Loran From Germany, joined Jul 2005, 485 posts, RR: 2 Posted (1 year 6 months 14 hours ago) and read 2945 times:
I am a little confused between the MTOWs of the 747-300 in comparison to the 747-300SR. There is a major discrepancy between the various fleet lists about which airframes are -300 and which ones are -300SR versions from JAL.
ACAS (Flightglobal) e.g. reports only two airframes being -300SR versions (5N-DBM with Maxair and VP-BGW with Transaero). Their MTOWs are quoted as 371’946.
I have flown on Transaero’s VP-BGU, a regular -300 which in return is quoted with an MTOW of 310’000. I have also flown on QF’s VH-EBY which has an MTOW of 377’843 according to ACAS.
Could someone clarify why the -300SR version has a higher certified MTOW than the regular -300? Is possibly the strengthening of the airframe for the shorter FH/Cycle ratio of the SR that heavy?
747classic From Netherlands, joined Aug 2009, 1941 posts, RR: 13 Reply 2, posted (1 year 5 months 4 weeks 1 day 8 hours ago) and read 2735 times:
All 747-300 aircraft (incl. the four ex.JAL 747-346SR's) are structural capable of a MTOW of 833.000 lbs or 377.800 kgs.
(377.843 kgs, if you perform an exact lbs-kgs. conversion)
- Structural you only can lower the operating weights (MTOW and LW) by installing an other (lighter) wheel assy type.
- All certified engines types on the 747-300 series are capable to support a 833.000 lbs. TOW. All ex.JAL 747-346 aircraft are powered by JT9D-7R4G2 engines, in the 747-300SR configuration they can be derated to increase engine life, but they can be operated at certified max. T/O thrust.
- A wing type 6 and higher as installed on the 747-300 series is always capable of 833.000 lbs.
However you can decrease the MTOW and other operating weights (on paper) to keep the other operating costs (parking fees, airport handling, overflying fees, air traffic control, etc.) as low as possible, if you never use these maximum structural weights on your route network.
It's a trade off between operating costs and required capabilities (payload-range) of the aircraft.
On a twin, crossing an ocean, you're always one engine failure from a total emergency.
Interesting info, many thanks. So I assume JAL already reduced the TOW to 310'000 for the reasons you mentioned. when I flew on VP-BGU it operated BKK-SVO, a rather long leg but apparently still in the 310'000 TOW range.
So if you say it is a reduction on paper means the aircraft may physically be operated at a higher MTOW? So I conclude the reduced paper weight of 310'000 doesn't make VP-BGU a -300SR version.
Unfortunately I couldn't find their rates online, I assume it is expensive because my employer has full access to all data. Knowing what other online fleet lists charge such as airfleets.net, ATDB or CH-Aviation.ch, I wouldn't be surprised if it was a higher 4-digit figure. ACAS has a good range of data such as full aircraft history, maintenance data, hours, cycles, etc. What I found though is that they sometimes lag several months behind in updating its database. Others are much faster (CH Aviation e.g. is quite up to date).
imiakhtar From , joined Dec 1969, posts, RR: Reply 4, posted (1 year 5 months 4 weeks 1 day 1 hour ago) and read 2643 times:
Quoting Loran (Reply 3): So if you say it is a reduction on paper means the aircraft may physically be operated at a higher MTOW?
Most countries base their airport and transit fees on MTOW of the aircraft (US I believe base their fees off the Max Landing Weight). If you're not regularly utilising the MTOW, paying the higher fees is silly. Most BA A319s for example have a MTOW of 64t.