4 ms·

I don't have data on flight miles or flight segments by type of aircraft, so let's do a quick and dirty estimate. Let's say there are 40,000 commercial aircraf

I don't have data on flight miles or flight segments by type of aircraft, so let's do a quick and dirty estimate. Let's say there are 40,000 commercial aircraft worldwide and 350 of these are the Boeing 737 Max [0]. If all aircraft are equally likely to crash, then the probability of a given crash being a 737 Max is 350/40000 = 0.00875. The probability that two crashes are both 737 Max is 0.00875 * 0.00875 = 0.0000766 It's extremely unlikely that an aircraft representing less than 1% of the global fleet would crash twice in a short period of time unless there is a serious defect with that aircraft. That's well past probable cause at this point. This aircraft should be grounded until they figure this out. [0] https://en.wikipedia.org/wiki/List_of_Boeing_737_MAX_orders_and_deliveries https://en.wikipedia.org/wiki/List_of_Boeing_737_MAX_orders_...

markdown 8y ago
Active fleet today: https://twitter.com/flightradar24/status/1104838043792490497 https://twitter.com/flightradar24/status/1104838043792490497
Steko 8y ago
> The probability that two crashes are both 737 Max is 0.00875 * 0.00875 = 0.0000766 You need to multiply this by every combination of two crashes in the observed time period with starting and endpoints not cherry picked to include 737 max crashes though.
- panarky 8y ago
  Be my guest. You'll find that the probability of a rare aircraft crashing twice in a short period of time is infinitesimal, unless that aircraft contributed to the catastrophe.
  - Steko 8y ago
    It's hardly infinitesmal, that's my point. With an average of 175 737's operating since launch, 4K total widebody commercial aircraft and over a dozen widebody crashes in that period, you get over 10%. Some estimates there but you still have the endpoint issue as well.
    - panarky 8y ago
      There have been a total of 5 commercial air disasters in 2018 and 2019 with fatalities that didn't involve hijacking, landing short of the runway or overshooting the runway [0]. And that includes the crash of a cargo flight with no passengers where the crew was killed. The 737 Max 8 was involved in 2 of those 5 disasters. There are between 25,000 and 39,000 commercial aircraft in service depending on who you ask [1]. With 350 737 Maxes delivered so far, that's at most 1.4% of the total today, probably less than half that this time last year. Let's call it 1% on average for 2018 and 2019 combined. There are 10 ways you can have 2 Max crashes out of 5 total crashes. So the probability is 10 * 0.01^2 * 0.99^2 = 0.00098 Even accounting for n choose k and longer endpoints, it's still an infinitesimal probability that we'd see two catastrophes with the same rare aircraft -- unless that aircraft contributed to the catastrophe. It should be grounded. [0] https://en.wikipedia.org/wiki/List_of_accidents_and_incidents_involving_commercial_aircraft#2018 https://en.wikipedia.org/wiki/List_of_accidents_and_incident... [1] https://www.telegraph.co.uk/travel/travel-truths/how-many-planes-are-there-in-the-world/ https://www.telegraph.co.uk/travel/travel-truths/how-many-pl...

markdown 8y ago

Active fleet today: https://twitter.com/flightradar24/status/1104838043792490497 https://twitter.com/flightradar24/status/1104838043792490497

Steko 8y ago

> The probability that two crashes are both 737 Max is 0.00875 * 0.00875 = 0.0000766 You need to multiply this by every combination of two crashes in the observed time period with starting and endpoints not cherry picked to include 737 max crashes though.

panarky 8y ago
Be my guest. You'll find that the probability of a rare aircraft crashing twice in a short period of time is infinitesimal, unless that aircraft contributed to the catastrophe.
- Steko 8y ago
  It's hardly infinitesmal, that's my point. With an average of 175 737's operating since launch, 4K total widebody commercial aircraft and over a dozen widebody crashes in that period, you get over 10%. Some estimates there but you still have the endpoint issue as well.
  - panarky 8y ago
    There have been a total of 5 commercial air disasters in 2018 and 2019 with fatalities that didn't involve hijacking, landing short of the runway or overshooting the runway [0]. And that includes the crash of a cargo flight with no passengers where the crew was killed. The 737 Max 8 was involved in 2 of those 5 disasters. There are between 25,000 and 39,000 commercial aircraft in service depending on who you ask [1]. With 350 737 Maxes delivered so far, that's at most 1.4% of the total today, probably less than half that this time last year. Let's call it 1% on average for 2018 and 2019 combined. There are 10 ways you can have 2 Max crashes out of 5 total crashes. So the probability is 10 * 0.01^2 * 0.99^2 = 0.00098 Even accounting for n choose k and longer endpoints, it's still an infinitesimal probability that we'd see two catastrophes with the same rare aircraft -- unless that aircraft contributed to the catastrophe. It should be grounded. [0] https://en.wikipedia.org/wiki/List_of_accidents_and_incidents_involving_commercial_aircraft#2018 https://en.wikipedia.org/wiki/List_of_accidents_and_incident... [1] https://www.telegraph.co.uk/travel/travel-truths/how-many-planes-are-there-in-the-world/ https://www.telegraph.co.uk/travel/travel-truths/how-many-pl...