PA-28 door

[G-ALAN]

I'm curious as to why the door on the pa-28 warrior is on the right hand side of the aircraft? Why isn't there another one on the left? Surely common sense says put the door on the left hand side or even have one on both sides. It's a little annoying having to climb over the right hand seat when entering or leaving the aircraft.

[Rainboe]

So when the pilot is at the controls, how would the passengers get in? Very often you change occupants whilst a pilot is at the controls. There is significant expense strengthening the fuselage for a door on either side. For economy's sake, sometimes it´s cheaper to keep it simple.

[Donalk]

The PA 28 fuselage is a stressed skin design which means that the aircraft exterior is designed to bear all or some of the loads imposed on it. The more holes you cut into this design (essentially a semi monocoque construction) the more you weaken the load bearing ability of the structure.

As Rainboe has already pointed out it makes more sense to include the only door on the right from an operational perspective. I'm sure it was not structurally motivated.

[G-ALAN]

Thanks guys, that makes sense. I keep forgetting these things are used for commercial and charter work where pax are getting on and off.

[axl76fg]

i'd like to know if possible the location and the names of the aerials on PA28R 200..thanks

[Tinstaafl]

Antenna types, sizes & locations varies a lot. It all depends on what equipment has been fitted and where was convenient to access during fitting. Can be on the roof or belly or fin or underside of the wing. Antenna size reduces as the frequencies to be used increase.

Typical ones include:

VHF communication: something like a whip or blade antenna about a foot long

VHF navigation: a horizontal 'V' shaped antenna with the arms of the 'V' about the same lenth as a VHF comm (makes sense - the frequency ranges are similar). May be combined with the VHF com.

Glideslope: a pair of small horizontal 'blades' or a 'V'

DME: A small blade antenna

ELT: A whip about a foot long.

ADF: An oval or rectangular blister about 6" long + possibly longish horizontal rod (a foot or two in length) or wire if separate loop & sense aerials.

Transponder: A small blade or whip about the same size as the DME.

GPS: A small blister about 4" long. Often teardrop shaped.

HF communication: A long wire. Usually from the roof of the cockpit to the top of the fin and then to a wingtip. Easiest place to find the room for the length needed.

[happybiker]

Hi axl76fg

A long forgotten publication by the CAA may help you with your question on aerial locations.

http://www.caa.co.uk/docs/33/CAP457.pdf

[Genghis the Engineer]

The PA 28 fuselage is a stressed skin design which means that the aircraft exterior is designed to bear all or some of the loads imposed on it. The more holes you cut into this design (essentially a semi monocoque construction) the more you weaken the load bearing ability of the structure.

As Rainboe has already pointed out it makes more sense to include the only door on the right from an operational perspective. I'm sure it was not structurally motivated.

I've heard both of those arguments before, and frankly I think that they're complete cobblers.

From an engineering perspective, there is no substantial weight or strength penalty in fitting two doors. If there was, the same absurd "design solution" would be in many other aeroplanes or, for that matter, cars.

Also, having flown a lot of hours in PA28s I have never found it an operational advantage - especially when I'd really get passengers strapped in, do a last walk around the aircraft to confirm that everything is secure, chocks out and the like, then finally strap myself in and start up - in short what I do in every other type that I fly. Fast running changes are a rare, and usually foolhardy, thing to do in a small aeroplane: my passengers need a safety briefing, and I want to check they've not dropped anything just outside the aeroplane - all of this is best done with the engine off and usually with me outside the aeroplane at some point.

My best guess is that it was a cost saving measure in the 1960s, and since everybody got used to it, Piper have never gone to the cost and effort of changing the design.

G

[Jofm5]

Interesting thoughts on this one.

One observation I would make from currently learning on the cherokee is that it forces you to walk round the plane a couple of times when performing the pre-flight which may help you spot anything out of the ordinary.

For example if you were sloppy with your pre-flight and there was a door on the left you would not have to circle the aircraft to check the stall warning works (as you could just reach in to switch on the master switch) and likewise being forced to enter the aircraft next to where external power can be plugged in means your more likely not to forget to disconnect it if you had to use it.

I dare say those two observations may not be part of the reasoning but I see them as a benefit even tho I also find it a pain jumping across the seats.

[NutLoose]

Genghis the EngineerQuote:
Originally Posted by Donalk http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/buttons/viewpost.gif (http://www.pprune.org/private-flying/381220-pa-28-door.html#post5059845)
The PA 28 fuselage is a stressed skin design which means that the aircraft exterior is designed to bear all or some of the loads imposed on it. The more holes you cut into this design (essentially a semi monocoque construction) the more you weaken the load bearing ability of the structure.

As Rainboe has already pointed out it makes more sense to include the only door on the right from an operational perspective. I'm sure it was not structurally motivated.

I've heard both of those arguments before, and frankly I think that they're complete cobblers.

From an engineering perspective, there is no substantial weight or strength penalty in fitting two doors. If there was, the same absurd "design solution" would be in many other aeroplanes or, for that matter, cars.

Also, having flown a lot of hours in PA28s I have never found it an operational advantage - especially when I'd really get passengers strapped in, do a last walk around the aircraft to confirm that everything is secure, chocks out and the like, then finally strap myself in and start up - in short what I do in every other type that I fly. Fast running changes are a rare, and usually foolhardy, thing to do in a small aeroplane: my passengers need a safety briefing, and I want to check they've not dropped anything just outside the aeroplane - all of this is best done with the engine off and usually with me outside the aeroplane at some point.

My best guess is that it was a cost saving measure in the 1960s, and since everybody got used to it, Piper have never gone to the cost and effort of changing the design.

G

Would say cost too

Extra strengthened flap, extra step, extra strengthened wing walkway, extra door, extra handle on external fuselage, then you would have to beef up the flap system to take the weight of a person on either flap at once and if you want to allow pax to use the left door the extra folding mechanism in the P1 for the seat back all equal extra cost.

[hatzflyer]

So all cessnas, luscombes, lots of beech's, tomahawks etc etc are structuraly weak ?
CRAP!

[effortless]

I always thought that it was the same rationale as not giving parachutes to WW1 pilots. ;)

[bjornhall]

Added weight would be the actual penalty of adding another door, in addition to cost. The structure must be beefed up to offset the reduction in strength from cutting a hole in the stressed skin, adding weight.

Only of academical or historical interest these days, since aircraft certified in the last 20 years are not allowed to have only one exit (unless they are single seat or have canopies)... So Piper could not have done what Cessna did and recertified their aircraft under current regulations when production restarted in the 90's. But that might be for the TRRBAPSOI thread...

[Genghis the Engineer]

aircraft certified in the last 20 years are not allowed to have only one exit (unless they are single seat or have canopies)...

Just thought I'd look up the exact words on that:

CS 23.807 Emergency exits
(a) Number and location. Emergency exits
must be located to allow escape without crowding
in any probable crash attitude. The aeroplane must
have at least the following emergency exits:
(1) For all aeroplanes with a seating
capacity of two or more, excluding aeroplanes
with canopies, at least one emergency exit on
the opposite side of the cabin from the main
door specified in CS 23.783.

Do you happen to know the date / issue state that came into play?

G

[mjc123]

Have no particular knowlege on this, but the way I had always rationalised this (if you are going to only have one door) is that you would want to make sure all passengers had exited the aircraft safely first before leaving as the pilot and abandoning the controls - but I can see that working both ways as to my mind would also make sense to have the pilot exit first and to make sure passengers moved away from the aircraft in the right direction...
One flight instructor I flew with also told me cautionary tales of door popping open shortly after take off, scared passenger grabbing pilots arm, leading to stall - never happens with 1 POB he said. Plane is not going to stop flying with an open door. But the PA28 design is hardly going to be changed now!

[bjornhall]

Do you happen to know the date / issue state that came into play?

Was curious myself, so looked it up this morning...:8 It's in Amdt. 23-36, Eff. 09/14/88. Prior to that, aircraft seating 5 or less (with centreline mounted engines) did not need two exits.

[Donalk]

So all cessnas, luscombes, lots of beech's, tomahawks etc etc are structuraly weak ?
CRAP!

I dont recall anyone stating that the above mentioned aircraft were structurally weak.

The view advanced was that a semi monocoque design relies on a minimum number of openings to preserve structural integrity without reverting to the need for additional frames and stringers.

Moreover, in this respect Genghis is correct, insofar as the addition of an additional door will introduce a cost penalty, both in materials, and a more complex manufacturing tooling process.

[Malcom]

aircraft certified in the last 20 years are not allowed to have only one exit (unless they are single seat or have canopies)...
So my PA-28 is 40+ years old thus I am only required to have one door, which is quite handy as thats how they built it.:D


The PA 28 fuselage is a stressed skin design which means that the aircraft exterior is designed to bear all or some of the loads imposed on it. The more holes you cut into this design (essentially a semi monocoque construction) the more you weaken the load bearing ability of the structure.

You suggest more holes make a weaker plane, but it does explain why the Cherokee Six came into being - its so you can have extra doors and windows in a PA-28!:ok:

[tmmorris]

Aircraft certified, not built, in the last 20 years. So they can continue to build PA28 Archer IIIs with one door, because the design is so old, but new designs must have two.

Tim

[hatzflyer]

Never mind the Cherokee six, What about the Breazy!!!!:ok:

[J.A.F.O.]

hatz

I looked up the Breezy - certainly does what it says on the tin.

Looks as mad as a bucket of frogs, still wouldn't mind a go in one, though.

I've never felt entirely comfortable with the Cherokee single door thing, I've got a handful of hours on them, finished my PPL in one back when it would have been legal to certify it, but always really wanted another door - and a better view for that matter.

I think the simple answer is that they got away with the cheapest design they could at the time.

[ExSp33db1rd]

I think the simple answer is that they got away with the cheapest design they could at the time.

Probably right, the British built aerolanes that were an engineering marvel and a pleasure for pilots to fly i.e. Comet, Britannia, VC-10, Concorde, but were not necessarily the best financial successes, whilst the Americans built things that would make money for their Owners.

As a Boeing 707 pilot I was unhappy when a Comet Captain converted to ''my" wonderful 707 and described it as a bag of rubbish. How dare he criticise the most magnificent aeroplane I had ever flown ! "No, he said, a Public Transport aeroplane should be capable of being flown safely by the Company's worst pilot on a day when he feels poorly - the Comet can, the 707 can't, turn your back on it and it will bite you " Some did.

Some PanAm ( Ahhhhh! ) pilots would congratulate us because the British Air Registration Board -as it was then - insisted that the UK reg'd 707's had to have an extra hydraulic pump fitted as a rudder boost, and an increased fin area by fitting a dorsal fin under the fuselage - the PanAm guys reckoned that PanAm take-offs were a cheap-thrill Lottery on the early models until reaching a few knots above V.1, 'cos an engine failure at V.1. left them with insufficient rudder authority to keep straight on the runway, and after V.1 they had insufficent length to safely stop.

I know, you're going to tell me about the early Comet disasters, but then the Americans did learn, and benefit, who knows what might have happened if the British hadn't discovered metal fatigue in aircraft structures when they did ?

One CEO of a U.S.Airline after the Second World war initially refused to fit auto-pilots, " You guys are paid to fly, so fly " Ultimately it was proved that auto-pilots were a safety factor - but also, by maintaining a more accurate track, and altitude, less fuel was burned. Saved money, so auto-pilots were fitted !

Never let Bean Counters near aeroplanes.