howard40 wrote:The presentation indicates the fuel injection is "timed" I thought the fuel injection just dumped a metered amount of fuel into the intake channel just ahead of the intake valve and when the intake valve opens it "snatches " the air (with fuel in it ) into the cylinder? do i have this right? it is not like a diesel fuel injection on a tractor that has "timed into the cylinder" injection.
HP
You are correct. That has been changed with the new version of the ground school I have been working on. The fuel system has been expanded on a great deal and I discovered that the fuel injectors are not timed. They are the constant flow type. Once the spider (fuel valve) reaches a predetermined pressure it sends it to all of the injectors.
-The only way to know the engine driven hydraulic pumps are working is to cycle the gear handle on the ground. I always start the left engine, cycle the handle (ie move the handle to the down position and wait for the gear handle to pop back to neural) and then start the right engine. On shut down I shut down the left engine and cycle the gear handle again before shutting down the right engine. This way both pumps are independently checked on each flight
-Pilots should pay attention to how long it takes for the handle to return to neutral after the gear is retracted. An excessively long time for the gear to cycle is indicative of gear problems and should be looked at.
-If the gear handle does not cycle to neutral, the system is still pressurized, and the flight should no be continued as you will burn out the hydraulic pumps. If this happens to you it is usually the nose gear micro switch that is the problem. Try a gentle forward bunt, this will sometimes get the gear to bounce up enough to activate the switch and allow the system to finish the retraction cycle, but again get it looked at ASAP.
The two most important parts of the walk around with respect to the gear IMO is to check that the inner main gear doors (Often called the "D" doors, because of their shape) should be tight up against the bottom of the wing and you should not be able to wiggle them. If they are hanging a bit or loose the aircraft is unservicable. The second thing to watch for is the nose gear scissor link pin. That is the pin that joins the upper and lower bars of the scissor. This is often by removed by maintainance to make it easier to maneuver the aircraft in the hanger. If the pin were to fall out many bad things will happen.
The Fuel System
- The fuel guages are useless. Do not believe what they tell you. You have to start from a known quantity and have a very good handle on actual fuel flows (A fuel totallizer IMO should be a mandatory item for this aircraft). The only value they have is they are usually accurate when showing empty so if you are trying to get the last bit of fuel out of the aux's you can (if the system has been calibrated relatively recently) wait until they show empty before switching back to the mains. However monitor the fuel pressure guages as you get a second or two of warning by means of fuel pressure fluctuations before the engine actually dies if you blow the tank.
- you should never run a tank dry (ie run untill the engine stops). It is very hard on the engine and the engine may not restart due to vapour in the lines. If you do inadvertently blow a tank immediately retard the throttle on the effected engine to idle.
- If you can see fuel when looking in the main tank filler cap you have about half tanks. I never takeoff in an aircraft I have not been just flying (ie an aircraft that has done some trips by someone else) without being able to see fuel when I look in the tank cap opening.
Single engine performance
Unfortunately your PPC training will be done in an empty airplane. With only 2 persons and probably half tanks the Navajo does quite well on one engine. However this performance is not indicative of what the aircraft will do at max gross on a hot day. I suggest your power point presentation include a few worked engine failure problems using the POH charts, starting with a typical summer takeoff scenario, max gross 1000 ft ASL 30 deg C, max gross, and including a few more at lighter weights and cooler temperatures. This will show the best possible runway length required for a rejected takeoff and the available single engine rate of climb which can then be converted to a ft per nm climb gradient. Apply this data to a couple of your operations typical airports.....I guarantee it will give pause for thought......
My personal feeling is any single engine climb rate below 100 ft per min means there is no way you can successfully continue after an engine failure right after takeoff. I personally plan on automatically closing the throttles after an engine failure until I have blue line speed, positive rate of climb, the gear and flaps are up, and I am clear of any immediate obstacles. In any case a Navajo ground school should IMO include a serious discussion about the available performance on one engine under various conditions and what are the most appropriate actions for an engine failure at each point in the takeoff sequence.
Here is the latest iteration of the Navajo Ground School. I have been kinda busy flying the HO versus working on this presentation. I will be putting some more time into it soon and posting
Items Not yet included
1. Vortex Generator Kit
2. Upgross Landing gear
3. Calaco vs Duke Flaps (Split Flap detection)
3. Mixture management so as not to crack jugs (basically leave it leaned...i think there is a thread on this already)
4....whatever I think of while studying again.
Just wanted to say your doing a great job with this presentation! I have thoroughly enjoyed reading all the information you have collected. And as a 200hr wonder who is trying/hoping to get a job flying one of these it is good getting some exposure to the machine that I would otherwise not have.
Hey X-15, I didn't look at your power point yet but tip of the hat nevertheless. Here is my random ramblings on the Navajo.
Moving throttles slowly for new guy. Wiggle them incrementally.
So as not to take 4 minutes to set climb power- know where throttles will go approximately so you can pull them to there then fine tune.
Leave your hand on the gear handle 'stopper thingy' when selecting gear down. Pump should take 9 seconds on one engine and 6 on two (I think). Plus you -feel it- when the gear is down and locked.
The door. Hold the handle full open when moving past the 'dogs' on closing and opening. No distractions when working with the door.
Pretakeoff or lineup check should include a confirmation your seat is locked.
Aftertakeoff should have a engine visual check. Careful if your single pilot in crap... or two crew - not good to swing head around. Look at the tail for smoke out of the respective engine.
Spray LPS (the right number, 3?) on the gear micro switches. They freeze.
If your more then four pax - sit the fat guys forward and put all bags in nose. Less then four have them aft. This is a good memory item. Remember this though when the guys are walking to the plane and tell them how you want them to sit.
Climb power should be 35-36 inchs and 2350 RPM. Not because Im an engineer but because its easy to have it slightly off on the high side and that is mean.
Use your GPS's timer for tank changes, also the VNAV function is helpful in the prairies 200 or 300 fpm is nice. In the mountains its very helpful.
Stage cooling can be 1 per minute, I don't do that. 2 per 2 minutes or when your doing a big star or in the mountains with lots of waypoints on the way down. 2 inches for every 6-7 miles.
Don't pickup IAS in the decent. I think thats dumb. Makes things louder and cabin pressure change.
Don't load the electrical system when your -idling- onto the runway.
Lots of voltage regulators crap out. Understand the parallel system and how to check its the voltage regulator and not the alternator. You wont mis diagnose something and you wont be as scared in IMC when one alt doesn't seem to be working.
Leave the heater inlet air vent open. Also, turn the heater 5 minutes to landing. 10 minutes if its snowing so you don't get an ice box if its staying outside.
I don't agree with using circuit breakers as switches. No matter the ambient or engine temperatures. The engine shouldn't flood at all at MICO. If the engine does and/or doesn't shut down nicely when you go MICO you NEED to get work done. They're pretty easy to start and keep running when its a hot start and hot. Not like some Continentals.
No headsets on dash.
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God speed. Hope you and the Navajo are getting along.
One major glaring error that I can see is you haven’t given yourself any credit in the document or any way to contact you. You will want to do this in order for users to let you know of any minor errors they find as not everyone using this GS will know to find you here. Also larger companies may want to use this document and they may want to contact you to gain permission to use it and or perhaps even ask you to teach the GS.
Don’t be shy, it’s a good production, take credit you deserve it.
I’ve only read part-way through two items popped up.
Slide 24 “#4 Friction Lock” is listed but not labeled. A pointy arrow or something would be nice to know the location.
Slide 39. “boot pump” I assume you meant “boost pump.”
The link above is not working..
I used to fly the PA31 both the Navajho & chieftain, so I have been looking for some material on this plane. Can U pls share with me the groundschool that U put together & also if U have a checklist or procedure guide for pilots.
Bit of a thread revival here, but I'm getting into a PA-31-325, and just wanted to convey kudos on the amount of work put into the presentation. There are some differences with the 350, but most info applies.
howard40 wrote:The presentation indicates the fuel injection is "timed" I thought the fuel injection just dumped a metered amount of fuel into the intake channel just ahead of the intake valve and when the intake valve opens it "snatches " the air (with fuel in it ) into the cylinder? do i have this right? it is not like a diesel fuel injection on a tractor that has "timed into the cylinder" injection.
HP
You are correct. The fuel is metered not timed.
That being said. I am no longer flying the navajo. I never had a chance to finish the ground school as much as I would have liked. I would however like to see it get finished and go on to help others. I am looking for a locker where I can post the PPT files. Anyone interested in finishing up the project and posting it here for others?
Bit of a thread resurrect but the 4shared hosting now asks for some registration in order to download the file. In my experience Mediafire doesn't, among others. Also, for hosting the file and adding some sort of version control mechanism, Github could be one way to do it, unless someone knows of an MS Office specific system.
Hi, I have recently been hired to fly right seat in a PA31-350 beginning in May. Would I be able to get a copy of your ground school slides? I'd like to start studying the aircraft.
Thanks
X15, I tried to PM you with no success. Just took a Navajo Chieftain captain position and was going about doing a ground school of sorts for myself in prep for the PPC. Still interested in sharing it? That'd be great.
Thanks
Sorry guys. Stopped monitoring this thread a long while ago. The link above seems to be the latest link. Should work for everyone. I would post the PPT. But its huge with all the pictures.
You should get your training capt to show how to burn all the fuel out of the inboard tanks without losing an engine, or having it cough and sputter (pax don't like that) when fuel gets really low pay attention to fuel pressure. It will fluctuate as it grasps for the last bits, immediately switch to outboards and flip on the boost pumps, it will keep humming without so much as a hiccup.
Fly safe folks.
My first time on the HO was as single pilot Capt after 5 hours of day VMC training at the home drome. It was a little un-nerving to blast off into 300' and 1 mile a few days later because it was VFR.
Always Remember (Skin, Tin, Ticket) in that order!
Sorry to drag up an old thread, but unfortunatey for me and others, that link is dead these days....
Any chance x15 or someone else with a copy of the fantastic ground school (so I've read) would be able to post a link for myself and others that might be switching to the PA31-350 soon?