Several times, my flight has been delayed when passengers don't make it to the gate in time and then (after a long wait) the baggage-handlers have to go into the holds and manually find the bags to offload.

First, is this a legal requirement? Do all carriers follow this same practice?

If so, then why is this a security risk any greater than the same flight anyways carrying air-cargo in its hold? Flights do that, correct? Not all cargo space is filled with checked-in baggage?

Does anyone know the rationale behind this calculation? If the hold anyways contains unaccompanied cargo then why treat unaccompanied passenger baggage as a high risk?

Also, historically, is there a record of such offloaded bags (for missing passengers) actually turning out to be containing explosives?

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    $\begingroup$ When the situation is more nervous than usual, a variant of having the baggage handlers go into the holds and manually finding the bags to offload, is to unload all baggage onto the ramp and then have the passengers deplane and identify their baggage individually. Really time consuming. The one time it was done on a flight I was operating, it delayed us by around two hours as I remember. $\endgroup$
    – Terry
    Commented Oct 7, 2018 at 21:49
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    $\begingroup$ In the 1990s at the carrier I flew for, air cargo on pax flights from JFK to Tel Aviv was accepted only from known and trusted sources, and when the security alert level was high, cargo was sometimes put in altitude chambers to check for barometric devices. $\endgroup$
    – Terry
    Commented Oct 7, 2018 at 22:01
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    $\begingroup$ @Terry Interesting! Can you tell more? "More nervous than usual"? What are they trying to catch by doing this? A malicious loader? $\endgroup$ Commented Oct 9, 2018 at 3:26
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    $\begingroup$ The carrier's primary scheduled flying was JFK-TLV, and in some months we carried more pax on that route than El Al, the Israeli state airline. It was a Jewish-owned airline and, like El Al, as I understood it, we were considered to be at risk for terrorist activity. For example, at Amsterdam Schiphol, we were at times escorted to and from the runway by armored vehicles, one in front, one in back, and one at each wing tip just as El Al was. $\endgroup$
    – Terry
    Commented Oct 9, 2018 at 18:03
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    $\begingroup$ At the time, I was flying for Tower Air, a small (23 747s) JFK based carrier. I joined them in 1995, retired in 1999, and they went bankrupt in 2000 or so. Some of my experiences with them are detailed at terryliittschwager.com/emailjournal.php and terryliittschwager.com/talking-of-flying.php, although I have yet to finish that last link. Who knows whether I'll ever get that done. $\endgroup$
    – Terry
    Commented Dec 4, 2018 at 7:43

2 Answers 2


Partial answer:

The rule about offloading passenger bags is known as Positive Passenger/Bag Matching. It was introduced after the Pan Am 103 bombing in 1988 where a bomb was placed in a suitcase that was checked through to New York without belonging to any passenger on the plane.

By the practices of the time, all bags tagged with the right flight number would be loaded onto the plane, without pausing to cross-reference them to passenger manifests. The investigation never found out for certain how the suitcase with the bomb had entered the baggage system (an inside job at Luqa airport was suspected but not proved), but the outcome was to require matching of all the bags to actual boarded passengers before departure.

So this is not necessarily a case where explosives were placed in the checked bag of a passenger who should have boarded but didn't -- but it is close enough to see that the risk is not pure fantasy.

The rule applies to all international passenger flights, but not to US domestic flights; the US authorities apparently have better trust in their ability to screen checked bags for explosives before loading them onto a plane.

I would assume that air cargo also undergoes similar screening and that is why it is not subject to PPBM rules -- even outside the US there is better time to screen cargo thoroughly than there is for bags that are only checked an hour or two before departure.

This Travel.SE question and its answers have more information about PPBM.

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    $\begingroup$ Thank you! Do you mean that in US domestic flights they don't necessarily offload bags for missing Passengers? $\endgroup$ Commented Oct 9, 2018 at 3:28
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    $\begingroup$ @curious_cat: That's what I understand, but I have it only second-hand through the Travel question I linked. $\endgroup$ Commented Oct 9, 2018 at 3:30
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    $\begingroup$ That's true. I've certainly missed a US domestic connection only to find that my bag arrived before me. The US did practice PPBM for a few years, but I don't know when they stopped. $\endgroup$
    – mkennedy
    Commented Oct 13, 2018 at 21:47
  • $\begingroup$ Info rejected as an edit, but worth keeping: Positive passenger bag match was already being conducted by certain air carriers before the bombing of Pan Am 103. When Air India Flight 182 was bombed in 1985, the International Civil Aviation Organization (ICAO) mandated PPBM for all flights. Therefore, PPBM was already mandated when Pan Am 103 exploded. The investigation determined the process was not conducted by Pan Am. (Jeffrey C. Price, lead author, Practical Aviation Security: Predicting and Preventing Future Threats). $\endgroup$
    – Ralph J
    Commented Aug 3, 2023 at 3:02

There are a number of questions in here, but there is one common misconception.

Unaccompanied baggage: Positive passenger bag matching (PPBM, offloading of unaccompanied baggage) is not required by US, EU, or ICAO standard.

ICAO Annex 17

4.5.3 Each Contracting State shall ensure that commercial air transport operators do not transport the baggage of persons who are not on board the aircraft unless that baggage is identified as unaccompanied and subjected to appropriate screening.

If the unaccompanied baggage is screened via approved advanced detection systems, or hand-searched, it may fly without the passenger. Of course, an airline can merely offload the baggage if they do not have the proper screening.

The appropriate screening standards are set out in EU EC 2320/2002 5.2.2 and 49 USC 44901.

The US set the eventual requirement for all baggage to be screened with advanced systems by default. Additionally, the EU allows normally-screened baggage to fly without the passenger if the passenger is separated from the bag due to reasons outside their control.

Air cargo: Post 9/11, the US implemented the "known shipper" program which requires all cargo to be from TSA pre-approved shippers with approved security programs. Airlines cannot accept cargo from the public.

One change that resulted from this are that passenger aircraft cannot carry parcel mail (only lightweight letter mail). Additionally, cargo carried on passenger aircraft is now screened the same as passenger baggage.

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    $\begingroup$ Thanks! What's some scenarios where "passenger misses the flight due to reasons outside their control" but bag makes it? $\endgroup$ Commented Dec 1, 2018 at 9:16
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    $\begingroup$ @curious_cat It would be the opposite most likely, a passenger makes the flight but the bag doesn't. They can then send the bag by the next flight. Perhaps one scenario is the passenger is held up by immigrations or security but their bag isn't. I changed the wording slightly. $\endgroup$
    – user71659
    Commented Dec 11, 2018 at 18:59
  • $\begingroup$ @curious_cat a few years ago I was stuck at AMS due to snow and my original connection was cancelled - at 11.15pm, KLM put us on the 11.30pm flight, and we ran to the gate to get it but they had closed the gate. As a backup, we were also put on the 6am flight the next morning so we got that instead. Our bag was waiting on the conveyor at our destination about 2 minutes after we got off the plane (small regional airport), so it had made the earlier flight with no problems... Everyone else on the plane had to wait for their bags to come. $\endgroup$
    – Moo
    Commented Jan 9, 2020 at 21:46
  • $\begingroup$ Baggage may be transported unaccompanied IF it has been appropriately screened, but checked baggage should not be carried if the checking passenger is not on the same flight (by their own actions!). These rules were brought in in the days before suicide bombers because terrorists (and extortionists) would check a bag with a bomb and then choose not to get on the flight. $\endgroup$
    – Paul Smith
    Commented Jan 10, 2020 at 22:55

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