Common 121 Takeoff Minimums and Takeoff Alternate Questions

Airport Fogged InA common area of focus in airline interviews, Part 121 ground schools, and proficiency checks/type rides deals with the subject of regulatory takeoff minimums. Unlike in the part 91 world, airline pilots don’t enjoy the luxury of being able to choose their personal IFR takeoff limitations. Likewise, they often can’t opt to just wait until conditions improve – except in extreme cases. Instead, air carrier pilots must develop an intimate knowledge of the oft-confusing regulations that pertain to their flight operations.

No Simple Answer

Unfortunately, FAA regulations do not offer blanket, one-size-fits-all guidance that’ll serve you at every carrier operating throughout the US. Instead, the regs provide a significant degree of flexibility that allows each air carrier to tailor many of the details to its specific operations.

Why the apparent absence of standardization? Though all US airlines are regulated through 14 CFR Part 121, many variables (ex. airports used {and their infrastructure}, airplane models flown {and their performance characteristics}, and pilot {i.e. CAT II, CAT III} certification) make it unrealistic to expect all carriers to adhere to the same standards. Instead, many of the details that will guide you as a Part 121 pilot will come from your employer’s Operations Specifications (Ops Specs).

Ops Specs – C55

Ops SpecsSection C55 of your company’s Ops Specs will address all takeoff/alternate/approach details you’ll be expected to follow while flying for that carrier. Additionally, Part 121 (and, to an extent, Part 91) offer general guidance on many facets of such operations. If you’re not currently flying for a 121 carrier, make sure you’re familiar with the general regulations regarding airline operations; as your interview questions will be targeted towards the general regs. After beginning your new-hire class, your carrier’s Ops Specs details should be referenced for any such questions you’re asked during proficiency checks and type rides.

* Want to really impress your interviewers and stand out from the competition? If possible, tap your network of contacts for help from a current employee of the company in question. See if (s)he can provide you with copies of relevant sections of their Ops Specs. Spend sufficient time learning the specifics and applying them to various airports, weather conditions, etc. When a takeoff minimums or takeoff alternate question comes up in the interview, you can respond, “Under general regulations,                 and                 apply. However, per your company Ops Specs, we would use                       and                 in this instance.” Believe me, your interviewers will be impressed that you’ve gone the extra step to learn the details of their procedures.

Interview/Checkride-Type Questions

EbooksideSince pinning down the exact answers to airline-style takeoff/takeoff alternate questions is difficult given the variability of operating specs, I’ve opted to instead focus on considerations you should be careful not to overlook. If you’d like examples of interview questions of this nature, some worthwhile examples are available here, here, and here. Additionally, AirPloyment members have access to our database of airline questions and answers; which includes similar questions. Rather than attempting to just memorize the answers to these specific questions, I’d caution you to instead learn the concepts that determine such answers; as knowledge of the concepts can be applied to new circumstances.

Takeoff Minimums vs. Landing Minimums vs. Takeoff Alternate Minimums

One area that  is sometimes difficult for new Part 121 pilots to comprehend is the exclusivity of takeoff minimums from landing minimums. Try to picture each as completely separate from the other. Just because a particular airport is below landing minimums doesn’t (necessarily) mean you can’t depart. Instead, first attempt to consider the takeoff minimums by themselves. If the weather, airport equipment, aircraft capabilities, and FARs/Ops Specs will permit such a takeoff, nothing prevents you from departing. Only after you’ve examined the feasibility of a takeoff should you look at the landing minimums.

What if the airport is below landing mins? Then you’re required to have a takeoff alternate as outlined in 14 CFR 121.617. The exact weather mins for the takeoff alternate will be specified in the Ops Specs. In nearly all cases, your company Ops Specs will state the engine-inop, still-air distance in nautical miles (NMs); thus giving you an idea of the acceptable radius for an appropriate alternate.

Equipment Considerations

If you haven’t yet taken the ATP knowledge exam, the study guide booklet is one of the best prep tools you can use to develop your attention to detail. This is primarily because the questions tend to sneak in non-standard takeoff minimums, required climb gradients, inoperative equipment, and other factors that make it very easy to overlook a vital consideration. After you miss a few questions because of oversight, you’ll quickly learn to appreciate the need to pore over all available info.

In addition to the reported and forecast weather, you’ll need to make sure to pay careful attention to the NOTAMs information. A single inoperative item (ex. HIRL, centerline lights, RVR, etc) can easily turn a permissible takeoff into a no-go. Overlook a key factor and you could confidently tell an interviewer you’re good to go – when doing so would result in regulatory violations. Not a good way to make an impression. Avoid the urge to rush your answer. If possible, take a little extra time to ensure you don’t miss anything.

Standard, Published, and Ops Specs Requirements

Rock Paper ScissorsIn a rock-paper-scissors sort of way, you’ll need to consider a variety of possible takeoff minimums. Per 14 CFR 91.175 f(2), standard minimums are: 1sm (or 5000 RVR) visibility for a/c with 1-2 engines and  ½ sm (2400 RVR) for aircraft with more than two engines. This blanket regulation applies to all Part 121 operators unless additional factors waive or supersede this FAR.

Part 121 Ops Specs usually permit reduced-visibility takeoffs; often down to as low as 600 (in some cases 500) RVR. If standard minimums apply, your Ops Specs allow you to use your company’s reduced minimums; provided all requirements are met (read your NOTAMs!).

Ops Specs beat standard mins, but non-standard minimums trump them both. If non-standard (i.e. higher) mins are published, you must comply with the published minimums. No, your Ops Specs do not allow you to ignore these non-standard requirements. Make sure you scrutinize your Jeppesen or NACO (FAA) charts for indications of non-standards takeoff requirements. If such conditions apply, base your takeoff decisions on the specifics outlined in the non-standard procedures.

A/C Performance Capabilities

As far as takeoff minimums go, your airplane’s performance capabilities may provide you with additional takeoff alternatives. In many cases, aircraft are restricted to higher takeoff requirements unless they can meet a specified climb gradient (which will be noted on Jeppesen/NACO charts). If capable of the performance requirements listed, the aircraft are allowed to use lower takeoff minimums – ifthey maintain the required climb gradient to the specified altitude.

Be prepared for such questions on your interviews and checkrides. Convert the listed gradient to feet per minute (fpm). Consult your aircraft performance charts to see if your bird can meet them. Do NOT rush. Even if it takes longer, providing a correct answer is much better than offering a fast, albeit wrong answer.

A Word on Ceiling

One factor that often confuses pilots is the requirement for ceiling in determining alternate and approach minimums. Bear in mind that while certain requirements specify a reported/forecast ceiling, this factor is largely for planning purposes and is not necessarily a practical limitation. What do I mean? Consider this:

CeilingYour Ops Specs will likely specify that your destination airport must have at least                                    sm visibility and a ceiling of at least                feet or an alternate airport is required. Likewise, to be usable as an alternate, weather reports/forecasts must indicate the weather will be at or above                    sm visibility and              feet ceiling at the estimated time of arrival. These weather requirements are necessary for the destination/alternate airports to be listed for dispatch purposes. What about when you arrive?

When you arrive at the destination and begin an instrument approach procedure, visibility, not ceiling, is the controlling factor. Just look at 14 CFR 121.651 and 91.175. Neither regulation says anything about needing a certain ceiling to attempt (or land from) an approach – provided you have the required visibility and the “runway environment” in sight. You can still conduct the approach even if the reported ceiling is below published/authorized minimums.

Think about this: A ceiling (per 14 CFR 1.1) is the lowest broken (BKN), overcast (OVC), or obscuration layer. BKN ranges from 5/8 to 7/8 of sky coverage. In some cases, a full 3/8 of the sky at that altitude might not be obscured by clouds; meaning chances are very good that, with sufficient visibility, the flight crew will see the airport environment from the altitude where the ceiling exists. With this information in mind, don’t let an interviewer trick you into believing that ceiling determines whether you can depart or attempt an instrument approach.

Hitting the Books

As I’m sure you’re aware, aviation regulations and operating procedures require significant consideration of a variety of factors. They’re not something you’re bound to grasp without repeated exposure and a strong understanding of the components at hand. To best prepare for your flying career, try to review the appropriate materials on an ongoing basis rather than attempting to cram for an interview or checkride. A long-term approach will help ensure you truly understand the necessary material.
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