What are standard departure minimums?

This might be obvious, but I find it difficult to interpret correctly the term "standard", when it refers to the takeoff phase of the flight.

Take, for example, the takeoff minimums for the La Guardia airport, page L16. For Runway 13, it states 400' ceiling height and 2¼ statute (I think) miles visibility but it does not mention any climb gradient. Is it implied that it follows the "standard" climb gradient of 200 feet per nautical mile? Next, it states that alternatively one can takeoff with the "standard" visibility rules, but only with a climb gradient of at least 280 FPNM until it reaches to 500 feet altitude. Which exactly are these standard visibility rules? The only source I remember finding states a requirement for 1 statute mile visibility for 1-2 engines aircrafts and 1/2 statute mile visibility for aircrafts with more than two engines, but no requirement for ceiling height.

Another example can be found by looking at this SID. Its takeoff minimums description states that for runway 4 "Standard" takeoff minimums apply. In addition, for runway 13, it states "400-2 or Standard with minimum climb of 280' per NM to 500." Does this mean that for "400 feet ceiling height - 2 statute miles visibility" the "standard" 200' per NM climb gradient applies, while for "standard" visibility a 280' per NM climb gradient is required?

I would be really grateful if someone could help me clarify the above rules.

Is this a trick question? If you say there aren’t any prescribed takeoff minimums for Part 91 operators, you would be correct; however, just because something is legal doesn’t make it smart. You might even have heard an instructor saying you can take off if it’s “zero-zero.” That advice is as impractical as it is, well, stupid. Flying involves risk. We can’t let ourselves be paralyzed by those risks, but we certainly need to manage them, so here are some factors you might want to consider in making an IFR takeoff decision.

Obstacle Clearance
First and foremost, you need to know if your aircraft performance is adequate to meet the climb requirements for the specific departure you’re about to execute. These minimums are found in the Takeoff Minimums and (Obstacle) Departure Procedures. Not sure what I’m talking about? You aren’t alone. You might be surprised to know how many applicants for an instrument rating don’t know where to find this information or how to apply it.

The climb rates specified in departure procedures are in feet per nautical mile, so you need to convert those figures into feet per minute based on your groundspeed. If the required climb clearances are even close to your aircraft performance, don’t bet your life. Wait until the ceiling and visibility are good enough to avoid the obstacles visually. If no obstacle procedures are posted, you still must be able to climb at 200 feet per nautical mile. This should not be much of a problem for most airplanes at sea level, but it could be questionable as density altitude increases. Light piston twin drivers already know a 200 feet per nm climb rate might not be possible on one engine, so it would be wise to know if there is lower terrain around the airport. To maneuver safely around terrain until you can return for landing or climb to the minimum safe altitude would, of course, require that you have adequate visibility and cloud ceilings. As a minimum visibility, you might want to consider having 1 mile of visibility for every 60 knots you are flying. Sixty knots: 1 mile visibility; 120 knots: 2 miles visibility, etc.

Here’s an example of how you might frame your takeoff decision at El Paso International Airport (KELP), in Texas: The takeoff minimums for Runway 26L at KELP as published in the Takeoff Minimums and (Obstacle) Departure Procedures are standard with minimum climb of 490 feet per nm to 6,300 feet.

An airplane climbing at 90 knots would need to climb at least 735 feet per minute to avoid obstacles. With El Paso’s field elevation being about 4,000 feet, this might be difficult for some airplanes and impossible for a light twin on one engine. In this case you would have two options: Wait until the ceiling and visibility allow you to climb under VFR to 6,300 feet, or take off on Runway 22, which has a standard climb gradient of 200 feet per nautical mile. Given the obstacles present for Runway 26, taking off on Runway 22 would represent less risk under any circumstance, making the slightly longer taxi a small price to pay.

Another issue you might encounter is being assigned a departure procedure you hadn’t planned on. The Instrument Procedures Handbook makes it clear that if you can’t comply with the climb gradient on the SID, you shouldn’t accept the clearance. Sometimes you might receive your clearance while you are taxiing, just before takeoff. Don’t accept a departure procedure unless you’re sure you can meet any required climb gradients and, of course, navigate the departure procedure.

Aircraft Malfunctions
If you want to be conservative enough to plan for the unfortunate event of an engine failure after takeoff, which you should, you want enough visibility and a high enough ceiling to find a place to land and execute a forced landing under Vmc. Circling minimums are a good start. Even with a relatively minor malfunction, flying an instrument procedure can be more difficult than you imagine. Being able to make a visual approach will greatly reduce your workload.

I realize you certainly can’t plan each phase of flight based on the ability to safely recover from every possible malfunction, but you can minimize the risks with a little planning. To that end, you might want to consider a “takeoff alternate,” an airport with better weather near your departure point that you can safely reach in the event of an aircraft malfunction. Simply preparing mentally for this event can significantly improve your prospects for a favorable outcome.

Transition to Instruments
It takes all of us some time to transition from visual to instrument references. That time is largely a function of experience and proficiency; some pilots take a second or two, and some take longer. I’ve seen many pilots level off, or even descend, while they transition from visual flight references to flight instruments. This is understandable; after all, how many times have most pilots, particularly newly instrument-rated pilots, actually done this? Sure, I know it’s part of the Practical Test Standards for an Instrument Rating, but doing this at low altitude in the weather is a bit different from simply putting on a pair of foggles.

Reasonable IFR Takeoff Minimums?
For commercial operators, the FAA requires a minimum of 1 mile of visibility for single- or twin-engine airplanes, and chances are fairly good these crews are both experienced and proficient at what they are doing. My suggestion for newly minted instrument pilots is to delay departure until the ceiling and visibility are at least at or above circling minimums, which typically are 500 feet ceiling and 1-mile visibility. There aren’t any absolute rules when it comes to risk management, so you have to weigh all the variables and make decisions based on your best judgment, but it probably doesn’t hurt to delay the takeoff until the weather improves.

So, given your experience and proficiency, let me ask the question again: What are your IFR takeoff minimums?

Roger Sharp is the general manager for Flight Operations at Redbird Skyport in San Marcos, Texas, and runs its FAA Part 141 flight school. He is a designated pilot examiner for airplanes (land and sea) and helicopters, and he holds several ATP ratings.

On Christmas Eve, five people were killed when a pilot attempted taking off in foggy conditions. While the takeoff was legal under Part 91, had this been an airline flight, the plane probably never would have left the ground. Here's why.

The Accident Made National News

On Christmas Eve morning, a pilot attempted takeoff from the Bartow Municipal Airport, just east of Tampa in a twin-engine Cessna 340. He and his passengers were headed on a holiday day trip to the Florida Keys, and planned to return later in the day.

According to an airport employee working that morning, dense fog limited visibility at the field. The METAR observation at the approximate time of the accident confirms it:

METAR KBOW 241215Z AUTO 00000KT M1/4SM FG OVC003 12/ A3018 RMK AO2

As the airport employee recorded fog rolling over the airport, their cell phone captured noise from both the takeoff roll and crash. The fog was so dense that the airplane was never in sight of the camera.

So what went wrong here? Why did this pilot choose to takeoff in such poor conditions?

It will be awhile before the NTSB releases a preliminary report on the accident, but it's very likely that the fog played a significant role in the accident.

Under Part 91, pilot's typically don't have takeoff minimums. So, does that mean you can legally takeoff with zero visibility? Legally-speaking, some say yes and some say no. Let's dig a little deeper...

Standard Takeoff Minimums

Unless otherwise authorized by the FAA, for Part 121/135 operators and sometimes Part 91 operators, standard takeoff minimums under IFR are the following:

• 1 And 2 Engines: 1 Statute Mile Visibility
• 3 Or More Engines: 1/2 Statute Mile Visibility
• Helicopters: 1/2 Statute Mile Visibility

Unless carrier-specific, FAA approved Operating Specifications (Op Specs) allow for otherwise, Part 121 and Part 135 operators must comply with these standard takeoff minimums. Air Carrier Op Specs will likely state that the visibility must be a station-reported value or measured in terms of runway-visual-range (RVR).

But in most cases, these IFR takeoff minimums do not apply to pilots flying under Part 91, EXCEPT if the pilot is assigned and accepts a published departure procedure that includes takeoff minimums.

For example, if ATC issues you a Standard Instrument Departure (SID) procedure and you accept it, you must comply with the charted takeoff minimums. If the SID requires "standard" minimums, reference FAR 91.175. For anything else, you're obligated to follow what's published on the procedure.

This holds true for ODPs too. If you accept any instrument departure procedure, you must follow the required minimums for the procedure, even under Part 91.

Remember, if you can't meet the takeoff minimums or climb requirements, you have the option to decline the clearance and see what other options ATC has for you.

At large airports, you might be put on a "hold for release" for quite awhile, because you'll interfere with standard traffic flow. In reality, there are only a few instances when you'd choose to decline a departure procedure clearance.

Many airports have runway-specific, non-standard takeoff minimums published. They usually correspond with obstacle departure procedures. If you see a "T" within a black, upside down triangle on an FAA approach plate, the airport has non-standard takeoff minimums. You can also find a list of these airports at the beginning of the FAA's chart packet. If you use ForeFlight, look under the "Procedures - Departure" tab on the airport description page and click on "Takeoff Minimums."

Non-standard minimums are published when there are obstacle departure procedures to ensure you maintain safe clearance. For example, at the Mercer County Regional Airport (KHZE) in Hazen, ND, you have two options when departing Runway 32:

• 1) Depart from Runway 32 using standard minimums and a mandatory 215 foot per nautical mile climb to 2,700 feet.
• 2) Depart from Runway 32 when there are 900 foot ceilings and 3 statute miles of visibility for a climb in visual conditions.

While there's no obstacle note to explain the reason for this ODP, a quick look at a sectional map reveals that terrain rises more than 600 feet above airport elevation, beginning just two miles from the departure end of Runway 32. This is why the departure procedure has a climb gradient requirement or a minimum ceiling height to ensure you'll safely avoid terrain.

Do You Need A Takeoff Alternate?

IFR takeoff alternates are required when weather conditions are above takeoff minimums, but below landing minimums for the departure runway or airport. Takeoff alternates aren't required under Part 91, and usually only apply to Part 135 or Part 121 Air Carriers.

But while they aren't required for you under Part 91, creating your own takeoff alternate is always a good idea. If you decided to go, and if the ceiling and visibility on departure are lower than the instrument approach minimums, have an alternate airport nearby in mind.

If The Weather Is That Bad, Do You Really Need To Go?

Taking off in extremely low visibility increases your risk of a loss of directional control.

The pilot in this accident had little to no visibility during takeoff and immediately after rotation. While we don't know yet if fog was the only factor, or if there was a malfunction that triggered the event, poor visibility compounded the situation.

While takeoff minimums aren't prescribed for most flights under Part 91, it's always a good idea to set some personal standards. A good rule-of-thumb is to use the instrument approach minimums for the runway in use as your takeoff minimums. That way, you'll have plenty of lateral visibility down the runway, as well as ceilings high enough to return to the field if something goes wrong.

Become a better pilot.
Subscribe to get the latest videos, articles, and quizzes that make you a smarter, safer pilot.