Confirmation that the Russian Airbus A321 that crashed in Egypt was felled by a homemade bomb puts the loss in the hull war insurance market, a segment of the aviation market already reeling from several major losses.

But the October loss is unlikely to turn the soft market for aviation hull war, or greatly affect conditions in the wider aviation hull and liability insurance market, which still has ample capacity, sources say.

A year from now, the situation could be quite different, however.

The vast majority of commercial airline fleets renew their coverage in the final quarter of the year, and plentiful capacity and low overall aviation losses mean that average rates likely will fall about 15%, experts say.

But those airlines that have a record of attritional — or low-level — losses may find greater underwriter scrutiny at this renewal, experts say.

In addition to the Metrojet flight that Russian authorities last week said was indeed brought down Oct. 31 in the Sinai Desert by a homemade bomb, the aviation hull war market suffered losses from the Malaysia Airlines flight MH17 that crashed in July 2014 in the Ukraine as well as the March 2015 crash of a Germanwings GmbH jet in the French Alps that a co-pilot deliberately crashed. Nearly 700 people died in the three crashes, which killed all aboard.

Moscow-based Ingosstrak Insurance Co. insured the Russian jet and Allianz Global Corporate & Specialty S.E., a unit of Allianz S.E., led its reinsurance program. Lloyd's of London led the Malaysia Airlines and Germanwings hull war coverage.

The insured hull loss for the Russian plane is likely to be about £24 million ($36.6 million), sources said.

While the hull war market is “feeling the impact” of the recent losses, average rates still will fall during the current renewal period, said Nigel Weyman, CEO of aerospace at JLT Specialty Ltd., a unit of Jardine Lloyd Thompson Group P.L.C. in London.

There may be some hardening in that segment of the market in 2016, he said.

Until the recent losses, the hull war market had about nine years of relatively low losses, said Simon Harker, chairman and CEO of the global aviation and aerospace division practice at Marsh L.L.C. in London.

According to one market source, aviation hull war underwriters attempted to increase rates after the Malaysia Airlines loss, but that lasted only about a month.

There is still ample capacity for aviation hull war business, said Steven Schmidt, senior underwriter of aviation facultative at Munich Reinsurance Co. in Germany.

And although the hull loss will fall on the war market, liability losses likely will be much larger and will fall to the liability market. While significant, the losses likely will “not be market-changing,” Mr. Weyman said.

While average renewal rates are expected to fall about 15%, declines will vary from insurer to insurer, he said. Many well-established “flag carriers” already pay extremely low rates and likely will see smaller decreases than newer fleets that are expanding with new aircraft and may see larger “recalibrations” of their rates, he said.

While rates continue to decline, underwriters' margins are becoming extremely squeezed, and it may not be sustainable for some insurers to continue underwriting the business, said John Rooley, head of aerospace at Willis Group Holdings P.L.C. in London.

While overcapacity has been a factor in rate reductions, some underwriters are “beginning to rethink their participation,” Mr. Weyman said.

Though there has not been any significant withdrawal of capacity, aviation underwriters are taking a closer look at buyers with high attritional losses.

Where insurers are trying to “underwrite through the cycle,” buyers with high attritional losses will come under “greater scrutiny,” Mr. Harker said.

And where clients “have a track record of attritional losses such as hard landings or hangar rash,” which are minor accidents, coverage is becoming harder to place, said Mr. Rooley.

But he noted that in some cases where airlines' loss record is pretty good, underwriters will take the business even at levels that are not hugely profitable to secure a position on a program once the aviation market does turn.