B744 PW4056 hot start vs. RB211

[main_dog]

On the 747-200 RB211-524D4 as I recall the F/E used to monitor EGTs and %N3 to ensure the former did not overtake the latter (ie. more than 350˚ at 35%N3), as this was a reliable symptom of an impending hot start.

A very experienced instructor recently showed me how on the B744 RB211-524G you can do the same by noting that EGT shouldn't exceed approximately 250˚ at 10%N1, 270˚ at 11%N1 and 300˚ at 12%N1. This seems to work like a charm.

Does anyone have a similar rule of thumb for starting PW4056s? (And yes most of our "four hundreds" are manual start only)

MD

[barit1]

I should think that using core speed (N3 on R-R, N2 on PW or GE) instead of N1 reference would make the most sense. My reasoning is that during start, N1 is still dependent on windmilling speed. It might even be windmilling in reverse due to tailwind.

[Patty747400]

Try 1-2-4 for the PW 4056.

N1 10 %
EGT approx 200
N2 40 %

Should work fine in most cases.

[spannersatcx]

That very experienced instructor should know then that the egt v N3 relationship is the same on the G as it is on the D4, EGT <N3 x 10.

It would be difficult to monitor n3 and egt on the classic as the gauges are on different panels, N3 on FE's panel, EGT on pilots centre panel. We always have minimum of 2 on the flt deck when running engs, person in FE's seat calls N3 whilst person in the left seat monitors EGT.

From memory pilots panel has EPR, N1, EGT, FF.

PW on 744 no rule of thumb or relationship between EGT/N1/N2, if it's going hot you will know.:eek:

[main_dog]

Thanks Patty, I'll start with that.

Barit, I would have thought so too, but it works very well!

if it's going hot you will know.

Spanners, how will I know? Can you hear it like on the "roller"?

[spannersatcx]

That was the 'ticking' sound of the analogue guage on the classic that gave you an aural alert as well. The PW is quite a slow accelerating/egt rising eng, if you start them a lot then you should be able to see that the egt is increasing a lot faster and getting hotter quicker as long as you catch it before you reach the limit you're ok.