RR 747-400s... noise problems loom?
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Rolls Powered 747-400s
Its about to get rough on operators of Rolls 747-400s at Heathrow.
Here is a link:
http://www.dft.gov.uk/stellent/group...ion_029818.pdf
and here is an excerpt from the link:
Some of the issues addressed include:
Proposal to retain the QC system (Para. 7.4)
"… most aircraft currently operating at night … have operational noise levels that accord with their present QC classification." (Para. 7.6)
"The key aircraft found to be noisier than its QC classification is the Boeing 747-400 powered by Rolls Royce (RR) engines which is the main type used by airlines in the NQP [Night Quota Period] at Heathrow." (Para. 7.6)
"… differences between measured operational noise and the noise performance of aircraft … have been brought to the attention of the international technical experts currently examining the ICAO noise certification requirements. … We are pressing for the certification requirements to be updated, to reflect modern operating procedures and conditions, and to be made more rigorous." (Para. 7.8)
Not consulting on whether to use operational noise to replace certification as basis of restrictions because that is precluded by Directive 2002/30/EC.
Changes to QC system are permitted. Considerations are:
Extending QC scale downwards by a further 3 dB and introduce QC/0.25. Impact would be that some B757, B737, MD80, MD90, and B717 would no longer be exempt. (Para. 7.14-7.15)
Whether to keep the adjustment for arrivals at -9 EPNdB. Gov't favors keeping as is. (Para. 7.18-7.21)
Whether to prohibit QC/4 aircraft from being scheduled or from operating in the present night quota period. [The operating ban would affect delayed 747 departures.] (Para. 7.22)
If the QC/4 ban is implemented, then the Gov't proposes:
Reduce nighttime operational noise limit from 87 to 84 dBA. (Para. 7.23(a)) [Would this affect heavy twins?]
Set new night-time noise insulation criteria based on 747-400/RR. (Para. 7.23(b))
Consider whether to let QC4 aircraft would be allowed to operate in current shoulder periods (2300-2330, 0600-0700) if these were brought within the night quota period. (Para. 7.23(c))
Here is a link:
http://www.dft.gov.uk/stellent/group...ion_029818.pdf
and here is an excerpt from the link:
Some of the issues addressed include:
Proposal to retain the QC system (Para. 7.4)
"… most aircraft currently operating at night … have operational noise levels that accord with their present QC classification." (Para. 7.6)
"The key aircraft found to be noisier than its QC classification is the Boeing 747-400 powered by Rolls Royce (RR) engines which is the main type used by airlines in the NQP [Night Quota Period] at Heathrow." (Para. 7.6)
"… differences between measured operational noise and the noise performance of aircraft … have been brought to the attention of the international technical experts currently examining the ICAO noise certification requirements. … We are pressing for the certification requirements to be updated, to reflect modern operating procedures and conditions, and to be made more rigorous." (Para. 7.8)
Not consulting on whether to use operational noise to replace certification as basis of restrictions because that is precluded by Directive 2002/30/EC.
Changes to QC system are permitted. Considerations are:
Extending QC scale downwards by a further 3 dB and introduce QC/0.25. Impact would be that some B757, B737, MD80, MD90, and B717 would no longer be exempt. (Para. 7.14-7.15)
Whether to keep the adjustment for arrivals at -9 EPNdB. Gov't favors keeping as is. (Para. 7.18-7.21)
Whether to prohibit QC/4 aircraft from being scheduled or from operating in the present night quota period. [The operating ban would affect delayed 747 departures.] (Para. 7.22)
If the QC/4 ban is implemented, then the Gov't proposes:
Reduce nighttime operational noise limit from 87 to 84 dBA. (Para. 7.23(a)) [Would this affect heavy twins?]
Set new night-time noise insulation criteria based on 747-400/RR. (Para. 7.23(b))
Consider whether to let QC4 aircraft would be allowed to operate in current shoulder periods (2300-2330, 0600-0700) if these were brought within the night quota period. (Para. 7.23(c))
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Does this report (I haven't looked at the base report) break it down by operator?
The 747/400/RR operators are BA/QF/CX.
I know BA use F25 as the standard landing config. After BKK, do QF use F30? What about CX?
There could be a correlation between operator, land flap and noise.
Where are the noise measurement points? Could be that the gear lowering points are also relevant....
The 747/400/RR operators are BA/QF/CX.
I know BA use F25 as the standard landing config. After BKK, do QF use F30? What about CX?
There could be a correlation between operator, land flap and noise.
Where are the noise measurement points? Could be that the gear lowering points are also relevant....
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It is not broken down by operator. It would affect all operators for RR powered 744s at London area airports. Flaps have nothing to do with it. Both landing flaps have been shown to exceed the noise certification by a large margin. 
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747FOCAL - what you say is very interesting. If even at Flap 25, the RR aircraft still exceed their F30 noise certification levels, then what do you think could be the cause of the high noise levels?
Also, any ideas why the PW/GE 744s don't suffer from the same problem?
Also, any ideas why the PW/GE 744s don't suffer from the same problem?
