It’s an interesting question.
Look, any major airline that operates that aircraft type does so in compliance with the Flight crew operating manual, and in concert with the manufacturer.
But Airlines do have their own unique standard operating procedures for a variety of things that are not covered by the manufacturer, and allow them to be in compliance with regulatory environment, set up by the country in which they operate.
Further, the manufacturer typically sends out updates over the service life of a airplane, for example, on the 757, a rejected takeoff, used to consist of throttle to idle, auto throttles disconnect, reversers extend, verify speed brake extension, but after a couple of runway over-runs on a rejected takeoff, the third step is now, extend speed brakes manually, and the fourth step is extend the reversers. Selecting reversers will extend the speed brakes, and that used to be the logic, but now, 30+ after the airplane was put into service, Boeing says, “do it this way” - so, that’s how we do it.
The world is extremely complex when it comes to the interesection of manufacturer recommendations, various country regulatory bodies, including ICAO, and airline operating
Some airlines will slightly modify how they operate an airplane in the interest of “harmonization” of operating procedures across fleet types. For example, let’s say that aircraft X allows you to put the auto pilot on at a very low altitude, but aircraft Y does not. Well, the airline may choose to simply use the more restrictive altitude across their multitude of fleet types to simplify pilot training, for example. They are still fully compliant with the aircraft flight crew manual for both aircraft, because they use the more restrictive engagement altitude, and they have accomplished their objective of simplifying pilot training.
Even airlines that only operate a single aircraft type have their own SOP‘s that vary a bit from the manufacturer.
Some things are negotiable. Some things are not, like the rejected takeoff change above.
Decades ago when I was an instructor on the 747–400, I did a lot of “Contract“ Training. Airlines (and the USAF, by the way, we had over 50 customers around the globe) would lease our simulators in our instructors and conduct their Crew training with us in Denver. When you look at the cost of buying, housing, and maintaining a simulator, and training the instructors, it does make sense for Airlines with smaller fleets to simply lease the time, and I got to train Crews from Atlas, as well as Air New Zealand.
Atlas and Air New Zealand chose to operate the airplane slightly differently than we did. So, part of my “check out” as a Contract training instructor, was to demonstrate proficiency with their operating procedures, and their techniques. For example, they trained to a circling Approach with 800 foot ceilings in 2 miles visibility. For a category D airplane, like the 747, that is not a simple proposition. It is allowed by the regulatory bodies, and it is allowed by Boeing, but there is some risk there, so we do not allow circling below 1000 foot ceiling in 3 miles visibility, which is VFR, so our training does not include circling Approach and our type ratings note that restriction. Airlines that may need circling Approach to get into remote, smaller, or Third World airports, may need that additional training, and be willing to maintain proficiency, but a major airline that flies only to major airports with their 747s may not see a return on the investment in the training, or in trying to maintain proficiency, in that one area.
Unfortunately, there are many pilots who do not have experience across Airlines, or do not have experience across multiple aircraft types, who will look at how their airline operates a single aircraft type and then say “anything other than our SOP is dangerous and unsafe, and I would demand that that pilot be reprimanded/fail a check ride if they operated the airplane in that way.”
This perspective is naïve. And it fails to understand that the key to safety is NOT rigid adherence to one perspective.
The key to safety is the crew’s adherence to the same set of SOPs. A crew that has a clear understanding of the SOP that they used to operate that aircraft type, that works in concert, in Harmony, is far better than a crew that has a “better” SOP but that doesn’t execute it well.
Mishaps, and accidents, and incidents, generally result from the deviation from SOP, or a crew’s failure to adhere to their SOP. It’s not the SOP that matters as much as the crew’s compliance, and the effectiveness of the crew in executing that SOP.
General George Patton once said, “A good plan, executed violently now, is better than a perfect plan next week.”
And the general is absolutely right. It is inexperienced, or perhaps myopic, pilots that argue over that minutiae, who are convinced that they are right, and everyone else is wrong, who are trying to create the perfect plan, when the key to success is having a good plan and executing it with excellence. We need to be focused on the excellence of execution, not the perfection of the plan.
Even worse, is the pilot who is convinced that they are absolutely right, and that their company SOP is wrong, so they deviate from the SOP because “they know better“. We have a name for those pilots, publicly it is those who are intentionally noncompliant, and intentional noncompliance greatly drives up the error rate of crews in normal operations, and severely degrades their performance in the non-normal operations that I see when training and checking in the simulator. The inner circle name for such pilots can’t be repeated on BITOG…
So, I wouldn’t worry too much about nuances on how airplanes are operated. All are operated in compliance with manufacturer and regulatory guidelines and requirements.
The truly professional pilot understands that it is the adherence to a common set of SOP, and the crew’s ability to execute that SOP, that matters much more than the precise nature of the SOP itself.
Let the self-righteous, and training center wonks, argue over this method or that, or which tiny detail should be modified and why. Let them pound the table while trying to separate pepper from fly poop, while the rest of us pay attention to the larger picture of human performance in the complex technical and regulatory environment that is modern aviation.
