Re: Stage III definition

Date:         06 Aug 98 23:22:37 
From: (Darren Rhodes)
Organization: Daz Technology
References:   1
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On 29 Jul 98 00:29:26 , JF Mezei <> wrote:

>The other day, I noticed a noisy plane overhead (I live 8.5 km from an
>I looked and low and behold it was an F28. (Canadian Airlines).
>It sounded just as "bad" as a DC-9 or 737-200.

A perfectly reasonable assumption. The F28 has Rolls Royce Spey
engines of various marks. These are essentially lower thrust variants
of Spey engines used in BAC1-11 aircraft. Military variants were also
used in UK Phantoms and Bucaneers. They are low bypass ratio (1.0)
engines and hence are pretty noisy.

>Will Stage III only affect planes with a certain weight, or is it an all
>encompassing regulation about noise ?

>In other words, would it be possible to have, after STAGE III deadline,
>an ultralight aircraft that makes more noise than a 707 not outfitted
>with a hushkit ?

No, all jet transport aircraft must be certificated to Stage 3 rules.
Below a certain weight (T/O between 20 and 48 tonnes depending on the
no. of engines) you must not exceed a certain noise level (89EPNdB).

>And as far as the F28 is concerned, are its engines much quieter than
>that of the DC-9 or 737-200 ? Is the F28 considered Stage III compliant?

Takeoff EPNL:

Fokker F.28 Mk 4000:	92.9
Douglas DC9-10:	91.4
Boeing 737-200:		92.0-97.0 (depending on model)

Sideline EPNL:

Fokker F.28 Mk 4000:	101.7
Douglas DC9-10:	100.8
Boeing 737-200:		100-101

Approach EPNL:

Fokker F.28 Mk 4000:	99.4-101.4
Douglas DC9-10:	100-103
Boeing 737-200:		102-105

See above, actually noisier than a DC9-10 at takeoff certification
point (measured at 6.5km from start of takeoff roll).

It clearly isn't stage 3 compliant. There is a program to re-engine it
with Tay engines. The heavier engines require a fuselage plug to
balance the aircraft - much like the MD80--->MD90 change, although
this is on existing aircraft. Not heard of any orders for the
coversion yet.

Mr. Darren P. Rhodes, BEng. (Hons)        | Aircraft Performance
Email:  | Analysis & Noise
Web:     | Specialist