2 min read
Foggy runway

How low is too low?

One of the double-edged swords for pilots is the issue of Part 91 weather minimums. Unlike commercial operators, private pilots can start an instrument approach even when the weather is below minimums. For takeoff, there really aren’t any minimums at all, so a zero-zero takeoff would be perfectly legal. But is that a good idea?

Some instrument pilots do it all the time. Especially for those based at an airport by a river or in a low-lying area, very low visibility takeoffs can be common for morning flights. These pilots argue that such takeoffs are safe because there are often numerous departure alternates – out of 100 ft. AGL, conditions are clear and the are multiple options for an emergency landing that are out of the foggy areas. With a good pre-takeoff briefing and good alternates, a proficient instrument pilot can complete this procedure with no unnecessary risk. Knowing when to use such a trick is part of being a good pilot.

Other pilots would disagree. If it’s too low for the airlines to launch with two pilots and jet engines, why would a single pilot in a Cessna think it’s safe for him? Besides the potential for a mechanical failure shortly after takeoff, there is a very real possibility of hitting deer or birds on the takeoff roll–it’s impossible to see them. And if a pilot bends some metal, the FAA might very well bring up the well-known FAR 91.13 about “careless and reckless” operations. These pilots argue for obeying the IFR takeoff minimums and departure procedures, even if they don’t technically apply to non-commercial operations.

Part 91 operators have tremendous flexibility, but with that flexibility comes a requirement to be use it judiciously. What do you think? Are zero-zero takeoffs safe? If not literally zero-zero, how about takeoffs when weather conditions are below the instrument approach minimums? Add a comment below.

Air Facts Staff
31 replies
  1. David Reinhart
    David Reinhart says:

    Nope, won’t do it. Never have, never will. That’s not to say I won’t take off when it’s below minimums for my departure airport. The drill for my home ‘drome (KFIT) is to have plates for an ILS at Hanscom (KBED)out and briefed if the weather is below minimums for the LPV approach. It would actually be faster to declare and get the vectors to KBED than back around for the home airport. Also, the best LPV approach is often unavailable because of a hot restricted area near FIT.

  2. Tom Yarsley
    Tom Yarsley says:

    The whole idea of a takeoff alternate is to mitigate the risk of being unable to return to the takeoff airport. If you accept that idea, then how far below landing minimums your takeoff airport is, doesn’t really matter – as long as you can get airborne safely. There’s actually a lot to be said for “zero-zero” technique – even when conditions are well above minimums. For one thing, there’s no tentative transition from visual to non-visual cues, which is even more important in darkness. Of course, this whole thing seems less dicey when you’re facing a 400-foot takeoff ground-roll and a 60 kt rotation speed, than it does when those numbers are 5,000 feet and 125 kts…

    • David Reinhart
      David Reinhart says:

      Not so. What really counts is how long it takes to get back on the ground. The minimums for the GPs approaches at my at my airport are almost VFR, so if it’s below minimums, the quickest, easiest way to get back on the ground is an approach at another airport.

  3. Jerry Fraser
    Jerry Fraser says:

    My instructor insisted on practicing zero-zero takeoffs when I was working on my instrument rating. He wasn’t advocating the maneuver so much as letting me know what I was in for if I got any bright ideas. We would line up on the the runway and I would set the DG, don the foggles, slink down in the seat and roll.

    By comparison with what I think of as zero-zero, the foggy runway in the photo above looks inviting. Arguably, once you’re in the air it’s just another cloud (plus, you’re less likely to try any ill-advised turn-backs if the engine quits!), but rolling down the runway using the DG was probably the flight training maneuver I was least comfortable with. “Small corrections” in the air are one thing, on the runway, something else!

  4. David Megginson
    David Megginson says:

    At Canadian airports, the regs require 1/2 SM even for private GA. For light piston singles that break ground at 30–50 kias, I think it would be reasonable to reduce that to 1/4 sm when there are no obstructions, since that’s still more than your entire takeoff roll.

  5. Dick Collins
    Dick Collins says:

    I liked to call them low-visibility takeoffs and I never hesitated to do this. I agree with Tom that it is a good practice to follow on any IFR takeoff — transition to instruments at liftoff — but that does mean no literal zero-zero where you couldn’t see the centerline marking of the runway, Nobody should do this unless comfortable with it and after every increase in risk is evaluated and accepted. The risk in the ground part is no more than that found in a car while driving in fog. We do a lot of things in airplanes that result in variations in risk and it is up to us know what those things are. Otherwise, just fly on clear and calm days when the avoidable risk is at the lowest possible level.

  6. Stephen Phoenix
    Stephen Phoenix says:

    There is nothing overwhelmingly hazardous about low viz takeoffs. Typically, with fog, the tops are not very high and the air is smooth, so it’s really quite pleasant flying. Lightplanes have an advantage over the heavy iron in that the speed required down the runway, before takeoff, is much lower.

  7. Duane
    Duane says:

    If the pilot is perfectly capable of flying the airplane on the gages, then a takeoff in zero-zero is as safe as any other from a pure airmanship perspective.

    But that’s not the only consideration involved with assessing safety and risk.

    An engine failure on takeoff, which seems to be the most likely time to suffer a mechanical failure in piston aircraft, in zero-zero is much more likely to result in a fatality than in VFR or legal IFR minimums or better. If you can’t see anything out the windows, then you can’t very well search for and visually identify the best landing area ahead, avoid obstacles, and/or know when to flare on landing. Nor can you very well return to land at the departure airport should the engine failure occur sufficiently later and higher in the climbout such that the pilot can turn back to land on the the departure airport runway(s).

    These are obvious added risk factors – not with respect to causing an accident, but with repect to surviving the accident. In a single engine piston aircraft, you better be very confident of your engine, or you’re just depending upon sheer luck when taking off in zero-zero.

    • Duane
      Duane says:

      I would add another risk factor for an engine failure on takeoff in zero-zero, or even during any takeoff climb in IMC: most of the time in such loss-of-power accidents that result in fatalities, it’s because the pilot did the proverbial stall-spin into the ground.

      That result is usually due to the pilot, who in the heat of the moment when he/she has only a couple of seconds to react propertly, fails to make the necessary “big push” on the stick. When the aircraft is already nose-up with takeoff/climb trim dialed in at relatively low airspeed, with significant rudder applied to counter p-factor, a stall-spin is but seconds away. The pilot who takes off in zero-zero or even low IFR conditions ought to have plenty of recent practice in departure stall recoveries under the hood if the split-second instinctual reactions are going to kick in soon enough to avoid a loss-of-control catastrophe.

  8. Michael Teninty
    Michael Teninty says:

    Have you ever seen another airplane, or an airport vehicle, or an animal enter the runway during zero-zero conditions? I haven’t (because visibility is zero)… And that is why I will never takeoff or land zero-zero.

  9. Tom Yarsley
    Tom Yarsley says:

    Have you ever seen another airplane, or an airport vehicle, or an animal enter the runway during CAVU conditions? The ensuing collisions are just as… impactful… as they would be in zero-zero weather.

  10. Daniel Villeneuve
    Daniel Villeneuve says:

    I agree entirely with this position. I recently practiced simulate engine failures on initial climb in my Turbo-Arrow, climbing at Vy of 97 KIAS with, of course, a nose up attitude, when power is reduced to zero airspeed drops to 80-85 knots in mere seconds and it takes a lot of pushing and trimming to get to best glide speed. And that is in an “anticipated” failure in VMC…it would be very dicey in full IMC seconds after a low-vis take-off.

  11. Greg
    Greg says:

    Can not consider there is a topic that’s eclipsed daily Kardashian brunch reports. “Ermagerd, Ebola, we are all gonna daaa!” The quantity of narrow minded people on earth is amazing.

    MORT MASON says:

    Over the years, I’ve made a handful of truly zero-zero takeoffs, including several while operating a seaplane. I don’t consider them especially dangerous, considering the number of engine failures nominally encountered in thousands of takeoffs over the years. The latest was from the LaFayette Hotel at Marietta, Ohio, and from the surface of the Ohio River there. By DG course, I taxied upstream until it became truly dark, which told me I was passing beneath the bridge there. After a very slow 180-degree turn, a tight compass course downstream was easy to maintain, and the amphibious C-206, as usual, just flew itself off.

    Are zero-zero takeoffs for everyone? I believe not. But if you fly five days a week, and can TRULY control your airplane, it has never seemed especially chancy to me.

  13. Don Woodbridge
    Don Woodbridge says:

    The subject of 0:0 departures will always be controversial as long as it is legal. During instrument training we practiced it, although my CFII pointed out the pitfalls–low altitude engine failure being perhaps the most dangerous, but certainly not the only danger.

    Can a 0:0 departure be accomplished safely? Of course. But the margin of safety is certainly reduced. Most “0:0” departures actually have a “short but not zero” visibility such that you can use the center line to stay lined up with the runway on the takeoff roll. This is not true with practice 0:0 departures, where the foggles limit your view to the instruments.

    Having experienced an engine failure on takeoff in a single engine aircraft, I personally do not discount the possibility that something will happen to force me to return to the takeoff runway. Fortunately for me, when the engine quit, I had just rotated and was climbing out over a 9,000 ft runway at a former SAC base (KAUS 17L). There was still enough runway “ahead of me” to put it down, and brake for the last turnoff. There is something to be said for another mile+ of runway ahead of you when the engine quits!

  14. Warren Webb Jr
    Warren Webb Jr says:

    I have done one ‘low-vis’ takeoff and I thought there was basically no more risk than flying at night. Good proficiency on instruments and in airplane attitude control at liftoff is critical.

    • John Zimmerman
      John Zimmerman says:

      Lots of pilots risk their life every time they take off in good weather – or drive to the airport for that matter. The question is, how much additional risk does this procedure entail?

      Maybe more interestingly, what are everyone’s takeoff minimums? If zero-zero is a bad idea, is a half mile ok? One mile? VFR? Where’s the line?

  15. Jerry Smith
    Jerry Smith says:

    In zero-zero you have no idea what’s out there, & its risking your life & other peoples life, even those that come to rescue you.

  16. Oliver
    Oliver says:

    Issues with very low VIS takeoffs:
    – controllability ie being able to track the RWY centerline.
    – without proper low VIS procedures in force at the airport, there is no guarantee against RWY incursions (planes, vehicles and live animals…). Without LVP, you should be able to reasonably see what lies ahead of you (it would also mean that other live beings have a chance to see and avoid you…). Sounds like common sense.
    – engine failure on a single engine piston aircraft: unforgiving, same as for night flying ie unsafe in my opinion.

  17. Duffee Ricks
    Duffee Ricks says:

    Low Visibility takeoffs require you to be totally proficient at instrument flying. The transition from visual to instrument conditions is nearly instantaneous at rotation. With that said, low vis takeoffs should not be attempted if you are not trained and proficient at them.

    A good set of criteria for minimum visibility is provided by the FAA in the 8900.1 handbook.
    Section 9 Lower Than Standard Takeoff Minima

    Summarized as:

    Adequate visual reference, (1/4 sm Vis or RVR1600) / This might be reduced somewhat for non-high performance planes. ie Rotation speed less than 60KIAS.

    Runways with HIRL and Center Line Lights RVR 500

    With an approved HUD takeoff guidance system, HIRL, and CLL
    RVR 300/300/300(75 m)

    MORT MASON says:

    Hey Duffee,

    We are talking about zero-zero takeoffs here. There is no “transition” from visual to instruments, as you’re on the instruments before the throttle is advanced for the takeoff roll. All you’ll be using at first is the DG or some other more sophisticated instrumentation. Your biggest problem, if single engine, will no doubt be engine torque, which may cause your plane to drift left and away from the centerline, which you very likely cannot see at any rate.

    • Warren Webb Jr
      Warren Webb Jr says:

      It may be called a zero-zero takeoff, but the accompanying picture shows several centerline stripes visible and would approximately represent the conditions which would have to exist for visual guidance before liftoff and I took it to represent the conditions intended for purposes of the article. I found two other explanations of zero-zero takeoffs in an Aviation Safety article – where the aircraft enters IMC before reaching DH or MDA on a related approach, or where the crew can see neither the end of the runway nor a definite ceiling, and must transition to instruments when the wheels leave the runway. So that would mean that on the runway there are visual references and guidance. Zero-zero is a catchy name but I doubt it ever applied literally.

  19. David Megginson
    David Megginson says:

    It seems to come down to the definition of “zero”. Do we mean actual “zero” (e.g. I can’t see the tip of my nose), or just less than 1/8 SM, the minimum visibility usually reported?

    I grew up near the east end of Lake Ontario and experienced my share of thick fogs, but I’ve never been in one where I couldn’t see at least 20-30 ft ahead of me in daylight.

  20. Dave Sandidge
    Dave Sandidge says:

    I’ve done a couple of ‘for-real’ zero-zero takeoffs, and I don’t really care to do any more of ’em. Flying freight, you’re sometimes pushed into things that you’d rather not do if you want to keep your job. I hope things have changed since I did my time in that racket years ago…. Anyway, we always knew we were rolling the dice when we attempted such shenanigans. We learned a lot of things about flying, but we lost a bunch of guys in the process. In part ’23’ twin-engine airplanes if we had lost an engine shortly after V1 or after liftoff with anything more than a very light load on board we wouldn’t have had any chance of survival at all – or very little.

  21. Tobias
    Tobias says:

    If Commercial aircrafts aren’t allowed, I would not do it.

    Commercial Aircraft have multi engines, better equipment (de-ice etc.)
    I fly a single engine.

    If one engine fails – good luck with the emergency landing.

    And even with multi engine… commercial operators tend to have much more power – so forget about it in a small plane.

  22. Mike Lee
    Mike Lee says:

    A o/o takeoff is probably something that a pilot should do once just to find out what a dumb idea it really is. The conditions have to be right I.e. Flat land, long, wide runway, two or more engines, lots of recent experience in that airplane. I did mine years ago. The vis was so low that I could not see two stripes at the same time. My biggest concern was a clear runway. ( the owner of a small local airport had once gotten angry with pilots and parked a bulldozer in the middle of the runway). The airport was fenced and I told everyone that I could what I was going to do. I also taxied the length of the runway. While I was roaring down the runway straining to see the next stripe I had vision of seeing a bulldozer. There was a second or two of concern when I rotated and I could no longer see the stripes and was not quite airborne as the runway was quite narrow. That one was quite enough. I decided that I would never do another unless the natives were shooting at me.

  23. John
    John says:

    I have done it numerous times out of Watsonville, CA where early morning marine layer is common (I commuted by air to Palo Alto). It is legal yet not risk free. If something goes wrong (engine stop, blown tire, etc.) the lack of forward visibility can bite you. Best to wait for visibility to improve.

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