Alcohol and flying
 

I was recently speaking to a guy who told me that as a PPL, he does not touch alcohol withing 3 days of flying. While I to an extent, commend this approach, I do find it a little over cautious, especially since I mostly fly at weekends, which is also the only time I drink.

Personally, my rule is that I do not drink within 24hrs of flying and when cicumstances have conspired to mean I have consumed within that period, I have pulled out of flying.

What rules do others have?

I usually don't drink the night before flying. But I might drink a small amount if I'm not flying until the next afternoon and not taking any passengers.

I have no scientific basis for this.

Solution for weekends is clearly to fly on Saturday and then drink Saturday night.

[I think I'd better not tell you about the time, many years ago now, when, whilst training for the PPL, I had a phone call one afternoon. "Hi Tim, it's a nice day, I feel like going flying (this guy mostly had a desk job), would you like an extra lesson this afteroon?" "Sorry, I can't, I had a glass of wine at lunchtime." "Oh look, tell you what, I didn't hear that. Anyway, I'll be in the plane too, so you'll be quite safe. See you in ten minutes?"]

A couple of years ago I was at a fly in barbeque where there were several helicopters. I (who was staying at the place) got chatting to a very pleasant guy and his wife who sank a bottle of wine between them. They said goodbye and walked outside, then to my amazement got into an R22 and literally set off into the sunset.

Rather him than me!

They probably needed the drink to get the courage to get going in the 22!

:D

Some useful information here:

Alcohol & Flying: The new law

LHR breath-test

I've posted this before, which is the result of some research I did in the RAeS library a couple of years ago, but it's still useful....

G



The basic unit of alcohol within the body is mg/100ml of blood (referred to as %mg BAL). Obviously the relationship between how much you drink and BAL is dependent upon sex, weight, and a few other things. But the references seem to pretty much agree on the following rules of thumb for a standard adult:-

1 pint beer: 24%mg within an hour (can be up to 35%mg, depending upon strength of beer which clearly varies)
1 measure spirits: 12%mg within an hour
1 small glass wine: 15%mg within an hour.

The body (liver) then evacuates alcohol at a pretty constant rate of 15%mg per hour - although the references do admit that depending upon physiology it can actually be anywhere between 8 and 25 %mg/hour.


That stuff most of us had some idea about, but certainly it helps work out where we are after a good night out.


Now to the interesting bit - what the various studies gave as effects of alcohol. The various reports, papers and medical textbooks were pretty consistent. From them I came up with the following:-

11%mg - Reduced ability to maintain correct airspeed or flightpath under high workload

15%mg - 1/3 of pilots in fatal accidents had this level or above in their bodies (from autopsy reports)

20%mg - UK legal flying limit. Significant increase in errors on RT, planning and correct following of procedures.

40%mg - US legal flying limit. Major effect on number of errors on RT and following procedures.
- Reduction in g tolerance by between 0.1 and 0.4g.


50%mg - Impaired ability to visually fix or track objects

60%mg - Consistent degredation of long term performance even on low workload tasks.

80%mg - UK legal driving limit

150%mg - loss of self control (exactly what is meant by this wasn't defined)

200%mg - double vision, some loss of memory

400%mg - Loss of consciousness.


Three other notes were interesting...

(1) from a study where they tanked pilots up to 150%mg which was that afterwards when BAL had gone down to zero, visual impairment and disorientation could occur up to 7 hours afterwards.

(2) All the studies agreed that under high workload alcohol degraded pilots' performance much more than under low workload.

(3) Up until very high alcohol levels, virtually all the degredation was of judgment or ability to follow procedure, rather than of actual physical skills.

When I was learning to fly, I made the mistake of going flying one saturday morning with a hangover. Unfortunately, the instructor had decided that the time was right for spiral dives. It put me right off flying for weeks (well days but still dislike doing spirals to this day).

My rule is 24hrs before flying, no alcohol.

(says he who flew yesterday and is now on way to pub :ok: )

8 hours bottle-to-throttle used to be the rule. Increased to 24 hours or more for heavy drinking.

Since the recent regulations stipulating a maximum blood-alcohol level came into force, I believe the CAA have published an AIC detailing the new rules, but re-emphasising the same 8 hours absolute minimum which always used to be the guide-line. However, no one will guarantee that following these guide-lines keeps your blood-alcohol at a legal level.

FFF
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My personal is 12 hours, but that is limited to a few "stubbies" - max 4.

stubbie = 330mil 4.5% alcohol night before, If i'm flying at 9:00am then I stop drinking (after a max 4 beers) at 9:00pm.

Never drink wine or spirits the night before, if i'm doing aeros or have a test/chekout then i don't touch it.

For normal flying , I have a few on friday night (as said max 4), but thats it.

If I was RPT then 24 is about right, no sense screwing with other peoples lives....

cheers <clink clink hic>

7gcbc

The standard text book answer is that 1 unit of alcohol takes, on average, 1 hour, to metabolise.

(Hence 6 pints of Boddingtons is not cleared from your system for about 12 hours.)

However, pilots are a bit of a special case, as there is some evidence which suggests that alcohol can stay in the fluid filled tubes which are responsible for balance, for about 3-4 days.

I guess its horses for courses.

Looking at Genghis's scale, I'm just wondering where the Beer Goggles kick in?;)

I don't set an absolute limit, apart from the 8 hour rule. I know when I'm impaired either through hangover or alchohol, and consequently don't fly. Normally a session means no flying the next day, but a few beers or even a couple of glasses of wine the night before is ok.....

englishal

"I know when I'm impaired either through hangover or alchohol ....."

You may be right, but a couple of notes of caution -

(1) Although the new law makes it an offence to perform an aviation function, or carry out an activity ancillary to an aviation function, when your ability to perform the function is impaired because of drink or drugs (re-wording the existing offence under the ANO), there is now a separate offence of performing an aviation function etc when the proportion of alcohol in your breath, blood or urine exceeds the prescribed limit - regardless of whether your ability is actually impaired. (The prescribed limit for pilots is a quarter of the UK driving limit.)

(2) The Captain arrested and removed from his aircraft at LHR thought he'd know if he was impaired or over the prescribed limit, and was confident he was neither. There was no evidence he was impaired, but he was found to be over the prescribed limit and is now serving a six month prison sentence.


Tudor Owen

Good point....

What I meant was that if I've been on the piss the night before I don't fly, but a couple of glasses of wine, more than 8 hours before flying is ok.....Besides I tend not to do early flying :D Especially if spending the night in Vegas or somewhere ;)

Maybe it is a good idea to ensure that during PPL training all students are taken flying with a hangover for some aerobatic training, or intensive circuit flying. To see your own degredation in performance in a high workload environment, and how nauseous you feel would be enough to put off most from taking risks with alcohol more than any law...

Or just do it in a simple sim - PC based thing would be enough.

G

Only if you can give the sim that certain 'odour'; the mix of oil and vomit...a Chipmunk inverted followed by a few circuits should do the trick.

Having flown (as a pax) in a PA28-236 Dakota at FL90 across the Irish Sea with a monster hangover, I can confirm that the biggest problem I had was the altitude. As soon as we decended to land, I felt a whole lot better!

TPK:ok:

No drinking within 50 feet and no smoking within 8 hours! Read it on a fuel bowser once, lived by it ever since.

Perhaps I should get my eyes checked?

:sad:


T

Never drink and fly. Might spill some. :uhoh:

Years ago when I was learning to fly in Kenya, i partook of a bottle of Tusker lager prior to a solo exercise in a Cessna 150 out of Wilson airport. Hot day at high altitude (5,500 ft) so the density altitude was up around 8,500 feet. Checks complete, off I went and 2 minutes later I wished I hadn't. Suffice it to say that I was only marginally in control of the aeroplane so I now subscribe to the "8 hours from bottle to throttle rule" or is that "Don't drink within 8 feet of the a/c"?
Whatever, a chum and I were viewed as wimps on departure from Morlaix when the Customs chap insisted on a "coupe avant le depart". We were well out over the Channel before the u/c came up...wonder why?