? for 737 pilots, doug?

[Timbuff10]

Hey guys, I work on the ramp and had a little incident tonight while pusing a 733 out of the gate. The Captain wanted us to push him out and then turn him so he is lined up on the taxiway that is perpindicular to the Jline we were pushing out of the gate on. I kinda got close to another plane and wasn't able to get him to where he wanted to be. It all worked out in the end though and the only damage was my ego a bit...

My question is, when you do an air start and the aircraft is not pointed into the wind does it matter? In my situation tonight the wind was about 5-10kts. Captains seem to like to be pointed into the wind and from what i hear, it is hard/impossible to start the other engine if it is not in the wind, any truth to this?

Can anyone shed some light on this topic?

Also, why would you as a captain want a ramper steering your plane all over the place?

Tim

 

[derg]

If you're doing an "air start", I presume that you mean he's using a 'huffer cart' or ground air unit to get the engnes started?

In any case, when you try to start with a strong tailwind, you'll run a big chance of reaching your maximum EGT limits for start.

A few years ago, we were in Tuscon and we couldn't get the engine started because it was "overtemping". We had the tug driver reconnect to the aircraft and point us into the wind, thus removing the tailwind.

Voila! It started just perfectly!

 

[Timbuff10]

Thanks for the reply Doug, yeah we were using the huffer cart. I figured there was something to it. When i brought it up to one of the career rampers, he said to screw what the pilot wants as far as turning him into the wind. Then he said something about how the pilot can just start taxiing with the one engine and then crank up the other on the run.

I imagine it would be sorta tough to make turns to the right with only a no1 engine running. I also doubt its very safe to be cranking up engines while you are taxiing and dodging other planes.

Anyway, thanks for the answer! Now when someone asks me why i turned the plane to the side i can come back with something slightly better than "well, the pilot requested it".

Tim

 

[derg]

A couple of other points about single-engine taxiing too: We single engine taxi quite a bit at Delta, but if you've got to make a large angled turn to exit the ramp, the captain's really going to have to "goose" the running engine to build momentum to make the turn. Unsecured items onthe ramp tend to be blown into "inconvenient" places cause damage.

But we accomplish some starts as we're taxiing out to the runway. Usually, the FO will do the "tops" (which is the starter switch on the overhead panel) and "bottoms" (which is the fuel control lever near the bottom of the throttle quadrant).

If the guy's got to use a huffer cart to start and then requests to have the aircraft pointed in a certain direction, you've gotta cover your butt and fulfill the request. When we kept overtemping during a tailwind start in Tuscon, the ramp had no interest in helping us reposition the aircraft into the wind because their shift was ending. So we had to sit out on the taxiway helpless and immoveable because they didn't understand the gravity of the situation.

 

[Mr_Creepy]

It's definitely important to point the aircraft in to the wind if possible, since many of those "huffers" are old, decrepit and seriously in need of maintenance. The power just isn't there.

At IAD, they used to give us these "Bottles" that would be just that. It looked like a big, iron, water cooler bottle, full of compressed air. They were good for about 1 3/4 starts. I say 3/4 because if you were the second start on the bottle you had a darn good chance of not getting enough air for a complete start. It got to the point that I was asked if I was getting a used bottle and ask them to go fill it up again at the compressor or get me another bottle.

You may ask why we need to do "external air starts" and well you should young man! Because APUs are often deferred for maintenance. They are abused and poorly understood little workhorses, and to make it worse, most aircraft have an external APU shut off switch which for some reason ramp rats can't keep their hands off of.

Whenever they get shut off this way without an complete procedure and cooldown they can get damaged. There are also several other mechanical things that can inhibit the APU, such as door operation.

APUs are wonderful thing, but I would teach my students that the APU is a luxury and not a necessity and don't ever count on having it!

 

[IrishSheepdog]

In our aircraft, sometimes starting with a tailwind not only can cause an overheat, but also can be forceful enough to keep the engine from spooling up properly. In that case, a trick is to do a battery start instead of a GPU start. The GPU puts out 28V, however during starting our two NiCad batteries combine their power to provide 48V for the start. This allows a faster spool up time. Then you can taxi out single engine and face into the wind to do a cross-generator start.

We often don't have the option of what direction to start, since we park the same direction always and start the number 2 engine prior to passenger boarding. But if the captain requests to be pointed a certain way, do it... it's important to the health of the aircraft.

 

[MikeD]

Doug,

I sometimes hear airliners calling ground to get clearance for a crossbleed start. Why would you guys start via that method? On our jet, the APU provides air to the ATS (Air Turbine Starter) valve for each engine; a crossbleed start would only be used in the case of the APU being inop, in which case a huffer would need to be used to start the #1 anyway. Is it the same for you guys? In our case, we'd never get as far as a crossbleed start since the plane would be Red X for the inop APU anyway.

 

[Mr_Creepy]

You are right MikeD - it's when the APU is inop. We get one going with the huffer and then get out a safe distance so we can spool the other up enough to get #2 going crossbleed.

 

[kellwolf]

[ QUOTE ]
Unsecured items onthe ramp tend to be blown into "inconvenient" places cause damage

[/ QUOTE ]

Like my eyes?

Air starts at MCO are kind of a non-event for me. Every once in a while we'll get one of ye ole 737-200s in with ANOTHER busted APU and have to do an airstart. However, I've never had a captain tell me to turn the plane since it is all done at the gate. Big long pneumatic hose going to the center of the a/c, ground power hooked in, start the air, start #2, start #1, turn off air, disconnect ground power, and CAREFULLY disconnect the air hose (we have to keep one shoulder against the fuselage in order to make absolutely sure we go nowhere near the spinning engine). After all that, we push 'em out and let 'em roll. Same applies for -300s and -700s. I've only had a captain cross bleed once, but that was b/c he was having bleed air issues from the APU and not a totally failed APU.