Both X-FEED on Seneca II

I've asked the following question to NewPiper Inc.

Sent: Tuesday, February 08, 2005 7:24 AM
To: Flynn, Kathy L.
Subject: PA34 200T question

Dear Mrs / Ms Flynn
I've called the italian dealer you gave my the number of.
They made me talk with the dirigent who answered my question in the way
I'll report

Since I'm not fully satisfied by his answer I would like also your opinion.

In the P.O.H. of the PA-34-200T, Seneca II I'm flying with, Section 7 -
Description and operation, there is a NOTE which reports:
"Do not operate with both selectors on "X-FEED.""
Page 7-13 Issued August 23, 1976 Revised March 11, 1977

If such a note is present I suppose that something dangerous may happen
if the prescription wouldn't be followed .

It is straightforward that operating the airplane with both engines in
x-feed is meaningless,
but I would like to know which could be the consequence of operating
both engines on X-FEED on the ground, other than wasting some of the
returned fuel if the tanks are full.

The italian dealer answered:
"I don't know the answer but I think if you use both engines in x-feed
they will stop for lack of fuel. In any case you don't need to worry
about the x-feed pipeline integrity. It is checked yearly by mechanics,
and also you'll never use it in your life."

This was all his answer and it seems a little too generic to me and,
maybe I'm wrong, I'm not sure He's aware of the precise technical
consequence of the both engines x-feed operation.

Since I'm going to fly as instructor on this plane I would like to know
in deep detail all the consequences of the possible wrong actions.
Your help would be really useful to me.

Thank you for your attention,
Silvio Mecucci

Piper answer was:

I our technical support reviewed your message and responded with following
reply:

* All aircraft per certification must be operated using the most current
Pilot's Operating Handbook for their aircraft.
* The New Piper Aircraft, Inc. recommends the aircraft to be operated per
the approved current manual for the aircraft.
* The New Piper Aircraft, Inc. will not speculate on what may happen if the
aircraft is not operated per the most current correct POH.

Thank you,
Kathy Flynn
THE NEW PIPER AIRCAFT, INC.

And this was my last reply...

Dear Mrs/Ms Flynn,
I do agree with all the point you made and for sure I will operate the
aircraft only according to the manual.
Having made this last point certain, what I would like to know is the reason
why Piper put that note in the manual.
This doesn't mean I don't want to follow it....

The problem is that if I, as a flight instructor, say to someone "Never use
it in this way." and that someone asks me "Why ?"
I should be able to answer him something more complete than "Since this is
what the manual says.".
That's the reason why I've asked You a support in this.

I can assure You that nothing of what You will write in the email (I hope
you will answer me again) has a legal
value here in Italy (yet), so could you please tell me the reason that note
is present in the P.O.H. ?

Silvio Mecucci

No answer since then...
Can anybody help me, or should I unassemble my Seneca II to get an answer ?

Thank You all,
Silvio Mecucci

"Silvio Mecucci" wrote in message
om...
I've asked the following question to NewPiper Inc.


You are simply wasting your time. Nobody is going to care about how you can
contort your airplane into an un-airworthy state. Be more concerned about
learning the proper way to operate the fuel system.

Follow the POH.

Karl

Isn't that what he is trying to do?
I don't find his request extraordinary.
I find it perfectly reasonable to learn the consequences of an
inadvertant selector setting.
This is like turning the boost pump on while the engine driven pump on a
Bonanza is operating normally. It says don't do it, but it doesn't tell
you why.

kage wrote:
You are simply wasting your time. Nobody is going to care about how you can
contort your airplane into an un-airworthy state. Be more concerned about
learning the proper way to operate the fuel system.
Follow the POH.

Silvio Mecucci wrote:
The problem is that if I, as a flight instructor, say to someone
"Never use
it in this way." and that someone asks me "Why ?"

And the reply is, because if you do that, then you are being a test
pilot.
At any rate, I would certainly not be willing to find out if it works.
But if you really need to know, can't you just look at the fuel system
diagram in the POH?

Nobody is going to care about how you can
contort your airplane into an un-airworthy state. Be more concerned about
learning the proper way to operate the fuel system.

"VFR not reccomended"

This answer is exactly why people no longer understand the world
around them. I run into this mostly with computers ("Just tell me
what button to push") and the consequence is that
1: they don't really learn what button to push.
2: they have no idea what happens when they push it.

and as a further consequence, nobody who works in tech support will
tell you what happens when you push it.

Jose
--
Nothing is more powerful than a commercial interest.
for Email, make the obvious change in the address.

"kage" wrote in message ...
"Silvio Mecucci" wrote in message
om...
I've asked the following question to NewPiper Inc.


You are simply wasting your time. Nobody is going to care about how you can
contort your airplane into an un-airworthy state. Be more concerned about
learning the proper way to operate the fuel system.

Follow the POH.

Karl

You and NewPiper seem to be on the same line CYA

I never said I want to operate the plane in ways different from those
reported in the POH. I just would like to know WHY the POH is that
way.
For those who know exactly how the fuel system works on the Seneca II
it shouldn't take that much time to answer my question.
POH like all the uman products can be wrong, even if I'm sure this is
not the case. Knowing how things works, beside "turn it on or off",
sometimes is useful.

Imagine you are a FI and your student asks you why you should not test
both X-FEED at the same time durign taxying. What are you gonna answer
him ? "Because it is written in the POH." ?! If your student is a good
one He would not be satisfied by this answer since it is an answer it
could find himself.

Thank you anyway...
Silvio

Imagine you are a FI and your student asks you why you should not test
both X-FEED at the same time durign taxying. What are you gonna answer
him ? "Because it is written in the POH." ?! If your student is a good
one He would not be satisfied by this answer since it is an answer it
could find himself.

Thank you anyway...
Silvio

Imagine you are a FI and your student asks you why you should not test
THE LANDING GEAR time durign taxying. What are you gonna answer
him ? "Because it is written in the POH." ?! If your student is a good
one He would not be satisfied by this answer since it is an answer it
could find himself.

Best,
Karl

And the reply is, because if you do that, then you are being a test
pilot.
Really nice answer !
I'll use it meanwhile...

At any rate, I would certainly not be willing to find out if it works.
But if you really need to know, can't you just look at the fuel system
diagram in the POH?

That's what I did. In the diagram, as it should be, there is no
connection between the two pipelines. So, as far as the diagram
reports, no problem should arise.
Also.. since in short taxying like those in small fields you don't
have enough time to test both X-FEED pipelines each at a time, I heard
is a common beheaviour to test both at the same time.

I am going to actually look at the valves operated by selectors.
Maybe the two valves are mounted nearby and there is no enough room
for them to operate properly at the same time... it's just a
supposition.
I'll tell you about.

Silvio

"kage" wrote in message ...
"Silvio Mecucci" wrote in message
om...
I've asked the following question to NewPiper Inc.


You are simply wasting your time. Nobody is going to care about how you can
contort your airplane into an un-airworthy state. Be more concerned about
learning the proper way to operate the fuel system.

Follow the POH.

Karl

Just an example about why to ask such a question...

You take off with a PA19 (L18C), full tank(s), no special AC, after
leaving the ATZ you start a continuos turn with 30° bank. After 20
minutes (maybe less) your engine stops. As far as I know there is
nothing reported about this in the POH. And continuous turns are not
prohibited manouvers for a PA19.
In this case you follow the POH, performs a normal, even if unusual,
flight, and you get into trouble just because you don't know how one
of the simplest aircraft fuel system works.

Silvio

I'm sorry but I can't understand your observation:

First.
What you exactly mean by "test the landing gear" ?! What you want to
test ?
The green lights, the actuator, the switch, or what ?
But testing the X-FEED selector is very specific on the PA34.

Second.
I've never seen something like "Don't *test* the landing gear during
taxying."
in any P.O.H. I've read.
But I did see "Check the operation of the fuel management controls by
moving each fuel
selector to CROSSFED for a short time, while the other selector is in
the ON position."
(PA-34-200T P.O.H. Section 4 Normal Procedures 4.23-Taxiing)

Also the "short time" terms are questionable. Do you remember how long
it took to stop the
engine when your FI/CRI simulated an engine failure cutting your fuel
? And the engine was
(hopefully) at cruise power. How long would it take to use all the
fuel in the whole main
pipeline from the same side and let the X-tank fuel feed the engine ?
Making this test for 3-4-5 seconds is meaningless.


Third.
Should a student ask such a question every FI will know the answer:
"Because the safety valve may not work and your landing gear may
retract
while on the ground."
But I couldn't find any answer to my question yet.

Fourth.
The answer every FI should know (to your student's specific question)
is usually
reported in the P.O.H.s (At least in that of the PA23 Atzec).
But I couldn't find anything similar for the fuel selectors yet.
Maybe someone who reads the P.O.H. more carefully than me can
answer...


Silvio

"kage" wrote in message ...

Imagine you are a FI and your student asks you why you should not test
both X-FEED at the same time durign taxying. What are you gonna answer
him ? "Because it is written in the POH." ?! If your student is a good
one He would not be satisfied by this answer since it is an answer it
could find himself.

Thank you anyway...
Silvio

Imagine you are a FI and your student asks you why you should not test
THE LANDING GEAR time durign taxying. What are you gonna answer
him ? "Because it is written in the POH." ?! If your student is a good
one He would not be satisfied by this answer since it is an answer it
could find himself.

Best,
Karl