Turbo-Arrow-Driver
Pre-takeoff checklist
Seems like this has the potential to generate a lively discussion. We'll see.
I'll start with this quote about holding pattern entries from Rod Machado's "Instrument Pilot's Survival Manual". My copy was printed June 15, 1998.
I've always kept this idea in mind as a backup when flying slow GA aircraft (e.g. 150 KIAS or less) in case I'm given a surprise hold with little warning.
In the old days, when hold entries were first designed, only bearings (and sometimes distances) to fixes were available to the pilot. With currently available equipment, graphic displays of predicted holding track based on aircraft performance and position are available. In thinking about these changes, a modification of the parallel entry has occurred to me. This could be applied to a portion of, or the entire area currently allotted to parallel entries. It would only make sense for aircraft equipped with GPS navigators with graphic displays.
An example is shown in the first Garmin simulator screen shot below. The AIM prescribed parallel entry is depicted by arrows, and the underlying holding pattern track by the dotted line. The distance between outbound and inbound legs is computed in real time by the GPS navigator -- presumably based on ground speed and a standard rate turn.
FAA requirements on protected holding airspace mean the protected airspace will extend more than 3nm on all sides of the holding fix. I believe the actual minimum is closer to 3.5nm, but in any case it is at least 3.0nm. This is based on the link below.
https://aviation.stackexchange.com/...protected-space-provided-by-a-holding-pattern
The aircraft is only 2.3 miles from the fix at this point, so why not turn directly onto the outbound leg here? The result is shown in the second screen shot below. It seems to me there's no danger of leaving protected holding space in doing this. It simplifies the holding entry significantly, thereby reducing pilot workload.
To make this a little more scientific, let's limit the maximum ground speed for this idea to 180 knots. I chose that because the standard rate turning radius is then 1.0nm, and it places the outbound leg 2nm from the inbound leg. By the same logic, the aircraft would need to begin the turn to outbound leg 1.0nm before reaching it, which would be 3.0nm prior to the holding fix. This is still well within the protected airspace.
Going by the Machado quote above, this is idea perfectly acceptable. At first blush, it seems reasonable to me for slow GA aircraft (e.g. ground speed below 180kts), but what other issues and concerns have I failed to consider? I'm also sure there will be a lot of different and likely strong opinions on this topic. I'm curious to see what others think.
I'll start with this quote about holding pattern entries from Rod Machado's "Instrument Pilot's Survival Manual". My copy was printed June 15, 1998.
"Perhaps the most important thing to understand about entries is that in the real world, it makes little difference how the pattern is entered. In real life IFR flying the most important thing to do is to keep the airplane within the protected holding pattern airspace during the entry. It makes absolutely no difference to the controller whether a pilot uses the AIM prescribe entry or an 'inverted whifferdill' entry with a full twisting dismount and difficulty factor of 4.9."
I've always kept this idea in mind as a backup when flying slow GA aircraft (e.g. 150 KIAS or less) in case I'm given a surprise hold with little warning.
In the old days, when hold entries were first designed, only bearings (and sometimes distances) to fixes were available to the pilot. With currently available equipment, graphic displays of predicted holding track based on aircraft performance and position are available. In thinking about these changes, a modification of the parallel entry has occurred to me. This could be applied to a portion of, or the entire area currently allotted to parallel entries. It would only make sense for aircraft equipped with GPS navigators with graphic displays.
An example is shown in the first Garmin simulator screen shot below. The AIM prescribed parallel entry is depicted by arrows, and the underlying holding pattern track by the dotted line. The distance between outbound and inbound legs is computed in real time by the GPS navigator -- presumably based on ground speed and a standard rate turn.
FAA requirements on protected holding airspace mean the protected airspace will extend more than 3nm on all sides of the holding fix. I believe the actual minimum is closer to 3.5nm, but in any case it is at least 3.0nm. This is based on the link below.
https://aviation.stackexchange.com/...protected-space-provided-by-a-holding-pattern
The aircraft is only 2.3 miles from the fix at this point, so why not turn directly onto the outbound leg here? The result is shown in the second screen shot below. It seems to me there's no danger of leaving protected holding space in doing this. It simplifies the holding entry significantly, thereby reducing pilot workload.
To make this a little more scientific, let's limit the maximum ground speed for this idea to 180 knots. I chose that because the standard rate turning radius is then 1.0nm, and it places the outbound leg 2nm from the inbound leg. By the same logic, the aircraft would need to begin the turn to outbound leg 1.0nm before reaching it, which would be 3.0nm prior to the holding fix. This is still well within the protected airspace.
Going by the Machado quote above, this is idea perfectly acceptable. At first blush, it seems reasonable to me for slow GA aircraft (e.g. ground speed below 180kts), but what other issues and concerns have I failed to consider? I'm also sure there will be a lot of different and likely strong opinions on this topic. I'm curious to see what others think.
