737-300 flap speed schedules

[silverhawk]

At less than 53 tonnes, there are the fixed speed schedules for flaps
flap 0 210 kts
flap 1 190
flap 5 180
flap 15 150
flap 25 140

i remember some sort of issue over the fixed speed for flap 10, any input please?

Ignoring the speed tape with it's info from fmc. Cheers

[Right Way Up]

Yes Flap10 requires 170 kts. So if you are asked to maintain 160 kts you must select Flap 15, which in turn requires gear down, unless you do not mind the gear warning horn blaring away continuously. Obviously not very efficient or neighbourly to fly this config. I used to ask for 170 kts to 5 miles!

[Centaurus]

At 53 tonnes or under, the original flap 5 manoeuvre block speed was 170 knots and Flap 10 was 160 knots. Then after the rudder problems the speeds were jacked up by 10 knots to cover cross-over speed control handling.

That's fine and I have no problem with that, except that maintaining Flap 10 and 170 knots on single engine during the conduct of a circling approach invariably meant lots and lots of thrust on the live engine. That extra 10 knots is hard to maintain under that configuration.

What has me tossed is why Boeing still require the additional 10 knots at those flap settings (Flap 5 and 10)when flying with one engine inoperative. If you get a rudder hard-over while on single engine you are history anyway - whether or not you are flying at 160,170 or 180 knots.

The chances of getting a rudder hard-over just as you happen to be on one engine, must be statistically insignicant (it ain't never gonna happen in your lifetime,mate!)

[silverhawk]

The mist clears, thanks

[Gary Lager]

Erm...aren't the chances (statistically speaking) of getting a rudder hardover the same whether you are single-engine or two-engine?

That's a bit like saying "those lottery numbers came up last week so the chances of them coming up this week are even less!"

Anyway, wouldn't a rudder hardover+engine failure only have a 50% chance of wiping you out...depending on which engine was failed?

What if you had the rudder hardover first, and then had the engine failure?


;)

[Centaurus]

You might fly several thousand hours on a 737 in a lifetime and never have an engine failure that ends up with a one engine inoperative approach. Therefore the risk of a rudder hard-over is a certain figure if you look at the hours flown on normal ops.

The chances, I would hazard a guess, at having a rudder hard-over therefore while carrying out perhaps the one and only in flight engine failure you will ever experience, is minus zilch - and I'll take my chances and use flap 5 and 170 knots. I am sure I will be shot down in flames on this point of view, but so what?

[Gary Lager]

But surely the chance of having an engine failure, a rudder failure and getting shot down in flames is even more remote...?

;)