RussR
En-Route
Just wondering about some of the reasons for various FARs, especially the Part 61 and 91 stuff, and wondering how many of them are based on statistical analysis or other study, and how many are just numbers pulled out of the air.
When we talk about aircraft certification, many of the requirements are based on physics, mechanical analysis of crashworthiness, etc. Sure, there's always some politics or negotiation going on, but at least there's usually at least a pretense of science involved.
But how about pilot certification and requirements? How much of it is based on some kind of analysis, and how much is completely arbitrary?
Examples:
- 3 takeoffs and landings every 90 days for currency. Why 3? Why 90 days? Why not 4 in 60 days or 5 in 6 months or some other number? Was there analysis of the accident rate and deterioration of skills, or did 3 just sound like a good number? Maybe it was the number that the Wright brothers included in the first training manual and it just kind of stuck?
- Hour requirements for ratings - Why 40 for a Private Pilot? 250 for Commercial? Why wasn't it set at 30 or 50, and 200 or 300?
- Why 6 instrument approaches for currency instead of 5? Or 10?
- Why is a cross country (airplane) 50 nm? Why not 25 (like helicopters) or 75 or 100 or some other number?
Those are just examples of the kind of thing I'm interested in. I'm not looking for specific answers to those questions, though. I'm more interested in learning about the analysis (if any) that went into the rules. Is there anywhere I can read about reasons for these types of rules (assuming there actually is a reason)? I'm sure some of the answers are in preambles to the NPRMs, but looking for other sources as well.
And I am fully aware that many of the rules probably have no analytical basis but are more a result of negotiations and politics.
Thanks!
When we talk about aircraft certification, many of the requirements are based on physics, mechanical analysis of crashworthiness, etc. Sure, there's always some politics or negotiation going on, but at least there's usually at least a pretense of science involved.
But how about pilot certification and requirements? How much of it is based on some kind of analysis, and how much is completely arbitrary?
Examples:
- 3 takeoffs and landings every 90 days for currency. Why 3? Why 90 days? Why not 4 in 60 days or 5 in 6 months or some other number? Was there analysis of the accident rate and deterioration of skills, or did 3 just sound like a good number? Maybe it was the number that the Wright brothers included in the first training manual and it just kind of stuck?
- Hour requirements for ratings - Why 40 for a Private Pilot? 250 for Commercial? Why wasn't it set at 30 or 50, and 200 or 300?
- Why 6 instrument approaches for currency instead of 5? Or 10?
- Why is a cross country (airplane) 50 nm? Why not 25 (like helicopters) or 75 or 100 or some other number?
Those are just examples of the kind of thing I'm interested in. I'm not looking for specific answers to those questions, though. I'm more interested in learning about the analysis (if any) that went into the rules. Is there anywhere I can read about reasons for these types of rules (assuming there actually is a reason)? I'm sure some of the answers are in preambles to the NPRMs, but looking for other sources as well.
And I am fully aware that many of the rules probably have no analytical basis but are more a result of negotiations and politics.
Thanks!
