# What do civilian jet pilots do in their last on-tarmac plane check? **URL:** \ **Category:** Factual Questions\ **Created:** [September 25, 2011, 5:22am UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533 "2011-09-25T05:22:52Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [September 25, 2011, 5:22am UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/1 "2011-09-25T05:22:52Z")
I have read [no cite] or seen [ditto] or been suckered by airline commercials that it is a rule/law that the pilot of a commercial jet do a once-over of his jet on the ground. Is this true, and if so, what could he possibly learn? ---
**Author:** ![Oakminster](https://avatars.discourse-cdn.com/v4/letter/o/77aa72/32.png) [@Oakminster](https://boards.straightdope.com/u/Oakminster)\ **Post date:** [September 25, 2011, 5:30am UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/2 "2011-09-25T05:30:30Z")
If it is anything like the walk around done in the military, he’s looking for anything unusual. All engines where they should be, no obviously missing parts, no cracks, no [bullet holes](http://abcnews.go.com/US/bullet-hole-found-us-airways-plane/story?id=13247926)…(warning, link has auto-playing video with sound, as well as text) ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [September 25, 2011, 5:32am UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/3 "2011-09-25T05:32:16Z")
Preflight inspection. [FAR 91.7](http://www.risingup.com/fars/view_far.php?part=91&type=FAR&num=7) > [@](#): > > (b) The pilot in command of a civil aircraft is responsible for determining whether that aircraft is in condition for safe flight. Whether the pilot does it on commercial airlines, I don’t know. I suspect the co-pilot does it. ---
**Author:** ![Digital\_is\_the\_new\_Analog](https://avatars.discourse-cdn.com/v4/letter/d/a88e4f/32.png) [@Digital\_is\_the\_new\_Analog](https://boards.straightdope.com/u/Digital_is_the_new_Analog)\ **Post date:** [September 25, 2011, 3:00pm UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/4 "2011-09-25T15:00:05Z")
IANAP. I took a ride with a friend who is a private pilot about 15 years ago out in California. I joined him for the inspection. The thing I remember from it is him drawing some fuel from a port in the bottom of the tank. He told me it served two purposes: 1. If there was any water in the tank, it should settle to the bottom. The port was at the low point of the tank. If the fluid doesn’t look like fuel, then you don’t fly. 2. There is a particular odor you can detect if the fuel is somehow bad. I’m not familiar with this, but took it at face value. I should point out that, since this was 15 years ago, he felt no need to have a third item in his list. -D/a ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [September 25, 2011, 3:14pm UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/5 "2011-09-25T15:14:25Z")
> [@Digital\_is\_the\_new\_Analog](#): > > I should point out that, since this was 15 years ago, he felt no need to have a third item in his list. 1. Gasoline is lighter than water, so it will float to the top of the tester. Water doesn’t burn well, so you don’t want it in the system. 2) AVGAS smells like gasoline. Jet fuel smells like kerosene. You don’t want to put jet fuel in a piston engine. Piston engines need higher-test fuel. Also, fuels are colour-coded. If you mix them, they become clear. Most piston-engine planes today run on 100 octane low-lead (100LL). You wouldn’t want to put 80 octane into a plane that requires 100 octane. 3) A third thing to look for is sediment. It will sink to the bottom. If you see sediment, have it checked out. Here is a typical checklist for GA aircraft. Commercial jets have more systems but this will give you the idea of what’s being looked at: [Cessna 172](http://www.coryat.com/c172/PAGE1.htm) ---
**Author:** ![Nametag](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nametag/32/406_2.png) [@Nametag](https://boards.straightdope.com/u/Nametag)\ **Post date:** [September 25, 2011, 3:36pm UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/6 "2011-09-25T15:36:34Z")
[This](http://freechecklists.net/getDoc.asp?fpath=doc/747checklist.pdf) purports to be the recommended checklist for a Boeing 747-400. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [September 25, 2011, 4:35pm UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/7 "2011-09-25T16:35:22Z")
Thanks for these two cites, which are pretty cool. But what I was wondering what the big jet commercial pilots are checkin on the ground, not in the cockpit. I know there’s a doper who is one of those pilots… ---
**Author:** ![mnemosyne](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mnemosyne](https://boards.straightdope.com/u/mnemosyne)\ **Post date:** [September 25, 2011, 4:47pm UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/8 "2011-09-25T16:47:48Z")
IANAP, but the final walk around is to make sure that access ports are closed, that there is no observable damage to the aircraft, that all [pitot](http://sportys.com/source/images/products/large/9650.jpg)and [engine](http://www.kinnearupholstery.com/pics/challenger_300_honeywell_as_907.jpg)covers, [landing gear pins](http://www.aeropin.com/images/kit1c.jpg) and other safety tags have been removed, to observe the level of snow/precipitation/icing accumulation on the control surfaces, that all lights are functional, that there are no fuel or hydraulic fluid leaks or other curiosities with regards to the appearance or configuration of the aircraft. Since the pilot has final authority over the plane, he or she can choose to delay a flight until an unusual situation is repaired. It’s a little like when you did driver’s ed; you were probably told to examine the condition of your tires and occasionally verify the car’s lights and see if anything looks wrong before driving. Most people don’t do this on a regular basis, then get surprised when a flat tire slows them up 2 blocks later! 🙂 ---
**Author:** ![obbn](https://avatars.discourse-cdn.com/v4/letter/o/d6d6ee/32.png) [@obbn](https://boards.straightdope.com/u/obbn)\ **Post date:** [September 25, 2011, 5:15pm UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/9 "2011-09-25T17:15:39Z")
I used to fly (got my ticket pulled when I hurt my back. For some reason the FFA doesn’t let you fly when you use morphine) and I would always do a post flight walk around the aircraft. I would do this to check for any damage, loose parts, etc. that might have occured during flight. If I found anything out of place I would then write it up and notify my mechanic. Of course the same procedure was done prior to flight. The time to locate a potential problem is on the ground, not in the air for then your options are pretty limited. ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [September 25, 2011, 10:50pm UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/10 "2011-09-25T22:50:47Z")
The question is about commercial jet pilots. I don’t fly a lot but I don’t think I’ve ever seen a member of the flightdeck crew on the ground at a commercial airport. The only preflight check they seem to complete is the game score and Starbucks menu. Sure, ther’s a lot of other folks scurring around down there but I’ve never seen a ‘suit’. Does the pilot and/or copilot really walk around the plane? ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [September 25, 2011, 10:53pm UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/11 "2011-09-25T22:53:56Z")
I’ve seen pilots/co-pilots looking over commercial aircraft. ---
**Author:** ![BrotherCadfael](https://avatars.discourse-cdn.com/v4/letter/b/977dab/32.png) [@BrotherCadfael](https://boards.straightdope.com/u/BrotherCadfael)\ **Post date:** [September 25, 2011, 11:04pm UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/12 "2011-09-25T23:04:56Z")
> [@obbn](#): > > for some reason the ffa doesn’t let you fly when you use morphine) bastards!!! ---
**Author:** ![StrangerThanFiction](https://avatars.discourse-cdn.com/v4/letter/s/f05b48/32.png) [@StrangerThanFiction](https://boards.straightdope.com/u/StrangerThanFiction)\ **Post date:** [September 26, 2011, 12:27am UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/13 "2011-09-26T00:27:32Z")
…but the FAA doesn’t seem to mind. Anyways, the pilot in command (captain) is responsible for making sure the airplane is airworthy prior to flight. In the airline world, the captain relies heavily on the airline’s maintenance personnel to make sure the airplane is safe and legal to fly, and to make the crew aware of its maintenance status. That said, many captains feel it’s their responsibility to give the airplane a good visual once-over before it goes flying. The captain has the authority to delegate this task to other crewmembers if he wishes, and by that I mean he makes the first officer do it when the weather is crappy 😃 ---
**Author:** ![ElvisL1ves](https://avatars.discourse-cdn.com/v4/letter/e/5daacb/32.png) [@ElvisL1ves](https://boards.straightdope.com/u/ElvisL1ves)\ **Post date:** [September 26, 2011, 12:36am UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/14 "2011-09-26T00:36:04Z")
> [@Johnny\_L.A](#): > > You wouldn’t want to put 80 octane into a plane that requires 100 octane. I don’t think 80-octane is even produced anymore. I’ve only seen 100LL and ethanol-free mogas at airports. And only Jet-A as a turbine fuel. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [September 26, 2011, 12:55am UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/15 "2011-09-26T00:55:51Z")
> [@ElvisL1ves](#): > > I don’t think 80-octane is even produced anymore. I’ve only seen 100LL and ethanol-free mogas at airports. And only Jet-A as a turbine fuel. You may be right about 80 octane. A quick google search seems to confirm it. Yes, Jet-A is only for turbines; which is why it can’t be used in piston engines, which require something with higher ‘octane’. (I don’t think kerosene is measured in octane, but it’s certainly less volatile than avgas.) But there still seem to be too many mis-fuelings. ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [September 26, 2011, 2:00am UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/16 "2011-09-26T02:00:58Z")
> [@Nametag](#): > > [This](http://freechecklists.net/getDoc.asp?fpath=doc/747checklist.pdf) purports to be the recommended checklist for a Boeing 747-400. Linky no worky. ---
**Author:** ![Deereman](https://avatars.discourse-cdn.com/v4/letter/d/a3d4f5/32.png) [@Deereman](https://boards.straightdope.com/u/Deereman)\ **Post date:** [September 26, 2011, 5:58am UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/17 "2011-09-26T05:58:01Z")
> [@Johnny\_L.A](#): > > You may be right about 80 octane. A quick google search seems to confirm it. > > Yes, Jet-A is only for turbines; which is why it can’t be used in piston engines, which require something with higher ‘octane’. (I don’t think kerosene is measured in octane, but it’s certainly less volatile than avgas.) But there still seem to be too many mis-fuelings. Diesel volatility is measured in Cetane, though I don’t know about Kerosene. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [September 26, 2011, 6:22am UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/18 "2011-09-26T06:22:06Z")
> [@Johnny\_L.A](#): > > Yes, Jet-A is only for turbines; which is why it can’t be used in piston engines, which require something with higher ‘octane’. You could use it in a [Diesel aircraft](http://en.wikipedia.org/wiki/Aircraft_diesel_engine); they aren’t common, but they do exist. ---
**Author:** ![StrangerThanFiction](https://avatars.discourse-cdn.com/v4/letter/s/f05b48/32.png) [@StrangerThanFiction](https://boards.straightdope.com/u/StrangerThanFiction)\ **Post date:** [September 26, 2011, 1:02pm UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/19 "2011-09-26T13:02:17Z")
> [@Dr.Strangelove](#): > > You could use it in a [Diesel aircraft](http://en.wikipedia.org/wiki/Aircraft_diesel_engine); they aren’t common, but they do exist. I teach part time at a flight school that has two such aircraft, and we fuel them exclusively with Jet-A. Not only is jet fuel easier to find at airports than diesel, but diesel fuel tends to gel at low temperatures. Because of this, if the airplane has been fueled with diesel fuel we must observe minimum fuel temperature restrictions for both engine starts and takeoff. In the middle of winter these fuel temperatures would be very difficult for us to achieve unless the airplane was pulled into a heated hangar between each flight. In our case, opening and then reheating the hangar four or five times a day in the middle of winter is prohibitively expensive. ---
**Author:** ![smithsb](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/smithsb/32/12107_2.png) [@smithsb](https://boards.straightdope.com/u/smithsb)\ **Post date:** [September 26, 2011, 1:52pm UTC](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533/20 "2011-09-26T13:52:58Z")
> [@Johnny\_L.A](#): > > You may be right about 80 octane. A quick google search seems to confirm it. > > Yes, Jet-A is only for turbines; which is why it can’t be used in piston engines, which require something with higher ‘octane’. (I don’t think kerosene is measured in octane, but it’s certainly less volatile than avgas.) But there still seem to be too many mis-fuelings. Just about everything in the US military runs on Jet -A as one possible fuel. Not just the turbines in helicopters and the M1 tank. It was pretty much the only fuel during Desert Storm I. There were problems then with the lubricosity (word??) back then - lots of failed fuel pumps and some gasket problems. Everything diesel ran on it though. [Next page](https://boards.straightdope.com/t/what-do-civilian-jet-pilots-do-in-their-last-on-tarmac-plane-check/597533.md?page=2)