The most controversial of the departures from the original transcript was the addition of this infamous phrase, which was dealt with at length in the Mahon Report:

Time 0047:55 Bit thick here, eh Bert?

This conjures up images of poor visibility and of an aircraft being operated incompetently and about to stray into danger. The IIC claimed the words were definitely spoken to a flight engineer by an unknown person. The problem is that no other person is known to have heard it. Certainly, none of those words came from the CVR specialists. The phrase simply was not sufficiently intelligible for them to transcribe in accordance with the training they had received (Mahon 1981, 37-38).

Several factors can be taken into account to assess the validity of the transcribed phrase.

1.   The CVR Group, accompanied by a number of experts, could not agree on any words being clear enough in that passage to issue a definitive transcription. When Mahon went to the Washington laboratory and listened to the tape in the company of specialists with credentials similar to the CVR Group, they all agreed that the phrase was far too garbled to be given any reliable transcription. Specifically, Mahon discovered that a word sounding like “here” was not heard by him or any of the other specialists present; the speech sounds were vaguely similar to “bit thick eh Bert” (Mahon 1981, 38).
 
2.   The IIC claimed that he and a Farnborough specialist heard the words. When Mahon himself went to Farnborough he discovered that the “specialist” was a “filtering expert”, a flight recorder technician working in the audio laboratory whose job it was to operate the lab’s equipment (Mahon 1981, 38-39). There were several qualified investigators present with Mahon and the technician when he listened to the recording there, including the Chief Inspector of Air Accidents for the United Kingdom. The specialist investigators at Farnborough declined to transcribe the phrase as it appeared in the published form, and this time the technician did not give an opinion at all.

In later evidence 6 the IIC claimed that Mahon heard the word “here” as “there” and he (the IIC) “…would now tend to agree.” This difference in words changes the whole meaning of the phrase, and negates any implication that the aircraft was flying in cloud. Mahon wrote that neither he, nor Counsel assisting him, nor the Farnborough officials had heard any such word (i.e. “here”) at all.

In a newspaper article published in 2004 the then-retired Chief Inspector was challenged, and admitted he may have got the name "Bert" wrong. "But the 'bit thick here' comment was there," he said (Loughlin 2004).

3.    It was certainly possible that the IIC made an genuine error in reaching this result. In that case, there was no mechanism in the system that could have identified and rectified the error. This was because he had taken sole control of the CVR and no-one was able to monitor him.

This illustrates why no single person ought to be permitted to determine the outcome of any CVR investigation. Nor should they decide what should and should not be included in any CVR transcription, including during editing.

4.   The IIC said that a question was being asked of the flight engineer, referred to as “Bert.” He knew that the flight engineer’s name was not “Bert.” In fact, there was no flight crew member named “Bert”.
5.   The word “thick” strongly implies the aircraft was flying in or near cloud. However, passengers’ photographs from cameras recovered from the crash site did not support this; a number of photographs showed sunlight streaming into the cabin right up until impact (Vette and Macdonald 1983).

These failures mean that the IIC acted beyond proper and appropriate boundaries when he submitted these words. They should not have been transcribed.

Any one of the failures identified during the transcription process would be enough to cause the CVR Group to correctly render the phrase as unintelligible. Alternatively, during the interpretation phase of the CVR study it would have been adjudged as: not sufficiently intelligible to be given any reliable meaning or interpretation.

In a press release made at the time the IIC claimed that: “Just because there was no crew member named Bert that doesn’t prove that the words weren’t spoken. I knew they were from the long hours spent listening to the tape” (Macfarlane 1991, 329). This statement reveals another flaw in the process with which the IIC transcribed the CVR. Audio engineers and flight recorder analysts are very careful not to spend long periods, especially alone and unmonitored, trying to understand words. As a trainee flight recorder specialist learns early on in their career:, after a while the brain will begin to hear things that aren’t there.

“Bit thick eh Bert,” was far more likely to be: “This Is Cape Bird”

There was strong evidence to suggest that the words spoken were probably: “This is Cape Bird.” Based on the route shown during the Route Clearance Unit (RCU) briefing the crew may have believed that it was Cape Bird visible on the left hand side of the aircraft at the time these exchanges took place, with the next landmark to come into view on the left expected to be Cape Royds. In fact it would not be Cape Royds, but rather Cape Tennyson, which was probably subtending the same angle and thus a similar visual aspect as might have been expected from Cape Royds (Vette and MacDonald 1983: 134). 

How the crew mistook Cape Tennyson for Cape Royds (after Vette and Macdonald 1983).

 

The words “I reckon Bird’s through here” were clearly spoken seconds afterward, as confirmed by the CVR Group. Contextually, the phrase would not be out of place. However mere suggestion that the words spoken were “This is Cape Bird” fails the test required to insert them as a definitive passage 7 into the transcript.

In other words, ’probably’ isn’t good enough; the only acceptable test is ’definitely’. And the only acceptable method by which 'definitely' can be achieved is by way of a vote, of a group of specialists that themselves meet certain criteria. Clearly then, the treatment of the CVR failed to meet these criteria. The IIC failed to show that his version of the phrase was spoken. Thus, the original conclusion reached by the specialist CVR Group that the words are unintelligible, could be the only correct result.

Here is another disputed phrase:

Time 0048:05 You’re really a long while on instruments this time are you?

For the same reasons given earlier, the CVR Group determined that this passage was not sufficiently intelligible to be given any reliable meaning, and the public inquiry agreed. In fact when Mahon and the others listened, once again utilising both the Washington and Farnborough audio laboratories, they kept hearing “this time” as “that time,” which of course makes the supposed sentence grammatical nonsense. Moreover it sounded like the words before “instruments” came from another speaker, dealing with an entirely different subject (Mahon 1981, 38). In other words, the published transcript formed two conversations into a single phrase. This leads one to the conclusion that the aircraft was being operated solely by reference to the flight instruments, further implying the aircraft was flying in cloud or poor weather.

There are a number of other examples of disputed interpretations in the published transcript.

Consider these:

Time 0047:28 What’s wrong here
                          Make up your mind soon or (you got to go ...)
Time 0047:55 It’s not right
Time 0034:21 Damn I had whole series of figures – visual figures holding TACAN during the descent

The IIC claimed the first two comments were made by the flight engineers, and the last by one of the pilots. After detailed expert analysis, the CVR Group was unable to assign any of these added phrases as part of their original transcription. The last example makes no sense whatsoever, and therefore analysis is pointless. It is most unlikely that these words were spoken as they appear in the published transcript.

Non-authenticated, nonsensical additions aren’t the only method by which the substituted transcript differs from the original transcript.

Consider this exchange:
Time 0039:49   Having a bit of radio trouble at the moment
                            Have you got the squelch off?
                            Clearance to go down.
                            Say again?
                            Have you got the squelch off on that?
Time 0039:58   Yes, on both.

This exchange showed that the crew were actively troubleshooting the reasons why short-range VHF communications from “Ice Tower” 8 were not being received. The crew were utilising their wealth of knowledge and experience to resolve the anomaly. The words are clear and unambiguous, and were signed off unanimously by the CVR Group as having definitely been spoken.

This passage does not appear in the published transcript. The IIC claimed that it was necessary to edit out that phrase to comply with the wishes of the Air Line Pilots’ Association (Macfarlane 1991, 332). How he arrived at that reasoning is not known, because during the Royal Commission hearings it was counsel for the Association who drew attention to the omission and criticised the IIC for omitting it.

Here is another alteration:

Time 0045:36 Taylor on the right now

The flight’s Antarctic commentator spoke these words as authenticated by the CVR Group. Tone and inflection indicate a positive statement in the form known as an ‘absolute phrase’. He was thus likely to have been pointing out the believed location of the Taylor Valley to the other crew members. The published transcript however converts the phrase into an interrogative:

      The Taylor or the Wright now or do yah?

Note that the word “The” is added at the beginning of the phrase, “on” becomes “or,” and the word “right” is replaced with its homonym “Wright,” presumably meaning the Wright Valley. Then the supposed words “…or do yah?” end the phrase. The captain then supposedly says:

        No I prefer here first!

Once again, the substituted words were not heard by the CVR Group or anyone other than the IIC. This shifts the context from the crew carefully reaffirming their position by clearly identifying features visually, and strengthened the IIC’s conclusion that the crew were indecisive and unsure of their position or of what to do (Mahon 1981, 43).

A further change was:

Time 0041:40 Tell him we can make a visual descent
0041:45           My God
                          On a grid of one eight zero....

Taken out of context, the inserted "My God" comment implies someone was expressing shock at the decision to descend visually, and probably began the myth that the flight engineers were "kicking and screaming" while the pilots flew them into the ground. But in the following few minutes there was no other comment made that could be interpreted as expressing shock or even puzzlement at that decision.

As Mahon eloquently put it: "It is not possible that someone who was deeply concerned would content himself with a brief invocation to the Deity and thereafter remain silent” (Mahon 1981, 39). There is little question that the comment was made, however it makes far more sense that it came from the galley, made by a passenger possibly marvelling at the view.

For the sake of balance, it is necessary to point out that the CVR Group did authenticate at least two seemingly disturbing phrases:

Time 0048:55 ...have we got them on the tower?
                         No...I’ll try them again
 
0049:24         I don’t like this
0049:25         Have you got anything from him?
             No

The “I don’t like this” comment was voiced by the duty flight engineer, and Cooper says the tone and inflection indicated considerable concern. It fell within the above exchange between the pilots regarding the lack of VHF communications with “Ice Tower.”

Again, the context must be examined in order to correctly interpret the meaning of this passage, rather than assuming theories of “mounting alarm” from the flight engineers being ignored by the pilots. If that had been the case the flight engineers would not have stopped issuing warnings until the pilots acted. As this did not occur it strongly suggests a less immediate reason for the comment. It is likely that the duty flight engineer was referring to the exchange between the pilots and was simply expressing his unease that, contrary to expectation, no VHF communications were taking place. To put it another way perhaps, if the engineer had issued a warning  the “crew loop” would have required that the flight engineer qualify the statement by clearly defining exactly what was bothering him, and then suggesting a course of action.

This second example serves as a further graphic reminder to leave CVR interpretation to the experts:

Time 0044:06 Where are we? (Question mark inserted by the IIC)

Upon reading that this remark was recorded on the CVR, breathless intonations from the armchair experts predictably concluded that the crew was lost. Naturally it didn’t take long for the phrase to morph into something more suitable for the masses, as this erroneous quote from a book reviewer at the time shows: “where the hell are we?” It certainly looks as though the speaker is asking a question, particularly as the IIC added the interrogative question mark. In fact the speaker was more likely to have been making a statement, the indication of which is revealed immediately in the next line:

Time 0044:06 About up to here now? (Question mark inserted by the IIC)
(sound similar to rustling paper)

The speaker was likely referring to the aircraft's track as depicted on a chart and merely pointing out the aircraft’s position along it. This is not an uncommon thing for a pilot to do, particularly when navigating visually over largely featureless terrain. In fact, this forms part of normal map reading technique and further indicates the aircraft was navigating clear of poor weather.

Several minutes later, the captain said:

We’re 26 miles north; we’ll have to climb...

This statement was followed by a short tactical discussion on the best ways in which to achieve this. It was during this exchange that the Ground Proximity Warning System alarm sounded. The crew would have been looking outside, only to see a flat sheet of ice 1,500ft beneath them, cliffs to either side, and a horizon that was miles off in the distance. Disbelieving the alarm, they nevertheless executed the procedure to get them away from the ground quickly as they had been trained, but to no avail.