I was fascinated Greg Bagwell’s thread on X/Twitter last week and I can’t help but want to share it with you.
Greg Bagwell CB CBE is a retired Royal Air Force Senior Commander who served 36 years, ending his career as Deputy Commander (Operations) in RAF Air Command, the service’s most senior operational role. He commanded major operations and has more than 4,000 flight hours, primarily in Tornado aircraft.
Your thread discusses something that sounds deceptively simple but quickly becomes complex: the mathematics of maintaining 24-hour air patrol coverage.
Here’s a quick tutorial on how to schedule a combat air patrol and evaluate the number of aircraft needed to complete it over a 24-hour period. In theory it works for any aircraft, but let’s use the example of a Poseidon P8 Maritime Patrol aircraft.
Their example is the Boeing P8 Poseidon, a modern reconnaissance and maritime patrol aircraft developed for the US Navy and allied forces, currently in operation in the United States, United Kingdom, Australia, New Zealand, Norway, South Korea, Germany and Canada. The fuselage is a reinforced Boeing 737-800 with a weapons bay, a sonobuoy deployment system for anti-submarine warfare and dedicated military avionics. The P8 typically operates with a crew of nine: two flight crew and seven mission specialists. It has a maximum speed of 490 knots (564 mph or 955 km/h) with a ceiling of 41,000 feet (12,500 m). It has a combat radius of 1,200 nautical miles (1,383 miles or 2,225 km) with four continuous hours performing its mission in the designated target area before having to return the distance of up to 1,200 nautical miles to return home.
A P8 has the capability of conducting a 4-hour patrol at a distance of 1,200 nautical miles. The time it takes to focus on the task and return is a [circa] 4 hours round trip – with me so far? Once a plane is patrolling, it will be necessary to take off a second plane when the first has 2 hours of autonomy left.
Confession: I’m a little confused by your use of endurance here, but what is clear from your example is that the P8 has a fuel endurance of eight hours (it can fly safely for eight hours).
The patrol mission lasts two hours of flight, four hours over the target area and then two hours back.
When the first P8 is two hours old patrol left, the second P8 must depart for its flight towards the target area, that way it arrives at the target area just as the first P8 leaves. Otherwise they don’t have continuous coverage, right?
The following tweet confirms that this is what Bagwell meant: the second plane has to take off when the first has two hours left on patrol.
So if the first plane took off at 22:00 to patrol at 00:00, the second plane would have to take off at 02:00 to patrol from 04:00 to 08:00. Since the next plane must take off at 06:00, it cannot be the first plane, which will only land at that time.
This makes sense. The first plane stops patrolling to return to base at 04:00 and the second plane takes over. It will arrive at 06:00, which is the same time the next plane is due to leave, so we need three planes.
A third plane then takes off at 06:00 to patrol between 08:00 and 12:00. Now, the next plane must take off at 10:00. Since this is 4 hours after the first plane landed, it can be used for the fourth patrol post.
So far, so good.
If aircraft remain in service and sufficient crews are available, this cycle can continue. So in theory 3 aircraft are needed to maintain a 24 hour patrol using these assumptions. Resistance could be increased by air refueling and reduced by using more fuel.
Well, I’ve almost mastered it, but I’m not sure I’m ready to tackle air refueling! Fortunately, the math lesson seems to be over.
In a peacetime training environment, you can compress this timeline to get valuable training for more crews or preserve fatigue (crews and aircraft!). Therefore, observing such activity to make force planning assumptions is a false premise.
I was wondering about crew fatigue: it’s an eight-hour flight day. The first P8 returns home as the third departs… but it has to turn around and fly to relieve the third patrol in just four hours, so that will surely require a new crew.
In fact, the first comment in the thread asks exactly about this.
So many questions. How does serviceability decrease over time? How much rest do crews need between sorties and does this increase over time? So for how many days can an advanced fleet of 6 to 7 aircraft effectively maintain this speed? How does AAR affect rest and serviceability?
Greg Bagwell:
A crew doing an 8 hour mission would expect at least 8 hours of rest (I remember a 10 hour rest with at least 8 available for sleep), but in peacetime you would only want to do one of those per day. There would be a limit of hours per month, so refueling just eats up those hours faster.
These are more for peacetime, you would be at much greater risk in wartime.
Some tradeoffs may be made depending on risk appetite/need. The airframe and engines must be quite robust, so care will have to be taken with specialized equipment.
And later in the thread, Bagwell confirms that at least six crews along with an additional aircraft are needed to deal with maintenance issues.
Is it advisable or even feasible to have a fourth plane available in case one of the first three suffers some type of accident that requires repair and takes longer than expected?
Greg Bagwell:
Absolutely.
So what is the amount of equipment needed to do this?
Greg Bagwell:
Sustained? Probably 6. So it’s not a question of fuselage numbers.
The point is that the P8s, in your example, are not the limiting factor, but rather the number of crews trained to operate them.
Thanks to Greg Bagwell for laying it out so clearly. The man is a national treasure!
