BN2A-27 Tip Tank Procedures

[Ixixly]

Hi All,

Just started working with an Islander equipped with Tip Tanks, it's new to the company and we don't have anyone around with any real experience working with the Tip Tank Variety but have heard they can be a real pain in the ass. As I understand it we have one with the older Manual System as opposed to the newer ones which have an Automatic Option.

The Flight Manual is the correct one but really only describes the Auto System and not the Manual one. The Placards around the Aircraft tell you to "Fill First, Use Last" which seems a bit counter-intuitive to myself and others as it would be a real shame to go and select them when your Mains are close to empty only to find the damned Pumps won't work for some reason! Also, what if you only required Mains Fuel and not Tip Tanks, would you still fill the Tips first before putting anything in the Mains?

Someone has mentioned to me that this is partially due to structural reasons that you use them last but I can't see how they are that much different to the Non-tip models structurally except for obviously the slightly larger wing span to encompass the tip tanks.

Can those who have used them in past perhaps describe the rules of thumb that they used and any pitfalls to watch out for? Also the actual panel at the top middle is rather vague in its operation, there are 3 switches, the outers are labelled "Mains/Tips" so I'm guessing this means that if I select Tips then it should start pumping from Tips to Mains, so it's more of an On/Off switch to transfer from Tips to Mains and then the single middle switch has 4 sets of labels, first one says "Main, On/Off" and the other side has "Tips, Bright/Dim" and then there are 4 Green Lights as well.

We can't do too much fiddling at the moment on the ground as the Aircraft has just arrived and requires some maintenance before getting airborne but I'm just trying to get ahead in terms of writing up Operating Procedures.

Thanks for all who can help!

[Me_3]

You are getting the two tip-tank systems confused.

If you have an aircraft that has the "Tips / Mains" switches, there is no pumps that transfer fuel from the tips to the mains. that switch simply actuates a valve out in the wing that changes the fuel feed from either the tips or mains. There is no pumping between tanks. Hence the placards instructing which tanks to use first. If you only require a limited amount of fuel, only put that amount in using the filling procedure specified in the manual.
The fuel selector for port/starboard is exactly that, the switches define which tank is used.

The bright/dim switch is simply there to dim the lights for the selector panel so you don't have two bright green lights in your face when operating at night.

The other system (which you don't have by the sounds of it) uses pumps to transfer fuel from your tips to your mains, which means you let your mains drop to 1/2 tank or a point you are happy with, then transfer fuel across as needed (or use the automatic system which can be a bit touchy)

Joys of BN2 islanders.. no two machines are alike...
Out of interest, whats the rego? Just wondering if I know the machine..(pm me if you like)

[Car RAMROD]

Joys of BN2 islanders.. no two machines are alike...

Except for their bone jarring vibration and ear damaging loudness!

PM me the rego too if you like, know some of the ones on the market...

[RadioSaigon]

Couldn't agree more -Me 3 is on the numbers. It's quite a few years since I last flew one, but one wee trick you may find useful... if she has the usual Islander (Narco?) stack in her, select one of your VHF Nav boxes to the headset and knock the squelch off. Then select your tip-tanks one at a time. You should be able to "listen" to the valve making its way across to your selection. You should hear a definite change in the static pattern you are listening to, which of course, ends when the valve selection completes!

On another note... If memory serves, the "fill first, use last" caveat is pretty common on tip-tanks. Same on Chickory Stick 300's with tips and 310's also!

PS: The tip-tank BN2's climb like a homesick angel, compared to those without! Enjoy!!! Fantastic wee machines to fly. ;-)

[Me_3]

hen select your tip-tanks one at a time. You should be able to "listen" to the valve making its way across to your selection. You should hear a definite change in the static pattern you are listening to, which of course, ends when the valve selection completes!

And if the valve doesn't select correctly, you will hear the radio very clear on one side. ;)

There is nothing complex about the BN2 systems, the biggest catch is people getting confused between the different models. carby/non-carby, different fuel systems, different instrument layouts..

If the pilots pay attention to which they are flying, no problems... just keep there feet off the brakes when taxiing.. they get destroyed VERY quickly when this happens..

[RadioSaigon]

just keep their feet off the brakes when taxiing...

Yep, and avoid taxiing thru puddles after landing. Cold water thrashes hot brake-pads.

Always do a dead-cut check before shutdown -only takes a sec- then pull your props thru to vertical. It's a truly miserable experience walking into a horizontal blade... the second time.

Keep a rag under your seat. Wipe the cowls and gear legs regularly.

You'll figure it out ;-)

[Pinky the pilot]

It's a truly miserable experience walking into a horizontal blade... the second time.


Knew a PNG National who did that!:ooh: Hearing him swear in ples tok and PNG Pigin, sometimes intermixed was er, how shall we say....an experience!:eek:

[Ixixly]

Haha, yeah, I've been flying the Islander for a little while now, definitely learnt about the props!! Always through to Vertical now except for the end of day to stop water pooling, very frustrating when I get the windows all squeaky clean for the pax to start up and have water come spraying out of them!

I usually now have taken to using my Fuel Strain Samples and using them to help clean the oil off the darned things, for such a greased up aircraft you'd think she'd fly a bit faster?!

And Definitely looking forward to experiencing what the extra bit of wingspan feels like, was wondering about that and have had mixed responses on what it does.

Just received a supplement explaining the system that I've been trying to track down so that solves the problem nicely but thanks for the advice everyone.

[Car RAMROD]

It is a bit harder to judge tip clearances on the ground if you have a model with the tip tanks, so be a little more careful with that. If you have shadows, they help, but are by no means any guarantee :ok:

I love islander induced cuts and bruises and oil stains!

[Capt Fathom]

Yep, and avoid taxiing thru puddles after landing. Cold water thrashes hot brake-pads.

Is this perculiar to the Islander? Or just another old wives' tale?

What happens when you land in the rain? :ugh:

[Tinstaafl]

Keeping fuel outboard for as long as possible helps relieve wing bendining loads at the wing root. The extra wingspan gives the wing more leverage to stress the wing root so keeping fuel in the outboards helps counter that.

[MakeItHappenCaptain]

Always do a dead-cut check before shutdown -only takes a sec- then pull your props thru to vertical. It's a truly miserable experience walking into a horizontal blade... the second time.

Have a mate who relayed the story of a rampy in PNG who was bolting under the wing and skewered himself on the pitot tube....through the eye.:ooh:

What happens when you land in the rain?

The water is already on the part and constantly being "applied", similar to the water injection cooling used in truck racing. Think of it like driving in the rain versus throwing a bucket of water through your wheel onto the disc after a big drive down a mountain range. Would you do that?:E

Applies to all types, however the Bongo is susceptible to high brake temps due to the weight, heavy use on short strips and the tendancy of pilots (as mentioned already) to ride the brakes.:=

Ps. Tinstaafl has it in one. Many aircraft, such as Cherokee Sixes use this pattern of fuel usage to increase the zero fuel weight. Think of the stress like the wing spar is a bis lever pivoting on the main gear mounts.

Pps. Watch that pitot heat, very powerful and if you forget to remove it will fry the cover off in less than a minute.

[rutan around]

The tip-tank BN2's climb like a homesick angel, compared to those without!

If the BN2 behaves the same as a C210 with tip tanks there a few other benefits you will enjoy. For a given weight they have better STOL performance. Also for long trips it really pays off to cruise a few thousand feet higher than you normally would because the speed is higher than non tip models especially when hot and heavy.

Flying high is quieter (a good thing in a BN2) cooler, smoother and gives you greater range. The down side is they're a few knots slower (2-4) down low.

[aussie_hawk]

One thing I found when flying a Bongo with the selectable tips was to never run the tip tanks dry. If you did there was a tendency to get pretty bad surging and the possibility of crud blocking up the fuel lines, plus not good if they are the bladder type.

We had the policy of having our fixed reserve in the tips as the minimum.