written that gave rise to the name "Waddington" effect, but it was certainly NOT invented at or confined to Waddington.
Indeed, one of the interesting stories of the day was the introduction of Catalinas with PW1830 engines, at the other end of the country, one of the first experiences of US aircraft and engines in the RAF.
The reliability of the engines came as somewhat of a surprise to those only familiar with English engines. A engine that could run for twelve hours plus, and only needed the oil topping off to do another twelve hours, without having to replace a single cylinder, came as a bit of a revelation.
Engines with overhaul lives measure in 1000s of hours, not 100s (if you were lucky) were just not believed, at first.
To not have to tighten nuts using a micrometer to measure stud extension, alone, saved hours. The use of gas pressurised compression rings on pistons, as opposed to spring steel or other solid and inflexible rings were another revelation.
I think "necessity is the mother of invention" just about covers it.
Tootle pip!!
My understanding is that when the new 100.5 regs were introduced, it actually omitted compass swings. At the time of our last 100 hourly ours was done expecting that CASA would soon correct that.
100.5 re-introduces a range of periodic checks that were previously dropped as being not warranted. eg, fuel gauge calibration.
I did the exercise a while back of going through our log books and putting in a table all the calibration results for the key instruments over the aircraft's 30-odd year life. The main thing I leaned is that many LAME's can't calibrate for sh*t. With full trend data, some calibrations have clearly been just plain wrong. Watching our last fuel tank calibration, it was clear that the guys doing it didn't understand what they were doing . But to challenge it means another fuel drain and repeating the exercise which would blow another $1500. And our electronic fuel totaliser is more accurate anyway.
The other thing I learned is that most instrument don't change in calibration significantly. I challenge those supporting regular calibration to do the exercise.
100.5 re-introduces a range of periodic checks that were previously dropped as being not warranted. eg, fuel gauge calibration.
I did the exercise a while back of going through our log books and putting in a table all the calibration results for the key instruments over the aircraft's 30-odd year life. The main thing I leaned is that many LAME's can't calibrate for sh*t. With full trend data, some calibrations have clearly been just plain wrong. Watching our last fuel tank calibration, it was clear that the guys doing it didn't understand what they were doing . But to challenge it means another fuel drain and repeating the exercise which would blow another $1500. And our electronic fuel totaliser is more accurate anyway.
The other thing I learned is that most instrument don't change in calibration significantly. I challenge those supporting regular calibration to do the exercise.
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Akro 
Nail on head.
Last 1000hrs 5 years, no notable changes at all. And fuel accuracy within a litre over 250. In fact most error comes from venting of fuel on hot days out the breather.
Nail on head.
Last 1000hrs 5 years, no notable changes at all. And fuel accuracy within a litre over 250. In fact most error comes from venting of fuel on hot days out the breather.
Hear! Hear! OA.
It is obvious to me that the people who make these rules are ignorant of and uninterested in objective facts and data.
"No amount of science or hard data can over-come the comforts offered by a closely held superstition or belief."
It is obvious to me that the people who make these rules are ignorant of and uninterested in objective facts and data.
"No amount of science or hard data can over-come the comforts offered by a closely held superstition or belief."
This is why we have religious wars. It's 2015 people
It’s also why there are still mandatory compass and fuel gauge calibrations for private aircraft in Australia, and why you refuse to accept the reality of the Waddington Effect.
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No I refuse to accept The Waddington effect in your terms.It's a bastardisation of terms used in political motive to push a point (Probably by AOPA). Maybe even to sell a book. I believe it exists but not in the extent purported in this thread. Only modern evidence was in a MIT study and that was 1.4% of aircraft availability.
Waddington Effect is borrowing the term used from CH Waddingtons biological studies . I listed all of this in a post previously.
Waddington Effect is borrowing the term used from CH Waddingtons biological studies . I listed all of this in a post previously.
I must say, Hasherucf, your googling skills seem a little poor, despite Leaddie urging you to 'try harder'.
3 minutes of googling led me to, for example, an archived post on the US Defense Acquisition Portal by the Director of Logistics and Sustainment Centre, in which he commends for reading an article in Sport Aviation Magazine entitled “The Waddington Effect: More Maintenance Isn’t Necessarily Better”. The Director comments:
The “The Waddington Effect, C4U-Compliance, and Subsequent Impact on Force Readiness” article is available here: http://cmapspublic.ihmc.us/rid=1HTKPYHY3-10D9MZ0-11ML/ I quote but a few paras:
[My bolding]
I also note but a few paragraphs from the latter report (available here (WARNING: IT IS A BIG FILE): http://reliabilityweb.com/ee-assets/...n_and_Heap.pdf
[My bolding]
In short: Belief versus science and hard data.
Upon which do you reckon periodic calibrations of e.g. compasses and fuel gauges on private aircraft in Australia have been mandated?
3 minutes of googling led me to, for example, an archived post on the US Defense Acquisition Portal by the Director of Logistics and Sustainment Centre, in which he commends for reading an article in Sport Aviation Magazine entitled “The Waddington Effect: More Maintenance Isn’t Necessarily Better”. The Director comments:
The author offers interesting perspectives on the history of Reliability Centered Maintenance (RCM), including the once-classified work by H.C Waddington and his British Coastal Command Operational Research Section colleagues during World War II. In it, he also cites a separate, yet equally compelling article in the September 2010 Bulletin of Military Operational Research Phalanx Magazine entitled “ The Waddington Effect, C4U-Compliance, and Subsequent Impact on Force Readiness”, as well as a pioneering 1978 RCM report written for the Department of Defense entitled ”Reliability Centered Maintenance”, by F. Stanley Nowlan and Howard F. Heap.
… Conventional wisdom held that, if more preventive maintenance events were performed on each aircraft, fewer problems would exist – and potential problems could be caught and fixed – and thus the effectiveness of the fleet would surely improve. Conventional wisdom was, as is so often the case, wrong. It would take Conrad Hal (C.H.) Waddington and his Operational Research team to prove just how wrong.
C. H. Waddington (1905-1975) is best known, today, as one of the first developmental geneticists – and as a person who did not believe that genetics, embryology, and evolution were separate sciences. But his interests and contributions covered a much broader spectrum. Those individuals involved in the field of Artificial Intelligence recognize him, or should, as one of the pioneers of the optimization technique designated as Genetic Algorithms. Those in the military recognize him, or should, as one of the leaders in the development of a new, unorthodox, and – at one time – highly suspect (i.e., by the military) approach to military planning, both strategic and tactical.
…
..[B]efore scurrying about to provide a slick briefing on a scheme that might or might not work, Waddington and his team had the audacity to stop and think. They requested and analysed the supporting data, talked with maintenance crews, and took time to carefully and personally observe actual maintenance events (a decision quite unlike that of too many “analysts” who prefer to remain in their warm and comfortable offices, poring over and processing data provided from “the outside”). Furthermore, rather than getting the wrong answer, or the politically correct answer, fast, these Operational Researchers trod the lonely path of seeking a proper, effective, and practical answer.
…
The conclusion Waddington and his group reached … was, in Waddington’s own words, that “inspection tends to increase breakdowns, and this can only be because it is doing positive harm by disturbing a relatively satisfactory state of affairs. Secondly, there is no sign that the rate of breakdown is beginning to increase again after the 40-50 flying hours, when the aircraft is coming due for its next [preventive maintenance event].”
…
In other words the Waddington Effect is defined as a “spike” in the number and frequency of unscheduled events “closely” following a scheduled event – followed in turn by a gradual decline in the a rate of occurrence of unscheduled events to a “more normal level,” until a repeat of this same, troublesome effect following the next scheduled maintenance event.
…
[And just to support Leaddie’s earlier post: Once these recommendations were implemented the effective size of the British Coastal Command air fleet was increased by more than 60 percent! In other words, a change in maintenance protocols and their documentation (as motivated by the identification of the Waddington Effect) was as effective (and far less costly or time consuming) as the allocation of an additional 60 percent more aircraft….
C. H. Waddington (1905-1975) is best known, today, as one of the first developmental geneticists – and as a person who did not believe that genetics, embryology, and evolution were separate sciences. But his interests and contributions covered a much broader spectrum. Those individuals involved in the field of Artificial Intelligence recognize him, or should, as one of the pioneers of the optimization technique designated as Genetic Algorithms. Those in the military recognize him, or should, as one of the leaders in the development of a new, unorthodox, and – at one time – highly suspect (i.e., by the military) approach to military planning, both strategic and tactical.
…
..[B]efore scurrying about to provide a slick briefing on a scheme that might or might not work, Waddington and his team had the audacity to stop and think. They requested and analysed the supporting data, talked with maintenance crews, and took time to carefully and personally observe actual maintenance events (a decision quite unlike that of too many “analysts” who prefer to remain in their warm and comfortable offices, poring over and processing data provided from “the outside”). Furthermore, rather than getting the wrong answer, or the politically correct answer, fast, these Operational Researchers trod the lonely path of seeking a proper, effective, and practical answer.
…
The conclusion Waddington and his group reached … was, in Waddington’s own words, that “inspection tends to increase breakdowns, and this can only be because it is doing positive harm by disturbing a relatively satisfactory state of affairs. Secondly, there is no sign that the rate of breakdown is beginning to increase again after the 40-50 flying hours, when the aircraft is coming due for its next [preventive maintenance event].”
…
In other words the Waddington Effect is defined as a “spike” in the number and frequency of unscheduled events “closely” following a scheduled event – followed in turn by a gradual decline in the a rate of occurrence of unscheduled events to a “more normal level,” until a repeat of this same, troublesome effect following the next scheduled maintenance event.
…
[And just to support Leaddie’s earlier post: Once these recommendations were implemented the effective size of the British Coastal Command air fleet was increased by more than 60 percent! In other words, a change in maintenance protocols and their documentation (as motivated by the identification of the Waddington Effect) was as effective (and far less costly or time consuming) as the allocation of an additional 60 percent more aircraft….
I also note but a few paragraphs from the latter report (available here (WARNING: IT IS A BIG FILE): http://reliabilityweb.com/ee-assets/...n_and_Heap.pdf
One of the underlying assumptions of maintenance theory has always been that there is a fundamental cause-and-effect relationship between scheduled maintenance and operating reliability. This assumption was based on the intuitive belief that because mechanical parts wear out, the reliability of any equipment is directly related to operating age. It therefore followed that the more frequently equipment was overhauled, the better protected it was against the likelihood of failure. The only problem was in determining what age limit was necessary to assure reliable operation.
In the case of aircraft it was commonly assumed that all reliability problems were directly related to operational safety. Over the years, however, it was found that many types of failures could not be prevented not matter how intensive the maintenance activities. …
A major question still remained, however, concerning the relationship between scheduled maintenance and reliability. Despite the time-honoured belief that reliability was related to the intervals between scheduled overhauls, searching studies based on actuarial analysis of failure data suggested that the traditional hard-time policies were, apart from their expense, ineffective in controlling failure rates. This was not because the intervals were not short enough, and surely not because the teardown inspections were not sufficiently thorough. Rather, it was because, contrary to expectations, for many items the likelihood of failure did not in fact increase with increasing operating age. Consequently, a maintenance policy based exclusively on some maximum operating age would, no matter what the age limit, have little or no effect on the failure rate. …
In the case of aircraft it was commonly assumed that all reliability problems were directly related to operational safety. Over the years, however, it was found that many types of failures could not be prevented not matter how intensive the maintenance activities. …
A major question still remained, however, concerning the relationship between scheduled maintenance and reliability. Despite the time-honoured belief that reliability was related to the intervals between scheduled overhauls, searching studies based on actuarial analysis of failure data suggested that the traditional hard-time policies were, apart from their expense, ineffective in controlling failure rates. This was not because the intervals were not short enough, and surely not because the teardown inspections were not sufficiently thorough. Rather, it was because, contrary to expectations, for many items the likelihood of failure did not in fact increase with increasing operating age. Consequently, a maintenance policy based exclusively on some maximum operating age would, no matter what the age limit, have little or no effect on the failure rate. …
In short: Belief versus science and hard data.
Upon which do you reckon periodic calibrations of e.g. compasses and fuel gauges on private aircraft in Australia have been mandated?
Last edited by Creampuff; 28th Jan 2015 at 05:28.
Hash, I can assure you that the Waddington effect is real.
In relation to maintenance the probability of stuffing something up when you reassemble and install it is not zero and the defect may not be discovered in initial testing. This effect gives rise to what is termed "infant mortality" - failure shorty after installation in components.
I independently proved the existence of this effect by studying and analysing failures of autopilot gyros in the Ansett aircraft fleet in the late 1970's. Almost all of them occurred shortly after overhaul and reinstalllation. They had very delicate bearings which were easily damaged. We increased their reliability by doubling their life limits.
In relation to maintenance the probability of stuffing something up when you reassemble and install it is not zero and the defect may not be discovered in initial testing. This effect gives rise to what is termed "infant mortality" - failure shorty after installation in components.
I independently proved the existence of this effect by studying and analysing failures of autopilot gyros in the Ansett aircraft fleet in the late 1970's. Almost all of them occurred shortly after overhaul and reinstalllation. They had very delicate bearings which were easily damaged. We increased their reliability by doubling their life limits.
We increased their reliability by doubling their life limits.
Despite the time-honoured belief that reliability was related to the intervals between scheduled overhauls, searching studies based on actuarial analysis of failure data suggested that the traditional hard-time policies were, apart from their expense, ineffective in controlling failure rates. … Consequently, a maintenance policy based exclusively on some maximum operating age would, no matter what the age limit, have little or no effect on the failure rate. …
