KLM 753 AMS-BON (TNCB Flamingo)

[cieloitaliano]

Anyone know why KLM 753 (an MD11 usually) Stays 'low' for it's transit over the southern UK?

Carrying plumbing supplies to the Caribbean doesn't count.

[HEATHROW DIRECTOR]

What do you mean by "low"?

[cieloitaliano]

It has transited UK airspace at 260 on some nights. It was at 300 last night which seems low for the MD11 which usually displays the attributes of a home sick angel.

[HEATHROW DIRECTOR]

Presumably you mean westbound? Eastbound they often start descent in UK airspace. Could be because of other traffic which you couldn't see?

[cieloitaliano]

The 'midnight express' from AMS to the Caribbean is indeed westbound. Only other things around at this time that may cause restrictions are the usual insomniac's:Tommy's travel, etc.
These however are usually minding their own business.

It's track is usually Thames estuary Lands Endish but it does seem to stay below 300 the times I've seen it. Infact, it passed over Swanwick at 260 this week.

[HEATHROW DIRECTOR]

Hmmm... interesting. Maybe someone else will come up with a clue.

[22/04]

Not sure whether MD-11s may be unable to climb to final cruise until some fuel burn reduces the weight.

[pax britanica]

Making a guess as only pax here :-

Assuming flight leaves AMS late at night it will arrive in Bonaire in early hours of morning. In Caribbean some diversion airports may not be open all night and so may have to carry decent amout of diversion fuel-maybe they plan it to continue direct to Guayquil (next segment) if Bonaire closed.
So it is carrying a decent fuel load for a start.

Second thing is Bonaire is Caribbean island, everything is imported except sand so its probably maxed out on Cargo.

Take one and two togehter and its a heavy aircraft.

Late at might it can probably get track direct from somewhere off Dutch coast direct to SAMPTON on the normal route for N Europe to Caribbean aircraft but maybe shaved 50track miles off a daytime route as theres not much traffic and doesnt have to follow airways.

So guessing Southampton is around 250 miles from AMS why struggle to get to FL350 to avoid all the numerous N-S route conflicts across the UK which are not really there in middle of night when you can climb gently and take your time to achieve your Atlantic crossing level

Make any sense ?
PB

[cieloitaliano]

Very comprehensive, informed, reasoning PAX.
Staying low for the stated reasons does make sense but how would that compute with fuel burn/altitude parameters?

Any MD11 drivers undergoing decompression anywhere?

[Middleagedman]

KLM753 usually cruises over the UK at FL300 or 320. Flying at 260 may be due to weight, but my guess is that it would choose to stay lower to avoid strong headwinds, which can sometimes be 40-50 kts stronger a few thousand feet higher. The time saved could outweigh the extra fuel burn, but it doesn't happen often.

[MISSED APCH]

as read above, i agree with some and dont'

in the first place, bonaire doesnt close at night, curacao <50nm away doesnt close at night, aruba 100 miles away does, but for emergency's it will allow to land.
klm doesnt need to carry too much extra fuel for diversions, venezuela is very close by, and its just another 30minutes flying. and as a matter of fact, it will overfly the northern antilles before it gets to bonaire and could land there if its a weather situation. for weather concerns, all the above mentioned airports likely be in the same weather.

another thing i didnt agree with was, cargo??? who brings cargo from europe to the caribbean, when usa is right there?
there is minimal cargo from europe to bonaire.
most cargo will go from south america via curacao to the netherlands. and those are mostly flowers, and steak. yumm

anyways,
i was told from an old timer klm DC10 cap, that klm doesnt fly the shortest routes (great circle). they will actually plan a flight according to the shortest time. looking at forcasted winds, and turn that into flight time, giving that last reply a fair chance thats whats happening.

i have seen that md11 fly a couple of times from bonaire to aruba climbing to fl160. which i can only justify with tailwind, good idle descend, fuel saving scheme.

but this is all speculations and constructive criticism.
so hope it helps !:ok:

[cieloitaliano]

Er, as I write now from the South West UK @ 2330 she is going past at 300.....2350 @ 29950 exiting UK Airspace.
Still low, IMO, for a thin air hungry tri-jet.

[airsmiles]

Perhaps it's more to do with keeping a lower level pending clarity of its assigned oceanic crossing level?

[pax britanica]

Hi Missed APch
Very interesting and courteously worded message. I am not familiar with the islands in the southern Caribbean but do know something about the more northerly ones where SXM and San Juan apart they are not great and hence my wondering about possible night closures.
Freight of course it is a good point you make and so much would come from US or in the case of the Dutch islands from Venezuela as its so close to them. Perhaps the special status of the ABC group viz a viz Netherlands makes it worth carrying varying amounts of freight from AMS perhaps varying the weight of the aircraft accordingly.
Anyway yours was a very interesting post I thought. I think most airlines use what you describe as a practical route compared to great circle. I think the name is ’minimum time path’ or similar and certainly on this side of the Atlantic any aircraft heading south west from UK can face some of the strongest headwinds and possibly quite varied routes across the Atlantic which again might account for different altitudes different days.
As a general comment it seems there are very few after midnight departures heading west from Europe –it seems very late even for freighters any one know why it leaves so late and no doubt has an ungodly arrival time.
PB

[cieloitaliano]

This morning @ 0045 Abeam Swanwick at 29975. 491 kts (591mph).
It would appear that optimum speed is being maintained at the minimum altitude possible.

Could their bean counters do my tax return please?