BAE146/AVRO RJ - Hot & High Take off performance

[George Tower]

Just wondering if any guys/girls that drive these machines can give me some kind of indication as to what they're like in hot and high conditions.

Any chance of flying a 700nm sector, at MTOW from the follwing:

Airfield1 - Elevation 2500ftAMSL, RWY length1200M, OAT35degreesC

Airfield2 - Eleveation 5500ftAMSL, RWY length 1800m, OAT 30degreesC

Many thanks

GT

[One Step Beyond]

No chance of an MTOW take-off for your examples.

You start getting weight restricted above about 20C at somewhere like LCY, which is 1300m and at SL. At somewhere about 1600m and also at SL, above about 30C will cause problems. Obviously it also depends on whether its a Field Restriction/Obstacle restriction/etc but these are good ball-park figures.

In terms of the take-off performance for a given weight, the sector length is irrelevant, however your example is academic anyway as a 700nm flight started at MTOW will leave you above MLW:
MTOW = 42.2t (146-200) / 44.2t (-300)
700nm flight = approx 4.5t burn + 200kg taxi
=> But MLW's are 36.7t (-200) and 37.6 (-300) so you would be above weight.

In fact, on your given 700nm sector flight, you would never reach MTOW anyway. eg
DOW: 24.5t (-200)
Block fuel: 7.0t
Max likely pax load: 8t (84kg x 95 pax)
= 39.5t TOW

[George Tower]

Hi One Step Beyond

Thanks for your reply. I guess I sound like a bit of a twit as the biggest thing I have flown myself is a Seneca. However it was asked more out of academic interest.

I remember being somewhat incredulous a few years back when I heard that South African Airlink were operating the Embraer135 from Cape Town to Windhoek Eros (now closed to commercial traffic). Windhoek Eros is 5500ftAMSL, RWY length 1800m, with summer time temps regularly around the 30C mark. Apparently take off performance wasn't a problem neither was there a weight penalty. I do believe the ERJ135s operated by Airlink were fitted with ERJ145 engines which according Embraer would provide an extra 1500lbs thrust. Still I would have thought the 146/RJ would have been able to match and better the ERJ in the area of STOL performance.

[safetypee]

George, the basic rule of thumb for 146/RJ operations is to use a ‘square’ runway i.e. as long as it is high.
Thus there were operations from Paro (Bhutan) at 7000 ft altitude to Dhaka, thence to Bangkok. Also from Aspen (circa 6000 ft) direct to the US West coast or Chicago.
THY uses their RJ100s at TatVan? (Lake Van, 5000ft, +25C? 24 flap take off) direct to Ankara with a full 100 pax load.

The 146/RJ was built to handle difficult airfields and should match or have better airfield performance than any other RJ, particularly when hot and high. The Avro RJ has the better performance with a higher flat rated thrust engine than the 146.

[George Tower]

Now im confused......

Lets say I want to fly an AVRO RJ70, full pax, plus fuel for 700nm with IFR reserves, from an airfield 2500'AMSL RWY 3937' ISA+20 is it possible?

And again is it possible to fly the same a/c, full pax, 700nm, from an airfield 5500'AMSL RWY 5900' ISA+25?

Sorry to trouble you blokes. I wish there was a website for sad b@stards like me to download flightmanuals. Thanks for your input.

[ElNino]

Never flown the RJ, but I doubt a 146 could. ISA+20 at 2500AMSL being about 30C would be too hot I would say off such a short runway.
The 146 is flat rated to only 15C, the RJ is higher, but not sure what the figure is, so it should be a bit more spritely. Also, as 146/RJ's all share the same engine, regardless of variant, the 70 should perform that bit better, being a bit lighter.
The ALF engines run out of steam very quickly as the temperature and/or altitude rises, so, while they can get good loads off limited runways, you can't expect miracles.

[Capt Claret]

George, with the information I have at hand:

Off a 2400m rwy @ 1800' AMSL

-100 @ 50 degrees C 38290 kg Flap 18
-200 @ 26 degrees C 42880 kg Flap 24
-300 (507 engines) @ 38 degrees C 44370 kg Flap 24

Using a 300 as an example, a 700nm sector would require a nil wind flight fuel of 4200 + 10% variable reserve + fixed reserve of 950 = required minimum fuel load of 5570 kg.

Assuming 87 pax (our config) @ 100kg including luggage + 500kg freight, you'd end up with:

EZFW of 35299kg
MLW 39235
+ FBO 4200
= MRW 43435 this is less than MTOW, ie LDg Wt limited. You could carry a fuel load of 8136 kg, 2566 kg margin fuel.

I'll check perf figures for your desired rwy lengths when I get into the 100 this afternoon.

[False Capture]

The Honeywell LF 507 engines fitted to the Avro RJ seies are flat rated at 7000lb to 23.5degreesC. The cancelled RJX with its Honeywell AS977 engines were flat rated at 7000lb to 35degreesC.

The AS977 engines were 15% more efficient resulting in a 17% increase in range. The RJX would have been a better performer in the hot&high scenarios discussed here.

Best bit about the RJX ...... dual FADEC!:ok:

[Moogie]

I know when i was on the 146(300) 2 years ago operating from LCY to DUB (only 1 hour FT) in the summer when we had OAT's over 30C, we were severly restricted weight wise, restricting pax loads to below 80. Once i even had to go from LCY to Dub via Stansted to fuel, as we were too runway TOW restricted to take required pax and fuel to Dublin with 35C temperatures. But that was a uniquely LCY phenomena.
Not withstanding that though, the 146 was a bit wheezy in terms of performance.
I remember several times struggling to make FL190 in light icing on flights from Dublin to the UK and back.
Of course thats all forgotten now that i'm on the A320 with no performance considerations to consider!!!
Still miss the 146 though:{

[WHBM]

Moogie:

I was regularly paxing EI LCY-DUB then, and on a hot afternoon checkin would draw a line at I guess about 80 pax until the incoming aircraft arrived and the skipper did the calcs on how many could be taken.

About 20 pax all milling round the desk. Now if you were the one who was pleasant and polite throughout, and in your office suit, upgrade at the end was almost certain !

Not a problem now for Cityjet on the route I think as they use -200, not -300.

Was given to believe the key problem at LCY is not runway length but the obstacles on climbout in the event of an engine failure.

[Moogie]

A bit of both. I know that Obstacle clearance was responsible for the 6 degree glideslope on rw 28/10, but RTOW restrictions were both field and obstacle based. Cant remember exact factors for both since our 146 RTOW performance books have long vanished. EI had its own performance figures which were generally far more conservitive and limiting than that found in the AFM, so in theory we probably could have taken a few more pax.
Best ask a current City Jet lad who would be far more in the know than i am.
I'm currently on the 'Bus' and have forgotten a lot of the 146 performance stuff.:ugh:

oh and yes, i do remember playing with the figures to try to get as many of the pax out as possible. Sometimes we were juggling down to kilos!!!

[ElNino]

Moogie, you sound a little sad to be off the 146. Fear not, there would be no shortage of local 146 drivers willing to jump at your 320 job should you wish to pollywaffle some more!


WHBM: Cityjet may use the -200 to LCY, but if its warm enough, the problems still occur. Above about 20C, a full pax load of 93 starts looking dodgy.
You are correct in saying that LCY is obstacle limited (off 28 anyway, I can't remember off 10 what the limiting factors are). It only becomes field length limited in the event of a tailwind.

[WHBM]

I've lived next to LCY for a long time (actually for longer than the airport has been there).

Two of the limiting factors must be the bridges over the docks at either end of the runway, higher than the runway elevation. The irony is both these bridges are new, and have been built since the airport was established. That at the eastern end is only about 5 years old; it was rebuilt with the road deck higher than the old one :rolleyes: . Its predecessor was a lifting bridge and the glidescope must have allowed for it being raised (which nowadays is required about once a year !). The swing bridge at the western end doesn't have this lifting problem but was built for some reason with a large elevated control room which again must determine the glidescope on 10 approach.

There's also a large tall warehouse (the white one) at the western end which may affect things. It has been abandoned for at least 20 years.

Only very occasionally do large ships still come into the docks (for example Warships come up to the Excel exhibition centre for the military trade show), and I believe as they sail in past the runway they affect the ILS glidescope.

Overall a lack of joined-up planning I'm afraid. Both bridges could have been designed differently.

I'm just wondering, mentioning LCY 146 MTOW restrictions, how others manage, such as Swiss to Zurich (half as far again as DUB), who use -300s, and in the past Malmo Aviation worked to Malmo, well over double the distance of DUB.

[Moogie]

We had our own airline performance figures which were a lot more limiting & restricting than the aircraft flight manual figures produced by Avro. Just ta be safe!
Not sure if Swiss used those produced by Avro, in which case thay could haul a lot more weight out of there. I know we definitely had narrower bands on the weight and balance/COG loadsheet, and also restricted out structural TOW to 41750kg (although this could have been done to save landing fees!):ok:

thats 41750kg on our -300\'s:ok:

[alf5071h]

Just to update some of the previous info from WHBM about LCY. The dominant approach obstacle on RW10 is Canary Warf, although others mentioned such as the ‘protected’ warehouse and heritage cranes (some moved), will also restrict the takeoff fight path. The Canary Warf problem was solved with a combination of the 5.5deg glidepath and claiming a less restrictive obstacle free zone by use of a Cat2 ‘quality’ glidepath beam (although not certificated for use) with PAPI; so do not go low on the PAPIs.
The requirement for a steep approach on RW 28 was the need to clear the planned new bridge - the East London River Crossing; this has not been built. The dominant obstacles would have been a London Bus and the bridge road lights. I assume that the 5.5. deg glidepath is retained for noise reasons.

ElNino please don’t even think of taking off in a tail wind, apart from the problem of noise (even in a 146) you need all of the safety margins on your side at LCY.

Moogie I would be surprised if your perf figures differed significantly from the AFM; the last that I saw originated from a common 3rd party provider based on the AFM. Don’t forget that Swiss operate the heavier RJs and that some of the RJ100 have flap33 takeoff clearance. The 146’s have a range of wt limits lower than the RJ for many reasons such as commercial as you indicate or structure depending on build standard.

The 146/RJ is a great performer at LCY and at any hot and high airfields in comparison with other aircraft with similar load range capabilities.

[WHBM]

The requirement for a steep approach on RW 28 was the need to clear the planned new bridge - the East London River Crossing; this has not been built.
The bridge is winding its way through the planning process. Expect construction to start in a few years.

Here are links to show its location and the appearence of what you will be flying over. Note the approach to 28 does not pass directly over the high point of the bridge mid-river but over the south shore approach.

Map :
http://www.tfl.gov.uk/tfl/downloads/pdf/thames-gateway-bridge/tgb-alignmentmap-0408.pdf

Picture:
http://www.tfl.gov.uk/tfl/thames-gateway/tgw-bridge/tgb-about.shtml

[ElNino]

please don’t even think of taking off in a tail wind

Err, no plans to try that. My point was that the book gives figures for it and the limiting factor is the field length. Just to reinforce the point that it's the obstacles and not the runway length that are the problem at LCY.

[George Tower]

Hi guys,

Just revisiting a thread I started a good long while ago - just wondering if there is any one out there that has a spare Flight Manual for the Avro RJ. I have tried the official BAE channels and so far it is proving hard to get hold of.

Rgds

GT