On September 2nd, 1998 Swissair Flight 111 crashed off Nova Scotia, with the loss of all 229 people on board. In this account, drawn from her memoir, Blunt Trauma, Ivy Bannister describes the aftermath of her sister Patty's death on that flight.

I found out the morning afterwards, when I switched on the radio. It was on the 7am news. A transatlantic airliner, Swissair Flight 111, en route from New York to Geneva, had plunged into the sea. I was in Dublin, where I live with my husband and two sons. Three thousand miles away in New York city, it was 2am, and my 80-year-old mother had also switched on her radio. She knew at once what I still only feared: that my only sibling Patty, an air hostess, had been working on that flight.

"I didn't cry and I didn't scream," my mother, Hortense, said to me two days later. "This was the 'big one'. This was the 'big enchilada'."

I knew for sure when I pressed playback on my flashing answering machine, having not even heard the phone, so taken over was I by malaise, and the need to keep my nine-year-old son Andrew's morning on an even keel.

My mother's voice, distant but calm, began to fill my head. "In case you haven't heard already," the voice said, "your sister was on Flight 111. We have lost her." Then the message was over.

"Oh Jesus, Jesus," I heard somebody cry, an appalling wail. For a moment I listened, wondering who was making that terrible noise. Then I realised that it was me.

The sound of our piano drifted through the house. Andrew was playing. The piece was from Titanic, a film that fascinated him. He had chosen the lament, the mournful music that unravels near the end, as a lifeboat rows through countless corpses, bobbing in the sea.

From the beginning, the raw knowledge of my sister's death by an aircraft crash was so consuming that everything around me seemed to relate to it. The media reinforced this impression. It was the media that provided my only concrete information about what had happened. On television I heard that the pilot had reported smoke in the cockpit. A witness described the scream of ailing engines. Another witness heard the sound of the impact, a shattering blast, although the aircraft had come down five miles offshore. Then a short clip flickered on the screen before my eyes: men in orange jackets unloading a body bag onto a wharf. Was it Patty, I wondered.

When I got to New York two days after the accident, it was the same. Headlines seared from the tabloids, and for weeks I pored over the New York Times's daily account of the ongoing recovery operations.

But everything appeared in a new light. Every step I took in that wonderful city reminded me of my sister. The streets themselves were changed, because we would never again walk them together. Glancing into a shop window, a pillow caught my eye. Its embroidered message read, "Anyone Who Says Money Doesn't Buy Happiness Doesn't Know Where to Shop". I felt like smashing the window and grabbing that pillow, but to what end? Patty was dead. Who else would understand how such a thing could bring us together for a fleeting moment of understanding? In this death-changed world, the most potent of all objects became my sister's flesh and blood.

"Have they recovered her body yet?" friends and acquaintances inquired, again and again. I had asked that question myself on the day after the crash. How I wanted that shell of her humanity to be recovered! The idea of it floating around - of it being untended and unrespected - was horrible.

Characteristically, my mother took the opposite stance. "I do not want her remains," she announced. "I told the airline to leave them at the bottom of the sea." The issue, however, was inescapable. The newspapers explained that in fact there were no bodies, only pieces: some tangled in the wreckage; others being trawled for with fishing nets. On the phone, a member of the Royal Canadian Mounted Police interviewed me about the particulars of Patty's physique. What colour were her eyes? Were they both the same colour? Were her ears pierced? Was any other part of her body pierced? Not until this crash, I was tempted to answer.

Two weeks after the disaster, the chief medical examiner of Nova Scotia, Dr John Butt, phoned me. A positive identification had been made. Alone in Patty's apartment, I took the call in her tiny kitchen, my bottom on the steps that doubled as her chair. I scribbled Dr Butt's words on to the notepad where she had written herself, a few hours before her death. A torso with part of a head. Portions of the upper legs still attached, more of one than the other. No arms.

"Were there any identifiable features?" I asked.

"No!" Dr Butt's response was hasty. Too hasty. Then, as if realising that he had betrayed some horror, he elaborated. "A dreadful impact," he said. "Tremendous dismemberment and fragmentation . . . an accumulation from the surface that continued to come up for several days."

I felt sorry for Dr Butt. I had done a quick sum. There had been 229 people on the aircraft, and an unborn child. At an average weight of 130lbs per person, that meant 30,000lbs of flesh - 15 tons of smashed-up people to recover, sort, catalogue, attempt to reconcile.

Later, in Mother's apartment, I told her how Dr Butt had said that only 10 of the dead had been identified, and that no further identifications were expected for a while.

"So we're one of the lucky ones," she said with withering irony.

For the moment, Dr Butt's description was a help. It convinced me that Patty's death was instant, that she would have felt little physical pain. But it did nothing to lessen the sense of her mental suffering. The crisis in the aircraft - from the first whiff of smoke to the denouement - lasted 20 minutes. At what point did my sister realise that she was going to die? Patty was bright, she knew aircraft, and she was pessimistic. It seemed to me that she had known from the beginning.

"I don't believe this," I heard her saying. "I don't believe this is happening."

For me, her fear took shape like a great monolith that consumed everything, that stopped the heart and froze the breath.

I had to empty out Patty's apartment, and there, the power of objects was overwhelming. Being there without her was itself an intrusion. Freshly ironed shirts hung sentinel over her bed. The air sighed, as if disturbed by my invasion. Her nightie was on the back of her bathroom door. I gripped it, smelled the scent of her body.

The apartment was bursting with things. Patty had travelled, and she had collected, and the disappointments in her life reverberated through the quantities of objects that she left behind.

"You have a husband," she had yelled at me once. "You have children. All I have is my possessions. My possessions are everything to me. Everything."

Most poignant was the tennis racket cover with the word LOVE on it. Once I had watched her embroider that cover, her long fingers pulling the threads through. Now I saw only the word, and felt her yearning for relationships everywhere in that over-stuffed place. There was the massive trousseau, collected for a wedding day that never came: the Rosenthal china service for 12; the three dozen Waterford crystal glasses; the shelves full of pristine sheets, towels and nightgowns.

But romantic love had eluded my sister, and as I worked through the mountains of belongings - pulling things out, jamming them into sacks and boxes - I could not escape the fact that there had also been a profound failure of love in our own relationship. We had not, could not have, never had been close; and our meetings were characterised by anger on her part, and my own tendency to endure anger in silence, while yearning for escape.

And yet I had longed for her friendship, for easy-going companionship, for understanding and respect - and most of all, for the knowledge that we could count on one another. For years I had approached each meeting in the hope that we could start again, that our relationship could blossom.

Now as I ripped through the collections of herlifetime, and waded through accumulating dustballs, that hope was gone. In a ghastly way, by dismantling her apartment, I was finishing off the job that Swissair Flight 111 had begun.

My mother came to Patty's apartment only once. From the jam-packed wardrobes she plucked a ruffled blouse. With care, she matched it to a frilly skirt. She held the outfit up, a fluttering confection of baby blue. "Tell me," she said, "how could a woman who wore clothes like these die in an airplane crash?" I was glad that Mother kept away. But I feared for her.

"Your sister and I were like an old married couple," she said. And they were. What better way to describe their intimate, turbulent closeness, their habitual bickerings? They had been the significant others in each other's life, and now my mother had no one else. She did not believe in friends. On the subject of her own funeral, she had always said, "No funeral, because people I don't like would come."

Without Patty, and with me returning to my family in Ireland, how would Mother get on? At 80 years of age, she was still a formidable figure. Even while my father was alive, Mother had always been boss. In a pack of hounds, she would have been top dog. "Your skirt's too short," she would shout at women in the streets, and she enjoyed provoking flaming rows with strangers.

She took orders from no one, and when I suggested that she give a set of spare keys to a cousin, she dismissed me in a colourful fury, peppered with expletives that Richard Nixon would have admired.

So I returned to Dublin and tried to reconnect with life. But even in the theatre, when a smoke machine was turned on, the stage vanished before my eyes to be replaced by a fog-blanketed sea, and rolling waves thick with aircraft fuel and wreckage.

I worried about Mother. I phoned New York every night. Sometimes, I didn't get her. When I voiced my concern, she exploded: "Shut up! I can look after myself!"

Then the inevitable happened. She broke her hip. As I found out later, she fell over the clutter in her apartment. Predictably, she refused to acknowledge that she had a problem. Unable to stand, she crawled on her backside, propelling herself with her arms. She made it to the phone and called her lawyer, with information that he had asked for. Having hung up, she backed her way into the bathroom, where she discovered that she could move no further.

In the meantime, I phoned from Ireland. That first night, I thought nothing of not getting through. The second night was Christmas Eve. I rang with progressive uneasiness. Perhaps someone who had known my sister had taken her out? Unlikely, but still . . . On Christmas morning, I contacted the cousin, who broke down the door. Ringing from her apartment he said, "Your Mom's okay, but she needs some help."

I could hear her in the background. "No ambulance," she was insisting. "I won't go in any ambulance."

What followed wasn't easy. I returned to New York, once again abandoning my family in Dublin. All my life, I had followed my mother's instructions, or else avoided her. Now I could do neither. Bereaved and helpless, my mother fought against abandoning her autonomy, privacy and dominance. For three months, her apartment trapped us both, while, battered by her rages, I nursed her through her crisis. It might have been a Martin McDonagh play, only we were living it.

I wrote Blunt Trauma because I couldn't write anything else. It released what was bottled up in my mind. The first draft was a whopping, unreadable 200,000 words. I pursued publication because I wanted my sons, Richard and Andrew, to understand some of the pitfalls of family relationships. Most of all, I wanted them to strive to be each other's best friend. By seeing it in print, they will know that I really mean it.

Blunt Trauma will be published by Ashfield Press on Sept 6, €13.99